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Why did the face of human species changed so much during the course of its evolution?
I recently watched this video which showed the evolution of facial features of the modern man
https://youtu.be/-69K7E0UlBI
I'm wondering what evolutionary advantage did we get by having our face from this-

(reconstruction of the face of Australopithecus)
To this-

(Homo sapien sapien)
"In other words for what advantage did nature selected our present face?"

There are many things going into the evolution of our face. It is not as simple as discussing a single trait. Your question is therefore quite broad. So I will just pick up three different traits and talk a little bit about them. Those traits are

hairs
size of the jaw
cranial capacity

As I will only say a few words, you will have to look for more advanced information by yourself if you want to deepen your knowledge.
But first, let me make a few other comments
A few comments
Panselectionist view of evolution
When you say what advantage did nature selected our present face?, you seem to assume that any evolutionary had to be brought about via a selective pressures. Yet, there is so much more to evolution than just natural selection. Not every trait has been selected for (otherwise we would not have any genetic disease). There is for example genetic drift who is also a very important evolutionary force.
On this subject, you might want to have a look at the paragraph Did you say Natural Selection? of this answer to Why don't mammals have more than 4 limbs? and to Why do some bad traits evolve, and good ones don't?
Accuracy of your Australopithecus's face
In the reconstruction of the appearance of a extinct lineage, there is always some part of artistic representation to fill the gap of what we don't know. One should investigate the exact method used to recreate this image before assuming that Australopithecus looked exactly like that.
For more information have a look at In reconstructions, how are various shapes of facial features determined from skull only?
On top of that, please note that there is variation in faces within a species. This is true for Homo sapiens today and it was true for other great ape lineage. More importantly, there were at least 6 species of Australopithecus (see wiki > Australopithecus).
Human species or hominini lineage?
Your question is

Why did the face of human species changed so much during the course of its evolution?

When we say "human species", we typically refer to H. sapiens (or even H. sapiens sapiens). Based on your images, you seem to rather ask about the evolution of faces in the hominini lineage and not only in H. sapiens as Australopithecus is not the same species as us. Australopithecus is actually a genus (other than Homo) containing several species.
Evolution of a few facial traits
Hairs
We've lost plenty of hairs! Have a look at the post Why did humans lose their fur? to understand why.
Size of the jaw
Here is a timeline of evolution of hominini

As you can see, Australopithecus did not know how to cook. They did not know how to control fire. The first to have a good control of fire were probably Homo erectus.
By cooking, we pre-digest our food, leaving much less work for our digestive system, including the physical mastication performed by our jaws and teeth. As a consequence our jaws reduced in size (Wrangham and Conklin-Brittain 2003, Lucas et al. 2006; See also this book from Lucas).
Size of the brain
H. sapiens cranium is about 3 times the size of Australipithecus cranium (Leigh 1992 and Smith et al. 1995).
Cooking allowed us to save much energy, which could then be used for higher cognitive abilities. Without cooking, it is likely that our brain would never has gotten to the size it has today. Our brain consumes about 20% of our energy today (which is very unusual if you compare to other species). Cooking therefore also lead to an increase in brain size.

It is a pretty common claim. It was easy to find evidence. I added two papers and a book as reference in the text. Thanks

Almost all the muscle groups around the eyes nose and cheeks are primarily for communicating, so the face has developed into a communication organ, it is a highly varied organ with more muscles than the hand. 43 muscles in the face, and 34 muscles in the hand. Mostly the facial muscles are unconsciously triggered by emotional states, not by physical necessity. Our subconcious also reacts faster and more primitavely to facial emotional expressions than it does to logical processes that require concious awareness and reasoning. i.e. when a human sees an angry face in his peripheral vision or centrally, his nervous system reacts faster than he can actually turn his eyes to observe the face directly, and he will become aware of the fact after he has reacted.
The human climate range and population size is huge, so the differences are on par with other primates that have divided 2500 grandfathers (generations) ago, we have very distinct populations from Australia to Africa. Secondly, humans have selectively bred with non-human species such as Denisovan and Neanderthal species. Bushmen are not part Neanderthal, and Papuans are part Denisovan, and the rest of us have neanderthal genes.
Primates have a tendency to develop facial display features, faces are more important for primate communication than in felines for example. many primates also have bald cheeks and chins, which is uncommon for mammals. We have bald faces and more muscle groups in our face than many other animals.
Primates have red, blue, pink, white, colors on the face, mustaches, maturation protrusions, whereas felines, squirrels, bears, don't often have face specific displays, perhaps camouflage, except for example the lion.
2-3 of the animals at the end are not primates, see if you can guess which ones:

One theory suggested by my human ecology professor at Oxford posits that 4 legged primates communicate sexually by displaying and looking at each other's sexual organs, because they are at the same level as the head.
The theory states that humans use strong eye and face contact to communicate sexually, instead of smelling and so the mouth has come to symbolize the sexual organs in communication, and so have other facial features.

The most unusual features of the human face on a purely visual basis is our nose and our chin.
OUr chin has been hotly debated I know of no less than five separate hypothesis about its development. The leading idea based on current evidence points to the chen being a side effect of our shrinking faces and therefore jaws at the same time we are increasing our reliance on speech, the need to keep the the jaw braced at the same time we did not 'want' our throat or tongue to be smaller, the chin is a side effect of how the jaw grows under these constraints in early  development. Oddly fetal chimps have something similar to a chin.
The nose is a bit easier it appears to be a response to our ancestors both growing larger brains (pushing the sinus forward) at the same time we are moving into drier climates, the nasal passage keeps the air you inhale humid enough to not damage your lungs. So the nasal passage needed to be larger (or at least not get smaller) at the same time the face is getting smaller and the brain is squeezing out the sinuses. The solution is a protruding nose.


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Recent research in bioluminescence powering photosynthesis?
In 2013 there was a Chinese study published on "Bioluminescence as a light source for photosynthesis," which is briefly summarized in this Chemistry World article. There was a question on Biology.SE about a year earlier asking about the feasibility of such (and a somewhat related question for photovoltaics also in 2013).
My question here is if there is any newer research in the area of bioluminescence powering photosynthesis? Bonus if it is even more specifically related to any kind of crop production (so on a larger scale).
Please note:

I am not a biologist (last biology I took was AP Biology in high school a number of years ago).
From the other answers here on Biology.SE, I understand there is inefficiency with the use of bioluminescent light for "powering" things, but I'm still interested in more theory behind it as related to photosynthesis (hence the question about any newer research) for purposes of a fictional work I'm pursuing where sunlight is not an option. As a side question, imagine a "sky" of bioluminescence; would that be enough to grow some level of crops or trees?

Consider conservation of energy: where does the energy for the bioluminescence come from?

@jamesqf Well for purposes of the main question here, from wherever the sources for the bioluminescence get their energy from based on whatever particular source a recent study experimented with. For purposes of my side question for my fictional work, an animal that primarily "feeds" off geothermal heat (of which it has an unlimited supply to feed off of). While that part may be a point of "suspension of belief" in my story, I want to figure out if "reality" confirms that some size/level of normal Earth plants could be grown by the bio-light assuming enough light is generated.

Well, there's physics again :-(  Thermodynamics, this time.  You can't simply feed off heat, you need a temperature gradient.  But assuming you have some way of generating bioluminescence that's strong enough, and of the right spectrum, you can grow plants.  It's no different than using LED grow lights for house plants: https://www.gardeners.com/how-to/gardening-under-lights/5080.html  But the natural bioluminescence I've seen is far too weak.

@jamesqf I'm not sure I follow what you mean by "a temperature gradient" with respect to the feeding, other than are you saying the rate the heat flows into the animal? But this question is not about that aspect. So theoretically, if the bioluminescence was of an intensity/duration equal to an overcast day, then most plants (except perhaps those that really like direct sunlight) would grow fine (if I understand you). The fact that it is bioluminescent light vs. sunlight is not directly a factor on photosynthesis.

By temperature gradient, I mean there has to be a difference in temperature in order to extract energy - just as a rock won't roll downhill if it's on flat ground.  WRT photosynthesis, yes, as long as the light has enough energy and the proper spectrum, the plants don't care where it came from: http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/ligabs.html

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What measurement can demonstrate whether someone has decompression illness?
My understanding is that DCI occurs due to nitrogen bubbles forming in the blood when a diver ascends from higher to lower pressures. DCI typically occurs once these bubbles are large and/or numerous enough.
Dive computers typically run one of these algorithms to estimate how your tissues will uptake and release nitrogen whilst diving to ensure that you probably don't get DCI.
I'm wondering if there's any physical measurement that can be performed which would directly assess the bubble load of your tissues?

Physical measurements during an ascent or experimental? I'm unsure of what good it would do, as it would seem physical measurements would be impeded by a diver's gear, but I don't dive, so...

@anongoodnurse - Well, I was hoping that there would be a test that's generally carried out in a hospital that might be possible to carry out during ascent as well given equipment designed for it

Apparently, bubbles in the heart can be seen on an ultrasound: https://dan.org/research-reports/research-studies/exploring-decompression-bubbles-using-advanced-ultrasound-techniques/. However, this only correlates with DCI, and can't diagnose it. In the field, DCI is diagnosed using signs and symptoms such as joint pain. (I am not a medical professional)

Researchers have been exploring various imaging techniques and monitoring methods to detect or quantify gas bubbles in tissues: Ultrasound Imaging, to detect and monitor gas bubbles in divers tissues post-dive to check for larger gas emboli within blood vessels or organs. MRI for detecting microbubbles or regional differences in tissue perfusion due to gas emboli formation. Transcranial Doppler Ultrasonography to assess changes in cerebral blood flow velocity as an indirect measure of potential arterial gas embolism affecting brain circulation. Transthoracic echocardiography to evaluate venous gas embolism by visualizing bubbles passing through the heart chambers. Gas Detection Devices (portable breath analyzers) to measure nitrogen levels exhaled by divers which could provide some indication indirectly about their body's saturation level. Electrical Impedance Tomography to detect bubbles in the lungs.

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Can you have a higher nitrogen load in your tissues after travelling over a hill?
This question has spawned from a discussion between myself (a novice diver but an engineer), and a diving instructor.
The training materials indicate that if you (having not dived yet) are driving and go from sea level, to an arbitrary higher altitude (assuming the gas mix remains constant), and then return to sea level after a short period, it is possible to have more total dissolved nitrogen in your body than when you started your ascent from sea-level. Which would indicate that your blood/tissue has become super-saturated with nitrogen going from a lower to a higher pressure.
My understanding tells me that this is impossible.
When you start ascending (higher to lower pressure), you become super-saturated as the solubility of nitrogen decreases at a lower pressure. This causes you to off-gas and lowers the total amount of nitrogen in your tissues until you reach the saturation/equilibrium point of the higher altitude (or start descending again).
When you're descending on the other side, the solubility of nitrogen increases, so you're no longer saturated and your tissues take on more nitrogen. This process continues until you hit your bottom altitude (sea level) and eventually become saturated at that new altitude.
As such, on the other side you should have less than or an equal amount of dissolved nitrogen as where you started.
Plotting altitude, pressure, and dissolved NO2 against time on a graph by my reckoning should give you something like this.

Now, this guy is far more experienced at diving than me, and this isn't my field of expertise so am I missing something or is the training material mistaken?
I originally asked this question over on Physics SE and recieved a rather speculative answer that this might have something to do with adsorbtion but was advised that this is probably more of a biology question than a physics question, so I'm looking for a more confident answer.

Your understanding is how I understand it too. I think they are conflating the "don't fly after diving" rule with nitrogen absorption. The partial pressure of N2 at altitude should be less, so there should be less in your blood is how I understand it. Dalton's law. However, there might be a biological mechanism I don't know about at play here.

@JiminyCricket. - It could reduce your no deco time for your first dive potentially, but it's not a huge difference. I guess my main issue is that I want to understand why the process we're being taught works and unless this is definitely a mistake, then I don't understand it and have a gap to fill

What training materials are you referring to? Can you link them and/or quote from them?

It's the BSAC training materials. I don't believe that I'm allowed to share them. I have paraphrased the section in question though. There's a transfer diagram where you start at a Tissue Code A,  go up a hill taking you to  a tissue code B, return to sea level still at a tissue code B

After a lot of discussion with my diving officer, we've agreed that the following might be true. I'm not going to accept this as an answer until I've had some affirming opinions though.
The diagrams in the answer are accurate when considering purely the nitrogen that is actually dissolved in tissues/fluids in your body.
However, what it doesn't consider is that when you first ascend, you will have formed (micro)bubbles of nitrogen in your tissues. These may not have had time to actually escaped from your tissues by the time that you descend again. Once you have descended again, there's also no guarantee that these bubbles will have been broken down/re-dissolved. So, whilst your dissolved nitrogen load will be less than or equal to before you went over the hill, you may still have extra bubbles in your tissues.
This lowers your no-deco time for your next dive because it would take a smaller number of bubbles (as they are being added to the already extant bubbles) to increase your risk of DCI unacceptably than had you not already had these residual bubbles, regardless of the actual amount of dissolved nitrogen.

As I understand it (but probably a gross oversimplification), gases in equilibrium with their dissolved forms may come out of solution and form bubbles upon a sharp pressure decrease.  These guys seem to think it can occur with nitrogen at  high altitudes.

@user338907 Yes it can occur at high altitude, but only if there is a relatively sharp depressurization event - going up in a non-pressurized plane for instance. I think driving wouldn't count here as the ascent/descent is so slow.

@ScottishTapWater This also doesn't make much sense to me. The bubbles would be pressurized by diving and become smaller, therefore dissolve more quickly into the bloodstream/tissues. I could see that being a problem if you were nitrogen saturated and the bubbles couldn't dissolve, but I think driving would be too slow to cause bubble formation.

Normally the proportion of nitrogen does not change perceptively with altitude/depth.  Divers tanks run off compressed air usually, so the composition doesn't change.
Altitude doesn't change the gas composition. The effect above water surface is small since the entire pressure range is just 1 atmosphere, several atmospheres in an extreme dive. (34 ft -> 1 atm).

Our atmosphere contains approximately 79% nitrogen and 21% oxygen, a constant ratio until you reach an altitude of about 270,000 feet.

FAA Airmen Education
The solubility of nitrogen comes from the partial pressure of nitrogen (usually a constant) from the gas breathed. Which does not produce bubbling in the blood for quite a while. So ascending altitude is similar to coming up from about 30 feet depth. The nitrogen degassing is there but it does not create decompression sickness.  Not suprising, land animals are acclimated to pressure changes of up to 1 atm.  It makes you think about diving ocean mammals and birds who can go down 120 or more feet in depth.  They have adapted so that decompression is not an issue for them!
its the total pressure in the blood.  above sea level

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Enhanced Spectrum Chloroplasts
As far as I'm aware, chloroplasts produce energy through the use of photosynthesis which essentiall converts CO2 and Water into Glucose (I'm an engineer by trade so really wracking my brains to the last time I studied biology formally).
The pigment in chloroplasts, chlorophyll, makes the plant appear green due to the fact that it absorbs red and blue light, reflecting the green.
My question is this, would it be possible to extend the light spectrum absorbed by the chloroplasts, perhaps through the use of very careful genetic engineering and manipulation of the pigments contained within, in order to increase their energy absorbtion rate.
In essence, could you could make them absorb a wider range of frequencies for use with photosynthesis and thus enable much faster glucose/ATP synthesis?
If this were possible, how much of an evolutionary advantage would it provide?

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What is the current consensus on the Loveheim Cube of Emotion
I recently encountered the Lovheim Cube of Emotion. I was wondering what level of supporting research there is to go with it and whether or not there is a concensus at this stage.
If I'm perfectly honest, I'm skeptical, the evidence that I've seen is uncompelling and the model over simplistic but maybe I've missed something.

What research have you done into this, and can you tell us what you found? Your link states, "While the validity of the model remains unverified ..." Thanks.

That's part of the problem, barring that wikipedia page I've struggled to find any scholarly resources discussing this in any depth. I tend to take wikipedia articles with a strong pinch of salt since they rarely represent active research very well.

@JamesHughes What about the resources cited on the wikipedia page, and all of their citing articles? This isn't my area of expertise within neuroscience, but from a very cursory overview it seems like it has gotten a lot more traction in models for artificial emotional systems rather than explaining actual biological emotion; I suspect this may be partly because there is no spatial component. The monoamines are not hormones in the nervous system, they are neuromodulators or neurotransmitters, so spatial components matter a lot. Simplifying it to a cube based on concentration ignores space.


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genetic difference subpopulations vs movement rate
Someone told me that if a geneticist finds no significant difference between 2 subpopulations that have temporal spatial overlap it might be that they are still almost closed (no connection). Is this right?
Can I deduce anything about the individual exchange rate between populations and the genetic similarity/difference? For instance, one would need 5% of individuals to switch populations to keep them almost genetically identical. Does this differ between species (let's say fish and mammals)?
Thanks.
ps: any references to this would be great

[..] if a geneticist finds no significant difference between 2 subpopulations that have temporal spatial overlap

This isn't clear. Significance difference between what? What statistical hypothesis are you testing for which one would found no signicant difference (accepted the null hypothesis). Are you maybe thinking about a t-test between testing difference between the average phenotypic traits?

it might be that they are still almost closed (no connection). Is this right?

Do you mean no gene flow (aka. no migration)?

Can I deduce anything about the individual exchange rate between populations and the genetic similarity/difference?

"Individual exchange rate" is typically "called migration" or "gene flow".
At some extend, yes you can. But the question is really broad and will be hard to answer in the general sense. I will just provide a very common methodology here.
You can compute $F_{ST}$, a statistic of population divergence. A very good paper explaining the math of $F_{ST}$ is Nei (1973). I recommend computing $F_{ST}$ following Weir and Cockerham (1984). Then, if you can assume a finite island model (equal migration rate $m$ between any two population) and a constant and known population size $N$, then
$$F_{St} = \frac{1}{1 + 4N(m+\mu) \frac{d}{d-1}}$$
, where $d$ is the number of demes (number of islands)This equation can be found at many places. Slatkin (1995) is a very good paper but note that its final solution differs a little bit from the one I presented (by a square term) for reasons explained in Charlesworth (1998). You can solve for $m$ and plug the observed $F_{ST}$ and $N$. Note that depending on the markers used, $\mu$ will be negligible in comparison to $m$.
You might want to have a look at the very related post How could one calculate the gene flow between two populations?

@Wave Did it answer your question?


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Does ribosome associated with RER separate from RER after finishing protein synthesis?
After ribosome associates with RER because of its specific signal sequence, and then when cotranslation translocation is finished, does ribosome return to free floating ribosome at cytosol? Or does it stay as combined condition?


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Where did H2 come from at pyruvate oxidation?
After pyruvate oxidation, H2 come out by pyruvate dehydrogenase. Does this mean H2 is from C3H4O3 (pyruvate)?
But then it makes no sense that numbers of pyruvate (C3H4O3) 's H and acetic acid (C2H4O2) 's H is same.
How can this happen if H is from pyruvate?

It's not clear what enzymatic reaction you mean, but since you mention acetic acid, I would guess it's the quinone-coupled pyruvate dehydrogenase (EC 1.2.5.1, also known as pyruvate oxidase). It would help if you write out the entire reaction.


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Is there any difference between hydrogen acceptor and hydrogen carrier?
As what i have learnt, hydrogen carrier (NAD+ and FAD) gets H (H+ and e-) from glyceraldehyde 3 phosphate dehydrogenase or Pyruvate dehydrogenase, and then transport H to electron transport cycle.
Do NAD+ and FAD act as hydrogen acceptor, hydrogen carrier, electron acceptor, and electron carrier?
Does this mean hydrogen acceptor = hydrogen carrier = electron acceptor = electron carrier?

Actually, both NAD and FAD accept a hydride ion, H$^-$ (a proton with two electrons), not a hydrogen atom (a proton with one electron). For this reason, I would not refer to NAD or FAD as "hydrogen acceptors" or "hydrogen carriers" at all. It just gets confusing. (I guess you could call them "hydride acceptors" if you want, but it's not common terminology.)
"Electron acceptor" is the right name for NAD and FAD when discussing a redox reaction where they in fact accept electrons, in the form of an H$^-$ ion. Pyruvate dehydrogenase which you mentioned is one such example. This is not unique to biology, it's standard chemistry terminology: any molecule that accepts electrons in a redox reaction is (cleverly ;-) called an electron acceptor. For example, oxygen is an electron acceptor in combustion reactions. So "electron acceptor" is just a name for the role that the molecule plays in a redox reaction.
"Electron carrier" refers to the fact that NAD (and also NADP, and quinones, and some cytochromes ...) can carry electrons between reactions that occur at different places. For example, after NAD picks up an H$^-$ ion in the pyruvate dehydrogenase reaction to form NADH, it can carry the two electrons over to complex I where it donates them to ubiquinone. (And here, NADH acts as an electron donor, while the ubiquinone is the electron acceptor.) So the term "carrier" emphasizes the transporting role of the molecule. FAD is actually a bit different in this respect, because it is not soluble; it's a prosthetic group bound to certain enzymes like Complex II, and therefore it cannot really carry anything anywhere, or at least not very far. So to be precise, I personally would rather not call FAD a carrier. But maybe that's just me.


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What is this New Zealand insect and what is it in?
What kind of insect is this?

Found in Early September at Jubilee Park, Dunedin, New Zealand. It was suspended from a silk thread (quite long, a few meters) to a tree above. It was climbing the thread, balling the thread as it went up. It looks like a caterpillar. What species is this and what is it inside of?


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"Twig-with-leaf"-like insect in central Mexico
What's that?! I have googled around and found insects that looks like a twig, and others that look like a leaf, but this one looks deceptively like a leaf at the end of a twig (I swear it's a real living thing despite the appearances: it has legs and moves around!). As you can see from my hand on the photo it is also fairly big (well, at least for my European standards...).

Location: Morelia, Mexico (about 2000m high, in the tropics)
Time: October (humid season), in the morning

And about your European standards: the European praying mantis is up to 9 cm and occurs all over Southern Europe and even at isolated locations in Germany. See Though I admit I was startled too when I encountered one.


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Is Circle of Willis unique to humans?
I understand that Circle of Willis is a circulatory anastomotic system that provided blood to the brain.  I want to understand if this system is unique to humans or does it exist in other species or mammals to be more specific?

This is very trivial - it's a one word answer, no. I got my answer by go ogling "circle of willis dogs" hence closing as poorly researched.

I agree that the question could have been rephrased in a better way. Also, 90% questions here can be googled. It's more about getting pointed in the right direction - to publications and established research.

See the help pages on writing good quality questions

I found two references that talk about the circle of Willis in different kind of mammals so i think it's right to say that this particular anastomotic system of arteries is not exclusive to humans.
Here are the two references:
http://www.neuroanatomy.org/2008/054_065.pdf
http://www.ncbi.nlm.nih.gov/pubmed/14651482


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What is variation in Speciation
I read a lot about speciation. To my knowledge, a species is often defined as a group of individuals that actually or potentially interbreed in nature and produce fertile offspring. Speciation is a lineage-splitting event that produces two or more separate species.
Now, some creationists claim that there is no speciation, rather variation in the same species. As in "fruit fly experiment", I read that two groups of fruit flies don't interbreed after the evolution and speciation takes place. As per the definition of species (biological concept of species), they are supposed to be two separate species (reproductive isolation). Nevertheless, creationist claim they are still fruit flies and there is no speciation. They say that's just a variation in fruit flies, not speciation. I can't understand their claim.

Voting to close because this is a question of semantics. You both observe the same phenomenon and are arguing over which word to describe it. Whether you call it speciation or variation, the event still happened.

you should probably go to reddit with this question - they are more focused on handling such questions and dealing with the interface of the general public with science there.

@canadianer variation and speciation have different meanings. Tanvir, you should clarify where you have actually seen this usage; it would be easy for us to check the authenticity of the reference. Basically, variation is a general term to describe genetic and phenotypic variability whereas speciation, as you have indicated, has additional constraints.

@WYSIWYG Even after re-reading the question, I can't quite remember what point I was trying to make, but you've certainly missed it ;)

You are asking explanations about a creationist argument. One could provide explanations about some hypothesis that you may found in a science paper but not explanations for a creationist argument just because, by definition, a creationist argument is not supported by any evidence and logical thoughts. However, you may want to link to a creationist website making a specific claim of interest and we may eventually talk about whether the claim is wrong/misleading. It would be very handy to have the claim in quotes rather than an explanation of what the claim is.
You say

[..] after the evolution and speciation [..]

This piece of sentence sounds weird. You could say after the evolution of something (meaning the appearance of this something through evolutionary processes that are mutations, natural selection, drift and eventually others) but just "after the evolution" sounds as if evolution may not exist during some periods of time.
Talking about speciation in fruit flies, you will likely be interested in reading this post.
UPDATE
In general, when talking about fruit flies we talk about the Tephriditae. Tephriditae is a family of flies which contain about 5000 described species (including the model organism Drosophila melanogaster).
So, there is definitely different species of fruit flies. Of course, within any population (to the exception of populations of exact clones by definition), you have variation. This variation is a key concept in evolutionary biology. If this is unclear to you you may want to learn a bit more about evolutionary biology, including the concept of heritability ($h_N=\frac{V_A}{V_P}$).
Speciation took place in Tephriditae (otherwise we wouldn't have the species we have today) and is still taking place. The post I linked above gives an example of speciation between lineages of Drosophila melanogaster that has been directly observed in the labs.
Your issue seems to likely be a semantic one. As there is variation within a lineage and this variation is associated with groups that are in reproductive isolation, then the two lineages you consider do not belong to the same species anymore. Therefore, there was a speciation event.

Actually, I do belive in evolution and I m an atheist. When I raised the fruit flies case to a creationist , he said, they are still fruit flies and there is no speciation. He said thats just a VARIATION in fruit flies, not speciation. But I cant find any logic there. IS IT SO ? He alwasy links VARIATION to SPECIATION case. HE says there is never SPECIATION taking place, its just a VARIATION in the same species.

I added an UPDATE to my answer. Let me know if this answers your question.

Thnk u very much. I m grateful. I got the same understanding as u mentioned. But I think creationists dont know the meaning of species.
One more thing, he said, he doesnt want to talk about insects in this context, since it creates some problems , such as- 1.Anachronism 2. Grandfather Paradox . What are they, How on earth are they related to speciation ?

I never heard of the concept of anachronism in evolutionary biology and the grandfather paradox is related to time travel, so it definitely has nothing to do with evolutionary biology.

He said- The slow changes in traits in organisms taking tens of thousands of years to yield a visible change in variation as you suggest, does eventually trap yourself in to a problem of "Time Riddle" - you just dont have enormous enough of time at hand for all these species to come into being. A quick average time calculation suggests that you should have a new species come into being every 15-20 yrs [just rough average time estimation suggests that in about 1 billion yrs ~50 million distinct species evolved]. Don't just start with punctured equilibrium now. You just cannot have it both ways.


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How to validate the use of an anti-virus monoclonal antibody in IHC by spiking a fresh organ with infected cultured cells?
I have assessed the specificity of a particular monoclonal antibody against a virus by immunofluorescence. I'd like to further validate it by testing it by IHC. Therefore I'd like to infect cells in culture, and then inject them in a piece of fresh organ, fix in formalin, embed in paraffin and then cut slides before performing IHC. Is there any protocol or references to do so ?

Injecting into a fresh organ seems like a needless complication if you're just validating your antibody and not interested in gathering data about the interaction between the cells and the organ. (In fact, if you're using anything more complex than a flatworm I'd hope your IRB would have problems with needlessly sacrificing animals to get those organs.)
It seems like your purpose would be better fulfilled by making an FFPE cell plug and doing your IHC on that. Here's a protocol for making cell plugs:
Johns Hopkins Tissue Microarray Lab Cell Plug Protocol

Thanks you for your answer. Actually this was a request from a reviewer. Regarding organs I work close to the vet necropsy department therefore getting fresh organs is not an issue.


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Where does oxygen come from in winters?
Since plants shed their leaves and don't perform photosynthesis during winters, where does oxygen come from?

1-There is a lot of oxygen. Certainly enough to last the winter. 2- Equatorial rainforests don't lose their leaves as the seasons are less severe. 3- The Taiga forest in Russia and the Boreal forest of Canada have evergreens which also do not lose their leaves.

4 - Generally "winter" is not "winter" at the same time everywhere on the world.

Oceans are the largest producer of oxygen

As others have pointed out, it's not winter everywhere at the same time, and there's a lot more oxygen than would be used up in one winter.  However, if you look up "Keeling Curve", you can see the annual variation in CO2 (and hence O2, inversely) due to winter in the northern hemisphere.  It seems to be on the order of 6 ppm.

These all look like answers to the question.


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Negative Phototropism In Plants
Why does the root of a plant go away from the sun? The shoot goes towards the sun, why does the root go away from it?

What do you think would happen to the direction the roots would grow, if the light source was below the plant?

@GabrielFair I don't know sir thats why I am asking the question. If I were to guess, it goes away because it wants water and sunlight evaporates it.

can someone please answer

All you have to do is read the wikipedia page for phototropism. https://en.wikipedia.org/wiki/Phototropism

The roots respond to gravity, not to light.  They display what is called a geotropism (aka gravitropism).  It has nothing to do with the light..  The roots grow TOWARD the force of gravity so the roots exhibit positive geotropism.   The stem grows AWAY from the force of gravity so it exhibits negative geotropism.   Think about a tree planted on a hill.
Phototropism is a plant's response to light.  It has nothing to do with the direction of room growth.  The stem may lean toward the sun (because of it's positive phototropism) but will still grow upward because of its negative geotropism.
**If the light was below the plant, the roots would still grow downward.

This is a good answer, though we prefer answers here at Biology.SE to include some citations to support statements and encourage further reading.


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What biotechnology can be used to treat lazy eye, and possibly cure lazy eye?
I tried very hard researching and finding the root cause of amblyopia. It is mainly because of imbalance in eye muscle. But, there are a lot more complicated causes of this disease. Thus, I need some help in finding a biotechnology for treating lazy eye.

I wish anyone could provide me a little clue.

Is it Graves disease cause by a thyroid problem ?

That's an extremely well documented subject on the net. there are even pages by doctors about it.

In order to treat amblyopia you first have to treat the initial problem with the eyes that caused it, which is a medical issue and probably not what you are asking anyway. However, as wikipedia states, "after the underlying cause is fixed, vision is not restored right away, as the mechanism also involves the brain."
As a rule of thumb anything related to brain functions (in humans) is so complex that we don't really have the (bio)technology to just cure it. Sure, their are some advancements in a few areas, but especially if you want biotechnology to do this, you'll probably have to wait at least 10+ years for a medically save and readily usable method.


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Is it possible to have life that feeds on thermal energy
On earth, as far a we know, there are two main ways that bacteria gain energy.
First, there is Photosynthesis, the transition of light into chemical based energies such as ATP.
Second, there are chemical processes in which the cell breaks down a variety of molecules down to gain energy from the reactions. A example of this is Chemosynthesis.
Is it possible for their to be a bacteria or type of organism that gains energy from thermal energy?
For example, there could be a bacteria that lives in a volcanic area, somewhere hot enough that there is a excess of thermal energy. Would there be a way for such a cell to use this thermal energy in much the same way that some cells use Sunlight in Photosynthesis?

It's a good question! You might take a look at how systems like heat pumps, thermoelectric generators, coal/gas/nuclear power plants or even cars get energy out of high temperature. They all have a hot end and a cold end, and extract work from the movement of heat from one end to the other. If you are in a uniform temperature, it's hard (impossible) to use it effectively.

It is theoretically possible but no known organisms does it. The problem is you need a pretty strong and persistent temprature gradient to generate usable work out of it, and those are not that common in nature.

Heat is probably the most inconvenient pain-in-the-behind energy source to use (as bacteria). Main reason is that you have to harvest it as it moves across a membrane/gate, and then the cell or whatever has to be built to handle the temperature on the other side.
Even worse: as the bacteria harvest heat, they will end up the same internal temperature as their food source, requiring them to move somewhere and cool off (infeasible for bacteria).
A somewhat viable theoretical example: highly mobile partially amphibious reptile that lives in a beach-type environment in tropical climates. It would harvest heat while basking on the sand and jump in the water to cool off. Energy harvesting occurs as heat moves across the lizard's hide outside to inside. The harvesting is 1-way: cooling off doesn't cost energy.


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What kind of spider is this?

Found in my house in a Beltsville Maryland

It looks like a brown recluse spider

I disagree with Trachelas.  Two points stand out for me - the chelicerae are forward-projecting, rather than the flat face of the sac spider; and the rather odd knock-kneed appearance of the front pair of legs is a bit unusual for Trachelas.
There is another two-toned, red-and-tan spider that also turns up in houses in the spring and fall - the European import Dysdera crocata aka the Woodlouse Hunter.  That's what this is, I believe.

I agree with Dysdera crocata from the generally-longer shape and because of the shape of the chelicerae


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can anyone identify this plant please?
Seen in the med and have it in my garden

It is a houseplant, not a common wild plant. Your question might be a better fit on gardening.SE.

This flower is some type of mandevilla.

The question states "seen in the med" which I assume means the Mediterranean.


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What are the chemicals of betel leaves that may react with estrogen?
Im conducting this experiment about pregnancy testers.Im not quite sure what extract method i can use regarding this experiment.any thoughts?? please help me..


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Do common terms for animals such as amphibian or reptile fall somewhere in taxonomy levels?
Where in the "ranks" of taxonomy (domain, kingdom, phylum etc.) do common words used to describe animals such as amphibian and reptile fall?

This is all a matter of how we define terms, and which definitions are scientifically useful.
Traditionally (since Linnaean times), organisms were classified based on their outward similarities (phenetic systematics). As such, the traditional definition of reptile, which is the same as any common usage that I've heard, includes organisms like snakes, lizards, turtles and crocodiles but does not include birds. This is the class Reptilia. As evolutionary understanding increased, however, it was found that some reptiles, like crocodiles, are actually more closely related to birds than to other reptiles. This makes the common use of reptile a paraphyletic classification.
In modern phylogenetic systematics, organisms are classified in monophyletic groups, or clades, that include an ancestor and all of its decedents (ie it is based on evolutionary relationships). Thus the class Reptilia, since it is paraphyletic, is essentially meaningless in this system. In order to have consistent nomenclature, you could either say that birds are reptiles (a new, cladistic meaning of the term, but which contradicts traditional/common usage) or come up with a new name that includes all traditional reptiles and birds. Taxonomists taking the latter approach use the term Sauropsida for this clade. Sauropsida does not have a taxonomic rank like class because such ranks are useless in cladistics (and actually quite arbitrary even in the traditional system).

So, to specifically address your question:
In phenetics, both Reptilia and Amphibia have the taxonomic rank of class.
In phylogenetics, what we commonly consider reptiles and birds are grouped in a single clade that can be called Sauropsida or Reptilia (re-defined to include the clade Aves) depending on who you ask or which paper you read. Amphibia form a clade.
Perhaps the most important take-away message is that taxonomy is largely un-standardized.

Actually phylogenetic nomenclature is extremely well codified: https://www.ohio.edu/phylocode/ (some would say too much so).

@kmm I'm not a taxonomist, but as far as I know PhyloCode has not been widely adopted. Even though standards do exist, taxonomy as a whole is not standardized (at least not well). That said, I can remove the last sentence if you think it is misleading.

Amphibians form a class in phylum Chordata.
Reptiles, when considered as a taxonomic group, are also usually seen as a class in phylum Chordata. However, some scientist don't see reptiles as a valid taxonomic group because they are not monophyletical and modern taxonomy tend to accept only monophyletical groups.
That is, according to the taxonomy I was taught at school some decades ago, fishes, amphibians, reptiles, birds and mammals where classes in phylum Chordata. Nowadays, it is known (and stressed) that some reptiles are evolutionary closer to birds than to some other reptiles: there were common ancestors of crocodiles and birds that weren't ancestors of turtles.
Since monophyletic groups are defined as all descendants of a common ancestor, reptiles defined in the usual sense aren't a monophyletic group because they don't include birds. Therefore, some taxonomist either expand reptiles to include birds (and then "birds" and "reptiles" can't be both classes, although remaining valid) or just discard reptiles as a valid taxonomic group.
In the other hand, extant amphibians seem to descend from a common ancestor, and therefore they aren't questioned as a valid class.
Interestingly, fishes, regarded as a class for long time, are also being questioned as a valid taxonomic group, since some fishes share a common ancestor with tetrapodes (terrestrial vertebrates) which is not an ancestor of some other fishes.

Evolutionary taxonomy is a ridiculous, nonsensical, complicated mess and we should go back to traditional morphological taxonomy (classification based on physiology, shape, and function). If it looks like a duck, quacks like a duck, and walks like a duck, common sense dictates that it probably isn't a reptile.

That's also a reason for some evolutionary to stop using reptiles as a taxonomic group instead of extending it: reptiles keep being useful as a word, just like "herptiles", "fishes" or "domestic animals", all of them useful although invalid in evolutionary taxonomy.

@user1258361 which works right up until you start dealing with extinct organisms in which modern notions grouping break down, where do you put pterosaurs, how about dinosaurs, how about feathered theropods. How do you deal with the fact crocodiles may be secondarily exothermic, or that turtles have lost their temporal fenestrae, hence the use of evolutionary taxonomy.

@John create new classes for those and group as normal instead of breaking existing terms that have been widely accepted for decades and remain well-defined according to their traditional definitions in common use. An article years back mentioned that dinosaurs ran on a spectrum between warm/cold blood, so you could well argue that they deserve their own set of separate classes.

so you have classes inside other classes inside yet another class inside yet another class, making the term "class" pointless. hence why ranks are being abandoned. Cladistics is still based on morphology just accurately compared morphology. Crocodiles share more features with birds than they do with snakes so why would you group them with the latter. PS there is no evidence for cold blooded dinosaurs.


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What evidence do we have that dinosaurs were mesotherms?
They went extinct millions of years ago, so what is the evidence supporting the claim that they were mesotherms? And are there any examples of modern-day mesotherms?

There are some examples in the Wikipedia page.


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Why do eyes change colour after death?
Why exactly do eyes turn black when we die? (Or even change colour at all).
The source of inspiration to this question is due to this video https://www.youtube.com/watch?v=6mNs_TcUyHc&t=627s (it's a cow's eye being dissected). The man explained how the cornea is crystal clear in an actual cow but since it's been preserved, the preservative has denatured the protein causing it to turn cloudy.
So why does our eye change colour when we die when no preservative is used?
I know this is a pretty gruesome question to ask but curiosity has the best of me haha.


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DNA extraction methods for hair?
TLDR: Can anyone state a extraction and isolation method(s) for genomic DNA for hair that will be used for PCR, in detail is preferable since I am a novice.
I tried googling for DNA extraction methods for hair(follicles and/or root) and found various sources, the one that had the most detail involved the use or organic compounds we do not have access to. Is their preferred method of extracting DNA from hair, given that the genomic DNA would be in low amounts, I figure that might have something to do with the extraction process.

Can you please give us some background? It would make answering the question easier.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0069588

@Chris          That was pretty much all the background there is, I am a undergrad novice who needs to extract DNA from hair for a proffesor's research. He sent me on this task as a way of self learning i believe, but I guess I am not "up to snuff", given my asking here.

@MattDMo        I saw that source, but i lack the powder(s) to do it.

@RoSiv When you write that you have no access to certain organic compounds without specifying what you can do, it is hard to give recommendations.

@Chris          This speaks to my ineptitude i suppose, I have no access to the phenol or chloroform and cant do the organic extraction method. I do not really want to either, given i have never worked with it before. I was hoping there would be a "simple" solution with alot of "common" lab ingredients.

I'm sorry, you don't have access to laundry powder? I find that very difficult to believe.

@RoSiv These are important informations that belong into your question. I am used to  work with hazardous chemicals (with the right protective equipment) as  this is part of my training. Nothing special about it.

@Chris               If I were to do the organic, phenol/chloroform extraction, would you have any advice or suggestions, sources/methods even?

I've been trying to figure out something that works for some time.  I have recently tried 3 cheap protocols using commonly available lab reagents.  I was using buccal samples (0.2 ml of spit).
1) Boil the sample in Tris EDTA Buffer
2) NaOH Extraction
3) Direct N Lyse
I compared them to a genomic DNA extraction kit (FAST DNA Prep - MP Biomedicals).
I have heard lots of people use NaOH extraction to get DNA from tissue and cell preps, but none of the first three worked for me after 2-3 tries.  One of the people in my lab said that I could replace the bead beater with vortexing with glass beads.
I tried vortexing with beads with all four methods, including the kit and only the kit worked.  I got a PCR result from control primers.
When you look at the costs of getting all the ingredients for the buffers kits are not so expensive - $1-$2 per sample.
A lot of these kits can handle solid animal tissues, though the one I have doesn't specifically cite hair.  I would try it out.
I guess the point of my post was that there are lots of simple sounding published methods, but they don't always produce results without a bunch of debugging.  I know alkaline lysis has worked for several people I know and is the basis of the kits.  Its pretty simple.
That's my experience anyway.

Awesome to see you active (you are one of two with 20k+ and full privileges after graduation :-) ! However, I was wondering if the buccal cavity contains hair, given OPs question?

Great, interesting, +1!


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Genetic Diversity in Mitochondria
As I was studying for my GRE exam, I was reading on Mitochondria. I then remembered that they undergo replication similar to bacteria. So I googled for info and found on Wikipedia that there is a " near-absence of genetic recombination in mitochondrial DNA"
https://en.wikipedia.org/wiki/Mitochondrion#Replication_and_inheritance
So then, if there is a lack of genetic diversity, how can these mitochondria still be functional? If we assume they are affected by random mutations as DNA can be. Is it the case that they replicate infrequently enough to not suffer ill-effects of low diversity?

Your claim that "there is a lack of genetic diversity" in mitochondria is not correct. There is no connection between recombination and mutation rates per se. In fact, mitochondria have much higher mutation rates than nucleus and different types of mitochondrial DNA can even co-exist in one organism, a phenomenon called heteroplasmy (which is found at a frequency of ~90% in human).
But: there is a connection between mutation fixation rate and effective population size. Because mitochondria are normally inherited through maternal line, effective population size for their genome is smaller than that of the nuclear genome, and thus any mutations in the mitochondrial DNA reach fixation faster, but again this is counteracted by high mutation rates.
There is no problem with functionality: as always if something gets broken (and it is easy to break something in the mitochondrial genome, since genes are normally tightly packed in it) respective genotype is eliminated or reduced in frequency by natural selection. In the case of mitochondria this selection acts both upon the level of individual organisms (intra-individual somatic pool of mitochondria: positive and negative selection) and the level of populations (mostly purifying selection in humans). It is nevertheless true, that given the virtual lack of recombination, selection becomes the only force of purging deleterious mutations.

Since mitochondria have a very small genome, with very little intergenic DNA, the mutations are likely to affect the essential respiratory genes (amongst others). Since many of these genes perform vital functions, many mutations may not be tolerated. I am not sure about it but would this also lead to loss of diversity? On the other hand, I had read somewhere that mutation rate in mitochondria is higher: perhaps due to high ROS concentration (my guess). Basically, how strong is the selection pressure against variation i.e. is there a sort of permanent bottleneck?

@WYSIWYG Yes, the fact that the mt genome is mostly coding reduces the potential allelic and nucleotide diversities in comparison to a randomly mutating sequence. And yes, mt mutation rates are much higher than in nucleus. Concerning the bottleneck: I've added a ref to a review. Nevertheless, there are always enough neutral mutations (3rd position and others) to contribute to the genetic diversity.

@WYSIWYG        Yea I guess I wasnt thinking about how important mitochondria are, and that a mutation would have to be purged out.


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Evolution home experiment?
If I were to take bakers yeast and put it in medium of minimal sugar(whatever quantity that would be) and rice(for a source of starch), could the yeast have a "evolutionary leap" and adapt to use the starch in its environment? I remember reading something similar in a report of E.coli bacteria and citrate adaption, under the heading:
 Catching evolution red-handed.
The passages in question are so:

"Every night, the bacteria run out of the sugar glucose and go
  dormant. The following day around noon, a researcher plunges a pipette
  in and sucks up 1% of the culture to inoculate a fresh flask. Those
  faster at gobbling up glucose will send more of their descendants to
  the following day's pipette and, after a few weeks, descendants of the
  fastest one will be the only ones transferred as the mutation 'sweeps'
  to fixation."

Under the heading: The rise of Escherichia erlenmeyeri, (bold emphasis mine).

"One morning, at the turn of generation 33,127 according to the lab's
  log book, a massive increase in turbidity was recorded on the vial
  labelled Ara-3. The sugar-starved bacteria had suddenly 'discovered' a
  vast new source of carbon by importing citrate, a pH buffer that had
  been in the growth media all along, and it sent the population size
  through the roof. "

So if I understand this correctly, there is evolution going on through the differential reproductive success of the bacteria, via their fitness which is affected by the glucose levels?
This "pressure" caused a type of "hopeful monster" in the form of Escherichia erlenmeyeri, the bacteria that could metabolize citrate, in which it didnt have the means to do so before.
So then could I replicate this concept with baker's yeast and starch metabolism and hope for similar results hypothetically? Or am I misunderstanding this?

You might also want to consider going with a molecular biology supplier... I wouldn't think that quality control on baker's yeast would be sufficient to be starting with a single strain, or have a sequenced genome.

Keep in mind that the citrate utilizing strain appeared after over a decade. Also, Escherichia coli could always metabolize citrate, but the citrate transporter that brings it into the cell is only expressed under anaerobic conditions [1]. The strain that evolved to import citrate under aerobic conditions had a duplication of the transporter gene which put it under the control of a different promoter that drives expression under aerobic conditions [2]. Baker's yeast doesn't have amylase or debranching enzyme genes [3], so a similar evolutionary mechanism cannot occur. Developing such enzymes de novo doesn't seem trivial, but perhaps the enzymes involved in glycogen metabolism can be repurposed. The only way to know is to try.

References:

Blount et al., 2008
Blount et al., 2012
Ostergaard et al., 2000


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Best method for measuring very young plant growth?
Is there a preferable method for measuring plant growth for a plant before the "sprout" stage? Preferably at the microgreen stage? I assume it would not involve some type of leaf based measurument, since they would have few, and maybe then should be based on mass or volume somehow?

I am assuming you want to monitor these traits in controlled conditions because in wild type conditions it will be real challenge to monitor in details unless you have easily accessible way (like leave surface area and related visual traits). Remember these techniques will change according to your plant/seed and your study interest. Lot of things change during development. You need to look at characters which suits your study. You can try following,

Monitor real time oxygen consumption in controlled chamber ( Generally researcher do this by monitoring loss of oxygen in
current chamber by some non invasive method. However there are
other techniques like this which can be also implemented
depending on type of plant.)
There are some automated image acquisition techniques like this or this
Use of volatile organic compound (VOCs) traces
Change is fresh and dry weight during development
Root moisture sensors ( in microgravity environment ) like this
I don't know whether you can use this kind of sensors in any way but these are very useful in monitoring particular element in vivo

This is very big list. There many other components which you can monitor like protein content, lipids etc. However such techniques are most reliable but destructive and you can use if you have large amount of samples.   You can go through papers cited in above list. Take a look at their methods and materials. You will know how to do such measurements and what are advantages/disadvantages.


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Bolyerine Snakes maxillary bone, split?
How is the maxillary bone split in the Bolyerine Snakes described in T.H Frazzetta's "From Hopeful Monsters to Bolyerine Snakes?"
In T. H. Frazzetta, "From Hopeful Monsters to Bolyerine Snakes?" He describes boid snakes on the island of Mauritius as being unique among snakes in that they had a split jaw, connected by a joint. This was said to be an example of how continuous evolution could not be true for all cases, as what is the point of 1/2 of jaw, according to Stephen J Gould.
I dont seem to understand the pictures illustrated in the aritcle though, and how the maxillary bone is split and where it is connected to a joint. I could not find a legible picture of a  Bolyerine Snake described like this, if anyone could help with understanding it with a picture that would be appreciated.
I would provide the pictures, but I am not sure if that counts as plagiarism.
Citation:
Published by: The University of Chicago Press for The American Society of Naturalists,
Available from: http://www.jstor.org/stable/2459073

What figure(s) are you having trouble with in the paper?

@kmm              I cant find the figures pertaining to the Bolyerine Snakes that label the "split" in the maxillary bone.

If you look at Fig. 2 in the paper, the bottom jaw has the split maxillary bone. Do you see how it says "MX" with two lines, instead of "MX" with 1 line on the top skull from Fig. 2? Each of those lines go to part of the split maxilla, with the joint being where it is pinched off (between teeth 5 and 6 on the drawing). There is also a CT image of the skull somewhere online that I've run across a few times (actually saw your question while looking for that image now).
I would also amend your statement a little in that it is not "as what is the point of 1/2 of jaw", it is that you can't have 1/2 of the joint(or split bone) existing. Either the maxilla is 1 piece or it is 2, but you cannot gradually go from 1 bone to 2 (similarly, either the cartilage of the joint exists or it doesn't. There can be a gradual change in how much cartilage there is, but if it's there or not is a binary question).
I hope that helps, off to look for the CT scan!

Nice answer - welcome to Biology.SE! The second part of your answer might be better as a comment on the question, which only asks about the interpretation of the figure.


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Learning industry skills for virology?
I am trying to learn more about virology for a tentative job I could be taking soon, as a quality control person in virology.
However, I have not taken a formal virology course, nor any course work in "quality control".
Googling showed me this website for learning more QC topics, however I was curious if anyone had better suggestions.
My question is if anyone had (ideally free) resources on learning virology (in the context of preventing cell culture contamination) and quality control in industry labs they thought would be ideal?

I work in human somatic cell therapies. For human administration I need to do, at a minimum, sterility and mycoplasma contamination testing (BacT/Alert culture bottles (Biomerieux), MycoTOOL RT-PCR (Roche)). For virally transfected lines I may need to QC the virus titer in the final product, and in some cases QC the transfection efficiency (qPCR, ELISA, flow cytometry). I also need to test viability, cell number, potency, purity and identity per protocol requirements. Perhaps first try to understand what the company you're applying to is doing for better direction.

@CKM.                I was speaking with a recruiter and they spoke on maybe placing me in a QC virology position because they saw I had some DNA extraction experience. They are going under a period of restructuring so I dont know if they have an official position open. From similar job listings of positions the sterility and Mycoplasma testing were listed as needed. The company is a mid sized bio tech that manufacturers; as they have / hire alot of production people for maintaining cell cultures ( I assume in large bio reactors).

I could probably recommend, then, an intro virology text at the undergrad-level if you're interested in the science. QC work is a lot of technical expertise. So not only should I know a bit about the test I'm running, but also the equipment, the results and how to analyze or report them. You learn none of it outside the job position, really. Important skill set will be wet lab experience, and being good with computers and recordkeeping (non-exhaustive list).

@CKM.                 I would like that very much. Thanks. And I am happy to take any other resource recommendations, maybe more info on the sterility and Mycoplasma testing?


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Do Red blood cells(mammals) really have no organelles?
I have read that mammal mature Red blood cells lack most organelles, including mitochondria, golgi apparatus and an ER. ( https://en.wikipedia.org/wiki/Red_blood_cell#Mammalian_erythrocytes ) This makes sense since there purpose is to transport oxygen via hemoglobin, and according to the wiki, they make any energy needed via glycolysis. But are there really no more organelles in a mature red blood cells? A simple google search did not help me.

Yes. This is true. During the final stages of red blood cell formation in the bone marrow, the nucleus and several other organelles are broken down and/or expelled from the cells. In the process they decrease markedly in size, from about 24 to about 7-9 micrometer. Presumably this makes them small enough to pass through the smallest capillaries. Lacking those organelles also limits their life expectancy to approximately 120 days.


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Binary fission in amoeba
When a parent amoeba undergoes binary fission, two amoeba are obtained. Are those two amoebas, both daughter, or 1 parent and 1 daughter?

During binary fission in unicellular eukaryotes ,the nucleus of parent organism divide into two it is followed by the divison of cytoplasm so two daughter cells of almost equal in size are formed

Binary fission is found in unicellular organisms like amoeba.After attaining an optimum size,the adult individual undergoes a simple division to firm two daughter cells of equal size. During this fission in amoeba,first of all nuclear division takes place followed by cleavage of cytoplasm into equal parts.

I think concept of parents and offspring (daughters) is not very useful for unicellular organisms.

In binary fission, the fully grown parent cell splits into two halves, producing two new cells. After replicating its genetic material, the cell divides into two nearly equal sized daughter cells. The genetic material is also equally split. The daughter cells are genetically identical (unless a mutation occurs during replication).

Source: Binary Fission - Wikipedia
This corroborates with what I was taught in school as well.
A quick Google Image Search also shows that most diagrams on the subject involve one parent producing 2 daughter cells.

But it doesnt make sense. The parent is still alive, how can we call it daughter?

From here "Fission is a process by which an unicellular organism splits(/divides) to form two or more new organisms.When the parent organism splits to form many new organism it is called multiple fission. If the parent organism splits(/divides) to form two new organism it's called binary fission. When this happens the parent ceases to exist and two new organism is formed. Amoeba reproduces with the help of binary fission."


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What digitally encoded smell formats exist?
Is there a defacto format for storing and transmitting smell digitally? Where can I obtain samples of such smell encodings? What reference dataset exists against which I can compare my smell sample to determine it might be the scent of an 'orange' or other scent?
There seems to be a lot of mostly theoretical material about how smell can be analysed, but little if any actual digital samples or reference data for conducting concrete experiments on that data.

hilarious tomd (for a 5 year old), only serious replies would be appreciated


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Why a brain's hemisphere controls the opposite side of the body?
As a physics student with very little understanding of biology, in a course about physics foundations diagnostic techniques I have come up with this question. I don't even know if it does make sense or not; in the latter case, please excuse me.
As far as I know, in the human brain the right hemisphere controls the motion of the left side of the body, while the left hemisphere controls the right side. Moreover, the part related to sight is on the back of the brain.
To me, it seems that there is a sort of opposition between the part of the body considered and the area of the brain that have to control it. Is this statement right? Only for human beings or also for animals? Are there any exception to this sort of pattern (if there is anyone)? Is there a logical reason to the fact that we show this characteristic and it couldn't be different from how it is?

See the linked answer, but a tl;dr is that this organization is very very old, as old as bilateral symmetry. In my opinion the best explanations are developmental ones, and the lack of any particular evolutionary pressure to untangle the connectivity. For most movements an organism makes, both sides of the body are involved. Even a reaching motion with one arm requires activation of postural muscles in the other flank to prevent you from tipping over, for example.

As far as exceptions, on the sensory side olfaction doesn't cross, probably for anatomical reasons (the olfactory bulbs are part of the brain and reach out almost to the nostrils), for vision the crossing is not by eye but by visual field: your left visual field from both eyes goes to the right side of the brain; also, since the image is flipped onto the retina, that means the left side of the retina stays on the left, and vice versa. Lastly, the cerebellum does same-side control: information to the cerebellum from the rest of the brain has to cross over before entering the cerebellum.

Another exception is hearing, the cochlear nerve enters the brainstem on the ipsilateral side and only downstream processing neurons cross the midline (and some descending projections from the cortex I believe).

"How" is easy to answer (signals from the right side of the body cross the midline and end up in the left cerebral hemisphere; answered well in a previous question). This pattern of wiring appears to have existed since bilateral symmetry first evolved.
"Why" is not a well-defined question; the possible evolutionary advantage gained by having cross-wiring is unclear.
To answer your explicit question: there is no "opposition" in any meaningful sense between the location of a sensory nerve on the body and the location at which the information is processed in the brain. There are a raft of visual areas in the neocortex, spanning from the back but extending forward. The areas that control eye movement are much more frontal ("frontal eye fields"). Before arriving in the neocortex, signals from the eyes pass through the dLGN, a nucleus in the thalamus which is a subcortical structure closer to the middle of the brain than the rear. This flow of visual information is similar across many (most? all?) mammals.


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How are viruses in vaccines weakened in a laboratory
I would like to know how viruses in vaccines are weakened or attenuated in a laboratory

Welcome to Bio.SE! Can You share what efforts you have done in finding the answer. Low-research effort questions are likely to be closed.

Short answer: You take viruses from humans and grow them in a different organism until it no longer elicits pathogenicity to human, through generations adapting to a different organism. Typically chicken embryos.

You can remove either the genetic material of the virus, or its functional proteins and then inject it.


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What is the name of this green plant with fat leaves with green color fruits?
Location: South India,Metropolitan
Year: 2017

It look like Almond tree, but small doubt not sure.


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What is the name of this yellow flower?
India, It was growing outside.
April 2017

Center part of the flower giving me Heebie-jeebies.

I think this is Cosmos sulphureus which is also known as yellow cosmos or sulfur cosmos. See the image (from here) as comparision:

More information can be found here and here.


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What species of snail is this?
I found it in Washington state, in a city south of Seattle. I found it next to a bush after it rained on someone's driveway. Here are two pictures of it:
( originally posted in instagram )

If anyone can identify this species, kudos to you.

where is the location?

@TheLastWord It's in the question…

If the answer below have answered your query, consider accepting it by clicking the green checkmark, giving you and the other user some reputation points. This aids in closing the question as solved. There is no obligation to do it either.

It resembles Cepaea nemoralis, or commonly called Grove Snail, belonging to the family Helicidae.

Image Source: WikiMedia Commons
According to Wikipedia, these snails were introduced to North America from Europe. These fascinating creatures occur in diverse forms of shell color as well, as shown below.

Image Source: Metodologie di Programmazione
Here I have found a very detailed shell and body markers for Cepaea nemoralis.

Image Source: ResearchGate


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Invertase calculation?
If I wanted to make $500\mathrm{\mu g}/\mathrm{ml}$ of invertase, from Sigma's Invertase from Baker's yeast, which states is grade VII, and greater than or equal to $300 \mathrm{units}/\mathrm{ml}$, then would these following calculations be right if I wanted $10 \mathrm{ml}$ of $500 \mathrm{mg}/\mathrm{ml}$ concentration of enzyme solution?
\begin{align}
M_1\times V_1 & = M_2\times V_2 \\
(300 \mathrm{units} ??)\times V_1 & = 10 \mathrm{ml}\times(500 \mathrm{units} ??) \\
V_1 & = 16.6 \mathrm{ml}
\end{align}
Therefore I need $300 \mathrm{\mu g}$ of the powdered enzyme which is equal to $0.0003 \mathrm{g}$ and add up to $16.6 \mathrm{ml}$ of sodium acetate buffer, to get my desired concentration of $500 \mathrm{\mu g}/\mathrm{ml}$?
Aside: And also, would this solution be able to be made in a day in advance and stored cold or would the enzymes degrade too much?
EDIT:
After reading the comments, googling, and looking back at old protocols. Is the following calculation below right then?
I need $500\mathrm{\mu g}/\mathrm{ml}$ as my concentration, therefore if I want $10\mathrm{ml}$ of my solution:
$$
(500 \mathrm{\mu g}/1 \mathrm{ml})\times 10 \mathrm{ml} = 0.005 \mathrm{g}
$$
Therefore, $0.005 \mathrm{g}$ up to $10 \mathrm{ml}$ of buffer.

I cannot find on the website where Sigma states that the enzyme concentration is 300 mg/mL, which isn't surprising because it is sold as a dry powder. They do say that it is 300 units/mg. You could make a solution with specific mass concentration, though that wouldn't take into account impurities, such as salts remaining from lyophilization.

you have units all wrong. do you need grams/volume or units, or what?

ps. Units are usually defined by activity. Like, 1 unit of enzyme converts X moles of molecules in 1 hour. So, more pure, higher-quality stuff will have more units per gram or per mole

@canadianer     Yes. I misspoke it was 300units/mg. How from that can I get 500 ug/ml?

@aaaaaa        I need 500ug/ml as my concentration. So would 16.6ml of buffer with 300ug of powder get me that concentration? Or if not, how would  I do the calculations? Thanks.

If you want 10 mL of 500 ug/mL sample, you take 5 mg of powder and 10 mL of buffer

@canadianer      I just saw your comment as I was typing. thanks. I guess what I was confused about was the 300units/mg that they stated. I thought that had some bearing on my calculation.

ok, but are you sure you want ug/mL as final concentration, not units/mL? I would suggest double-checking

@aaaaaa.         Yes that is what I need, thanks.


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method for DNA extraction for human mucus(nose) or earwax?
What is a simple method for extracting human DNA from nose mucus or earwax?
I tried googling for methods for DNA extraction for human nose mucus or earwax and couldn't find any. I assumed that if one can extract DNA from hair, which has few cells with non intact nucleus'  then the same could be done with earwax, which also has few cells or mucus? The simpler the method, the better, given I am an undergrad with low experience.

i dunno xD but how much in mass of "material" you have. You can purify  DNA from raw leaves from the plants for example, so I guess if you are able to homogeneize your sample and provided you have 1)the equipment and reagents necesary (isopropanol, ethanol, sterile water a centrifuge) and 2) there is simply enought DNA material in the sample to begin with you could give it a shot. Anyway I completely dont know, i d try it if google hasnt said otherwise i guess.. anyway SE i summon you

@Katz            I could wager i could collect the samples from my own nose and ear. And i do have access to those materials. So are you stating that a tradition extraction method for something like spit or hair would be suitable?

why do you want to do this btw xD

Just curious if I can do it as a side project, since I will have access to human primers for PCR and possibly have leftovers.

try oral mucosa as DNA source then, i am totally convinced that you should get routine protocols online to do that with PCR as a goal.

@Katz           I have a protocol for spit, id rather get something specifically for "boogers" and "earwax".

why? the DNA is the same so it wont matter to do PCR. anyway if it is a must, i guess as i said you can try with the classical DNa estraction method and see

Let us continue this discussion in chat.

im sorry just saw it, anyway im kinda busy and cant really. but anyway i dont have anymore to say i guess, just try it if you feel so and see what happens. good luck!


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Recommendation for book about soil and their food webs
Are there any de facto books for studying soil biology; specifically with details in the context of food webs? I am trying to teach myself about the subject and would like a good introductory book, although I will take any recommendations. Thanks

A very good resource can be found here:
http://esdac.jrc.ec.europa.eu/content/global-soil-biodiversity-atlas
If you focus on soil analysis this resource could be helpful:
http://www.geokniga.org/bookfiles/geokniga-handbook-soil-analysis.pdf
I could also recommend the book
http://www.springer.com/gp/book/9783642309410
with which I worked extensively. It covers the soil chemistry very well.

I really enjoyed reading "Essential Soil Science" by M.R Ashman and G.Puri.
https://g.co/kgs/SCjpSi
Seems to be easy to get online as a pdf as well.


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Resource for learning analysis of sequence data via QIIME 2
I am trying to study/learn metagenomics through 16s rRNA microbial data and I want to teach myself/review core biology concepts while also learning the QIIME 2 analysis pipeline, as the website suggests learning it instead of QIIME for beginners.
I found a great source : http://www.science.smith.edu/cmbs/wp-content/uploads/sites/36/2015/09/Tutorial-from-sample-to-analyzed-data-using-Qiime-for-analysis.pdf
but was hoping for something with an analysis I could actually work through on my own, as this one involves the use of a cluster, where as I only have access to a laptop of moderate power and also one that involves QIIME 2.
Also something free and maybe as hand-holding as possible would be ideal too.
As for the platform I am learning on, it is a virtual box instance of Ubuntu.

The QIIME 2 tutorials are the place to get started - see here.

So do you think those tutorials could take someone from layman to decent? I read on your profile that you teach bioinformatics so I am willing to take any other advice too. Thanks

They will teach you QIIME 2 without assuming much background knowledge. If you're new to the idea of studying microbiomes, you'll probably want some other resources too, possibly including Gut Check and An Introduction to Applied Bioinformatics. (Disclaimer: I'm involved in both of those projects, but all content is free.)


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Do Ants have a sense of Direction?
Do ants understand which way is up or down?
Could they differentiate between uphill and downhill?

Actually No.
Amazingly there is this paper published on the motions on Ants which says:

The isotropic distribution of average speed appears as a surprising
  result since it would be expected, for instance, that ants progressing
  uphill should be slower than when moving downhill. For instance, Seidl
  et al. found lower speeds on steeper inclines in desert ants moving
  uphill, but indicate that desert ants progressing downhill displayed
  high velocities [42]. This is in contrast with our finding with Lasius
  niger in the present set-up where the velocity showed no dependency to
  the walking direction, even for the steepest inclination. However,
  Wohlgemuth et al. report, also in the desert ant, that speed was
  reduced in both their uphill and downhill channels (+540 ) compared to
  their flat channel, thereby excluding metabolic cost as a reliable
  means to gauge walked distance on various inclines [28]. In an attempt
  to determine the effects of inclination on the gross metabolic cost of
  locomotion in leaf-cutter ants, Holt & Askew report that ants
  travelled the fastest on a horizontal plane, and indeed moderated
  their speed with the inclination, both on the incline and the decline.
  They suggest that ants adapt their behavior so as to keep their
  metabolic rate constant despite changing mechanical demands.

Source: How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines


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What is this Tree?
What is this plant?
Location: Bangalore, India

It looks very very suggestive for Artocarpus altilis or Breadfruit tree.
Another variants -  Artocarpus camansi.

How on earth do you manage to do this.... +1 :)

@AliceD Thanks, this tree has very special influence in design history, so the task was easily solvable. Learn more about it http://www.ctahr.hawaii.edu/oc/freepubs/pdf/breadfruit.pdf


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Are genes on the 5' to 3' strand only?
I confused myself during studying, and wanted to confirm something. Since transcription via RNA polymerases only takes place in the 5'to 3' direction, that would mean that that 5' to 3' strand is the only one that contains the information to be translated later into a protein or mRNA or w/e.
So then the 3' to 5' strand would NOT contain any genes, but just the base pair complement to them? Or am I thinking of the concept of a gene wrong?

There is nothing called the 3' to 5' strand. Both strands are have the same polarity but the DNA helix is anti-parallel. Both the strands contain approximately equal number of genes. Sometimes the transcription from both the strands can overlap, leading to production of antisense-transcripts.
So RNA polymerase will read the other strand from its 3' to 5'.

Both strands have a 5' and 3' end. Some genes will be on one strand and some on the other. The coding sequence will always be 5' to 3', but RNA polymerase reads the template 3' to 5' to polymerize mRNA.

So then since RNA poly reads 3' to 5', both strands can be parent strands depending on whenever RNA poly stops?

depends on the gene, the location of polII interacting elements and the location of specific transcription terminator sequences. There is usually just one parent strand per gene, but bidirectional transcription is known of http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2576438/


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Binocular microscope use, diaphragm?
I am try to review my scope work, since my proffesor asked me to calibrate all the scopes for an intro class in biology, and it has been awhile since I used one. I googled "Binocular microscope use" and saw a powerpoint as my first link.
On page 21 it stated:

The diaphragm should be opened just enough to allow the objective lens
  to collect all of the light that comes through the sample. Opening the
  diaphragm too wide, allows some of the light to escape collection by
  the objective lens. Closing the diaphragm too much, causes aberrations
  of the image.

But if the diaphragm controls the amount of light passed through, why is "light escaping" a bad thing? Why cant I keep the light as wide as possible?
As an aside, if anyone has any suggestions for review on binoc. compound microscope use, I would appreciate it.

The escaping light causes unnecessary illumination, thus reducing the contrast.
This webpage has a couple of photos that demonstrate different microscope setups.


text:
Molecular genetics textbook (free?) suggestion for first time
I have never taken a molecular genetics course but want to prime myself for graduate school in the future. Does anyone have any suggestions or advice? A professor recommends "the molecular biology of the gene - latest edition" but I dont have too much money to spend on a text and simply prefer free/digital formats. ( less to carry)

Molecular Biology of the Gene is an excellent text that your university library may have.

Buy textbooks. Go without a meal or three if necessary, but buy books!

I can’t comment otherwise this would be a comment, not an answer, sorry...
If you can’t lay your hands on a cheap (legal) text book that is of quality and in digital format then  maybe check out course material from MIT open courseware or something similar. As a further alternative, you should be able to find decent pop science books which are applicable and may be more useful than you think. The Epigenetics Revolution, for example, provided me with a really solid grounding when first trying get to grips with the subject.


text:
If an organism is supported only by cartilage, does it have an endoskeleton?
Lamprey and sharks lack bones, but does this mean they are not classified as having an endoskelton? Does an organism need bone to be considered as having an endoskeleton?

From wikipedia

An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue.

Cartilage is a mineralized tissue so it counts as a skeleton from this definition. A bit further in the wikipedia article it says

The vertebrate endoskeleton is basically made up of two types of tissues (bone and cartilage)


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Effect of mutation on phenotype
Is there a type of mutation that changes the phenotype of an organism, but not the protein sequence?

Yes. It is actually the case of most mutations that affect the phenotype!
Only 1.5% of the human genome codes for proteins. About 5-10% of the human genome are regulatory sequences which do not produce any protein but greatly impact the phenotype by regulating the expression of coding sequences. A mutation in a regulatory sequence does not directly impact the protein sequence but can have drastic impact on the phenotype (and fitness).
There are a lot of such mutations that have been identified. Here are a few quick examples

Variation in Vertebrate Cis-Regulatory Elements in Evolution and Disease
A cis-Regulatory Mutation of PDSS2 Causes Silky-Feather in Chickens
A regulatory mutation in IGF2 causes a major QTL effect on muscle growth in the pig
Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element [..]

Do you have a reference for the statement that most phenotypic changes are caused by mutations in regulatory sequences? And what is the definition of 'regulatory sequence' in the context of the 5-10% number?

@Remi - Nice answer.

@AlanBoyd: Read the cired papers. For silky feathers, "The causative mutation is located 103 base pairs upstream of the coding sequence of prenyl (decaprenyl) diphosphate synthase, subunit 2" which is a regulatory protein.

@anongoodnurse I wasn't really asking about specific examples - obviously these exist - I was asking for a supporting reference for the 'most mutations' statement.

@AlanBoyd - Ah, sorry.


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The colors blue and golden (yellow-orange) and the human eye / brain
Many years ago I read a review in an article about why we love for example Lapis Lazuli so much. The article stated that there are two specific colors, yellow as golden (when it glows or shines) and a very certain type of blue (the one of Lapis Lazuli) or also a shiny dark blue. I think we are not talking about the way those are absorbed in the eye but rather which color has the biggest impact on our eyes. Like often we say red is a warning color and we see red as most 'aggresive' color this article stated that in fact this type of blue and gold is the one that causes the strongest respond in the human brain. They also added a chart back then where you could see this 'response' for each wavelenght.
I was unabled however to find anything related. I don't think it has to do with the absorption peaks of the human eye, the graph looked a bit different. Has anyone heard about this before?


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Assay for Glycosyltransferase
I want to do an assay to see, if an ordered enzyme is active or not. It's a glucosyltransferase from S. mutans which hydrolyses sucrose into fructose and glucose. It then connects the glucose-monomers to dextran. Our idea is to detect the free fructose. There are many tests for this, for example the Fehling-Test or the Tollen-Test. The trouble is, that they have to be heated on a waterbath - I think that's very suitable for microwell-plates. Maybe someone here has a better idea how to measure the enzyme's activity?

If you've access to a PCR machine or a heating plate with a microplate with a heating block you can use that

There are indirect enzymatic assays to detect fructose based on NADH production by glycolytic enzymes.

Yes, true, but they are very expensive (about 400 Euro).
Thanks for the answers, but we now sticked in to a new method with 3,5-dinitrosalicylic acid (photometrically), which also detects free fructose.

What about this kit? http://www.sigmaaldrich.com/catalog/product/sigma/fa20


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DNA Dead skin cells
If the stratum corneum is anucleated, dead cells - how is it that we are able to get DNA from buccal cheek swabs? Are we grabbing more than just the stratum corneum with the swab (eg. the underlying cells that are nucleated)?

I'm curious: does the inside of your cheek feel anything like the palm of your hand?

Thanks! I just read that the inner cheek is one of the places in the mouth with nonkeratinized squamous epithelium. So the cells we collect with buccal swabs are not of the dry cornified type and retain their nuclei. And the stratum corneum and granulosum are absent from this lining mucosa.

Because our buccal cavity is not covered by skin but by oral mucosa (nucleated epithelial cells).

Why the down votes?


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Are these birds in video real? What are they called?
I recently came acroos this video   :  https://m.facebook.com/story.php?story_fbid=1053324651468913&id=492140647587319
I want to know whether these birds are real or edited? If they're real,  what are their names?

The problem here is that your question depends on a video on another site and so is not a self-contained question here. Unless you can at least present some screen captures to illustrate the problem, it is likely to be closed.

Have been to many stackexchange sites,  have seen many such questions (& answers,  too), so I thought it was okay...  Moreover, taking ss would probably be illegal....!

I don't care who else breaks the rules. I am only concerned with applying them, and educating others to apply them, to questions I encounter as a reviewer on this site. There are many more violations than there are reviewers to deal with them. If you can't post a question in a way you consider legal don't post it at all. I vote to close this question as unclear.

@David Actually, I would like to keep this question open.  It could have been better, but I think the answerer gave us sufficient context  so it will continue to be useful for people.

@tbek — OK. I'll reverse my vote.

Somehow I found my way back to this question and would like to apologize for not asking the question in best possible way. However I'd like to note that I didn't even know, at that time, that I can find those birds over their (or the fact that such beautiful creatures do exist, and hence my question) and my question was motivated by the opportunity to search about them if at all they were real. I'd like to thank the user24284 for showing me "where to search" also.


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Why aren't human babies considered larvae?
I've seen people who are anti-baby describe babies, or children in general, as human larvae. This is generally done in order to make them seem weird. While I feel like this statement is wrong, I can't quite put my finger on exactly why.
Many definitions of "larva" specify that they must metamorphosize, or go through significant morphological changes on the path to adulthood. However, tadpoles gradually change form, rather than metamorphosizing, and hemimetabolic insects have larval instars that aren't substantially different from adults, aside from being sexually immature and smaller. "Sexually immature and smaller", of course, also describes babies fairly well.
Unfortunately, I'm no biologist and my knowledge of what defines animal young as larval vs. non-larval is rudimentary, at best, so I'm not sure if there's a more precise definition of "larva" than the one I found on wikipedia, which would disqualify human babies. What traits differentiate larva from non-larva, and which of those traits to babies lack?

I'm voting to close this question as off-topic because it’s a not about biology but semantics.

For animals with a clear larval stage, the presence of such a stage indicates that there is a metamorphosis, a change in body morphology at some point in development.
Metamorphosis does not necessarily refer to an 'instant' transformation or one that requires a pupation step or something similar; gradual change can still be metamorphosis, as long as there is a clear 'before' and 'after.'
Human infants, on the other hand, don't go through much of a metamorphosis: sure, they grow quite a bit, but their general body plan does not change. Contrast this with insects, or your tadpole example, and it is clear there are major body plan changes from larvae to adult stages.
The Wikipedia page on larvae describes the characteristics of larvae fairly clearly. Like most traits in biology that vary across taxa, you are likely to find some intermediate creatures where the presence of a larval stage is somewhat controversial or depends on opinion. There could be a difference of opinion on how much of a change is sufficient to describe a juvenile form as a larvae. Humans don't have a postnatal stage that approaches that potential boundary.
The part in your question about people who are "anti-baby" sounds a bit judgmental, but I think what you are describing is just a phrasing meant to be somewhat humorous and to evoke images of "gross" larvae; I wouldn't take that for any biological meaning and I wouldn't focus your time on proving it "wrong" - the actual difference of opinion you have is something entirely different.

Children certainly are not human larvae biologically, for the reasons explained in the accepted answer.
However, calling children larvae is a metaphor that refers to child's mental and social development rather than morphological. Stepping back and looking at a kid as human larva can give adults important insight:

A larva has entirely different needs and capabilities than imago. Adults sometimes forget that.
Important milestones of development (walking, talking, social training, adolescence) resemble instars: behavior and needs of a kid at given milestone have little in common with needs at previous stage.
The purpose of a larva is to molt into adult form. Which is something that many parents tend to forget: that the only purpose of their kid is to grow into a functioning adult eventually.
Actions of the larva make no sense for the imago, and imago can't be held responsible for it's previous instar actions. That's somehow a trope for family embarrassing teens/young adults with things they've done as kids. Larva analogy helps to deal with such situations and memories.

This analogy is anti-baby only used in context against babies. In some parenting books, this analogy is used to help parents understand their children better. The only inherently bad thing about it I can think of is exploiting some people's aversion to insects in general and larvae in particular.


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What is the striking speed of a Green Anaconda?
How fast does a green anaconda strike? The striking speeds of other snakes is readily accessible, but not that I can find for the anaconda.
If you have information for the size and weight of the anaconda, please include this with your answer. Any additional information about their striking is also welcome.

A herpetologist friend of mine recounted an experience of wading through a stream, and an anaconda reared up and struck him in the chest, and then pulled back. The strike ripped the man's T-shirt completely off. I can't answer your question, but remember that the strike was very fast, and was quite a shock to the man in the stream (although he was unhurt).

@KarlKjer Thank you for sharing! If I may ask, did the man comment that it felt like being punched?

Sorry, it was years ago. I vaguely remember that it did feel like being punched, but memories so old are likely unreliable.

Thanks Karl. I'm also investigating the strength of a snake strike, separately.


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Why does walking mitigate the urge to urinate?
When feeling a strong urge to urinate humans tend to walk around when e.g. waiting for the current bathroom occupant to get out. Why is that?