text:
What is this animal that hides in dustlike structure?
I'd like help identifying the species of animal in these two photos. There's some dust(or dust-like substance) with something alive inside of it (possibly a larva or I don't really know what to call it). This appeared in a couple of hours in the wall. Please, try to even just guess what this could be (I can't think of anything!). Very odd...
I don't even know what tags I hsould use for this!
Thanks in advance

new photo

How big is it? Where do you live? It's very hard to see any animal in the photos, but for example Case Bearing Moth larvae use fibers to make the "case" that it lives in. Or maybe a carpet beetle larva that happened to hide in this dust.

it's a bedroom. there's a dust around in a room(I cleaned a lot), but when I just came there's was a very big humidity in the air(you know, the smell of it...). It's one of my relatives home and I'm very disturb about it.

I think it might be a moth larva. And I really don't think one larva is reason to be worried! Just remove it and keep an eye out for more of them, in dust or perhaps wool materials.

I've been here for three days now, and noticed this yesterday... I removed three of them(yesterday) and today more two. while I was gone(for about 2-3 hours outside to travel in the city) this one appear... that's why I'm worried :/

Sorry to hear that (even if it's still not an outright infestation). I'm no expert, but I would recommend more vacuming, removing of materials that they like, and if they keep coming, googling for clothes moth pest control.

Where in the world is this, what's the nearest City?

This might indeed be a moth larvae. If you already found six, there might be more. Moth larvae generally eat something organic like plants, cotton or wool. Search for this source, it might be a plant, carpet, curtain, cloths, etc.

Related: https://biology.stackexchange.com/q/28479/16866

There's a lot of animals that do that: https://fr.m.wikipedia.org/wiki/Fichier:Reduvius_personatus,_Masked_Hunter_Bug_nymph_camouflaged_with_sand_grains.JPG

This is likely a case-bearing clothes moth (Tinea pellionella).
Though more information and a better image would aid in confirming that to be the case.
Here are some pictures:


text:
Ear ossicles a part of Skull?
Is there anything special about not considering ear ossicles as a part of skull?
I could not understand the reasoning behind such  classification.

The justification is simple.
The bones of the ear [ear ossicles] do not articulate with any other bone of the skull hence it is not considered as a part of the skull, similar is the case with the hyoid which is attached to the tongue.These bones have been placed under the group of associated bones.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Why does our face get red during anger?
My attempt: This site says that it is due to flight or fight mechanism, which results in more amount of blood being passed to face causing red face.
But isn't it wasteful for our body to send more blood to face than to our muscles for efficient action?
Also an answer to this question says quite opposite.
So, I think that first site maybe wrong.
So, what exactly is the reason for red face during rage(anger)?

Evidence for my claim:

Several physiological studies have demonstrated that human facial color also varies with emotional states. The face often flushes during anger, or pleasure, and sometimes goes pale when experiencing fear or fear mixed with anger.

Source:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5259783/

But does it get red? Do you have any reason to think this is not just a comic representation that does not match reality? You pointed to a post suggesting that our face gets pale when under stress, so it really feels like stating that our face turns red when angry is not evidence based.

Come on, Does this fact even need a proof? Have you ever seen an angry person?

I sure have already seen an angry person but I would not be able to tell whether their face turned red or not. We will see if other usage are happy about considering "faces turning red when angry" as common knowledge or whether they doubt about this claim. I might be the only one unsure of this to being true. If I may, a correct terminology would imply saying "Does this claim need evidence" rather than "Does this fact need proof".

Thanks for correcting my English. Please see my edited question.

Why voted to close?

I did when I I commented. You made an edit since. However, it seems to me that the edit rather argue that our face goes pale when experiencing fear or fear mixed with anger, which is right the opposite opposite from you claim and the site that sustain your claim. I think the first question is really "Does it turn red or pale?". The video in the first link explains why it would turn red while the article you link explains why it turns pale.

Let us continue this discussion in chat.

@JM97: I have seen many angry people, enough to know that there are individual differences in the way anger is expressed, and also different types of anger.  The red face is a stereotype, but by no means universal.

But do you agree that it happens in some? If yes then there must be a reason for that too. So what could be the reason. And why it's an opinion based question? Is the physiological reason behind it is opinion based??

The comments and answer so forth are mainly related to the visibility and possible social and evolutionary explanation of the 'red face'.
While not discussing the social or evolutionary factors, I can give an overview of the biochemistry involved.
Anger and associated feelings such as stress are part of the 'fight or flight' response. This response is regulated mainly by the release of epinephrine and norepinephrine (the same as adrenaline and noradrenaline) into the blood stream by the adrenal glands, and from neurons into the synapses.
Wiki:Fight or Flight response
(Hence, the signal is send out both in the whole organism, and locally between neurons).
These hormones/neurotransmitters have a number of physiological effects:

They trigger a combination of vasoconstriction and vasodillation  in different parts of the body, meaning that the blood vessels constricted and widened, respectively, in different tissues.
This allows for a more effective transfer of nutrients to the muscles and brain. Wiki: Epinephrine
They trigger the increase of blood sugar by breakdown of glycogen deposits. Again, the body is in a situation where it needs to use the available energy ressources.
The heart rate is increased. Again, this allows for more effective transportation.

As listed above, the hormones related to anger both trigger the constriction and dilation of blood vessels in different tissues. Thus, the routing of the blood through the system also changes.
However, the routing of the blood seems to differ, depending on the exact feeling, where blood sometimes are routed to the surfaces areas of the skin, and sometimes away from them (by means of vasoconsttriction and vasodillstion, respectively).
Intuitively, this is can be a way of controlling the body temperature, as the body can expose the warm blood to the surroundings to a lesser or greater extent.
I don't think it is entirely understood, what determines this, but a guess could be that in situations of anger, the body has to be able to effectively use the muscles and fight, and thus also needs to be cooled, in order for the systems to work properly.
In situations of fear you might to hide instead for a long time and preserve the body heat and energy (just speculations).
Besides, it also could have a social impact.
But when blood is transferred to the facial areas, including the brain which needs energy to think quickly, and the skin surface for cooling down, it can have an affect on the perceived color of the face.
As noted by others, the degree of visibility is highly personal, as it depends on several factors such as the degree of hormone release, hormone sensitivity, anatomical features of the face such as placement of blood vessels, skin color and so forth.

Welcome to Biology.SE and thank you for your answer. Could please give some references (preferably peer-reviewed articles or e.g. Wikipedia for common knowledge). Also consider taking the tour and look at what is considered a good answer on this site for further information. Thanks!

I don't think the answer to your question is known per se, and as some comments pointed out the claim "our face gets red during anger" itself needs examining.
I will provide one element to think on however, which is that with emotional responses in general there might not always be a simple physiological reason for all the physical manifestations of the emotion, and if there is it might not be the whole story. There can very plausibly be social reasons why our emotions are visible and hard to control. It's useful for communication, letting other people know how we feel; it could also be useful to get people to do what we want (if someone is visibly angry in a way they clearly can't control then there might be other things they can't control and any threat they make may be more credible because of that; someone who's visibly upset demonstrates that they care about an issue more effectively than just saying they care does).
In other words, it is quite plausible that there were adaptive reasons for us to develop visible emotions, and from there any physical manifestation of those emotions (such as getting red in the face) might well exist mainly because it makes the emotion visible, and not because that particular response has a specific use beyond that.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What would happen if some neurons are unmyelinated?
I know that cold receptors have myelinated axons and heat receptors don't.
From a physiological perspective, what could be the consequences if cold receptors were unmyelinated? Would that pose some detrimental effect?

i am not sure but human sensitivity to cold could become more than sensitivity to heat because the speed of impulse conduction would be higher in a myelinated fibre than an unmyelinated fibre...so coldness must be physiologically some how more detrimental than hotness specially if u consider enzyme activity and thermoregulation...

The nociceptors (pain including noxious heat and cold) are unmyelinated (and thus pain sensation is delayed). Usual sensory neurons are myelinated.

ASFAIK there is a fast component of pain which is myelinated, and this fast component include thermal and mechanical components.

Is your main question about cold receptors or about neurons in general (as your title suggests)? And exactly what do you mean with a detrimental effect?

From a physiological perspective, what could be the consequences if cold receptors were unmyelinated?

Per the resistor-capacitor model of a neuron, one would expect signals conducted through myelinated axons to be faster, more sharply localized in time (spikes don't broaden out as they propagate down the axon), and less costly of energy, vs in unmyelinated axons.
I wouldn't read too much into significance as there's all kinds of ways to accomplish the same effect at any level, e.g. faster conduction is also accomplished through larger axon diameter, and better temporal localization is also accomplished through signal coding, and energy consumption is also modulated by tweaking membrane composition of ion channels etc.

Would that pose some detrimental effect?

Generally, if it's normal for axons to be unmyelinated then one would expect things to be running normally. Demyelination of normally myelinated axons pretty much always leads to loss of function in sensation or motor control.
The question to ask here is rather "Would myelination of normally unmyelinated afferents pose some detrimental effect?" I'm actually not aware of any disorders in which there is "extra myelination" -- Even the dysmyelination disorders are all loss of function in the proteins, not extra insulating myelin or myelination in the wrong place. That doesn't mean there aren't overmyelination disorders, but does suggest that our nervous systems are less sensitive to overmyelination if it is a thing that happens.
One would expect conduction velocity and energy consumption to decrease, okay. Probably not an issue unless temporal synchronization in that signal is important; even then "plasticity" usually irons out these problems.
If the normally unmyelinated afferent axon normally has synapses homogeneously distributed along its shaft, then abnormal myelination could cause abnormal development of these synapses. As contact area would only be available between myelin "nodes," synapses would be crowded into smaller area. Also depending on how development works in the systems you're considering, overmyelination might affect the spatial pattern of secreted growth factor concentration which could affect synaptic development along the axon shaft. But this is all completely hypothetical.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Spontaneous generation of fruit flies
I live in the South of England. It is currently winter.
Whenever I buy bananas, even one, if I leave the discarded banana peel in my kitchen, within hours or even minutes, there is a cloud of little flies to be seen in the vicinity.
Given that this doesn't happen with other fruit such as apples, I hypothesise that these flies spontaneously generate in the presence of opened bananas and/or their peel.
Notes
Bananas are not native to the British Isles and are imported from hot countries.
I can go months or even years without purchasing a banana and yet, when I do, these flies appear almost immediately. They also disappear almost immediately when I dispose of the fruit and its peel.
The flies do not appear until I unpeel the banana.
Question
How can I disprove my hypothesis of spontaneous generation?
Note: A secondary hypothesis is that fruit fly eggs are distributed all around the world (including in my kitchen) and simply waiting for a banana to appear. This seems less likely but more difficult to disprove. If this is so, how do the flies have time to mate and lay the next generation of eggs in my kitchen when the banana detritus is disposed of almost immediately.

Francesco Redi performed this experiment 350 years ago: https://courses.lumenlearning.com/microbiology/chapter/spontaneous-generation .  Further work by Louis Pasteur and John Tyndall ~150 years ago definitively convinced the science community that spontaneous generation does not occur -- a belief which is in no way controversial to this day.

@theforestecologist: But that rather begs the question: where DO the fruit flies come from?

Regarding spontaneous generation:
Francesco Redi performed an experiment 350 years ago disproving spontaneous generation of insects (see here).

 Source: Lumen Learning
Further work by Louis Pasteur and John Tyndall ~150 years ago definitively convinced the science community that spontaneous generation does not occur -- a belief which is in no way controversial to this day.
Regarding fruit flies:
Fruit flies lay their eggs in fruit. According Orkin, the eggs will hatch into larvae in ~30 hours when in an optimal temperature (75-80 oF).
Produce is typically refrigerated during shipment and storage to prolong shelf-life. This means that the hatching process is halted until the fruit nears your home (or on the grocer's shelf if they are not managing their temperatures or unboxing procedures effectively). Assuming your grocer is taking good care of their fruit (i.e., keeping it cool), then you are likely only starting (or restarting) the egg-hatching timeline after you bring the fruit home. Result: you find fruit flies in your home that you didn't see in the store.

Ripening bananas, by the way, produce their own heat. So even if ambient temperatures are cooler than optimal for fruit flies, the heat from the ripening bananas might push the temp within optimal conditions. This is especially true if bananas are in any form of storage container (e.g., their shipping box). This is why a good grocer opens their banana boxes upon arrival -- it extends shelf-life and prolongs/prohibits fly development. (This also means that if the grocer doesn't unbox their bananas or leaves them in dense piles in poorly refrigerated display shelves, the 30-hour timer started before you brought them home).

So if Redi had performed his experiment with bananas instead of meat, he would have found that spontaneous generation occurred :-)

@jamesqf actually, if he'd just let it sit long enough, bananas would've grown out of the meat.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Are these bat social calls?
I'm currently researching bat social calls (not echolocation calls) and have been given a series of samples (in .wav format) and wanted to know if what I can hear is actually the social calls. Below is a Graph representation of the a sample from the data I have:

This looks fine to me. From this, I can clearly tell where the social calls are. If I play at the specific peaks, then it sounds like a bat "chirping." However, I've been told that social calls cannot be played back, and, therefore humans cannot hear them. I'm just trying to figure out what these noises, or, chirps might actually be.
Here is a link to the .wav file:
Thanks for your help :)

Come on, edit your question and ask it.

Ha ha! Yes it seems at first sight that such question would fit this website. So, as @Chris said, edit this question (including the title) and directly ask your question on bats and social calls.

@user1326876 Have you gotten any explanation other than "its impossible" why you cannot record the social calls?

@Chris - The social calls are recorded. I was told "it's impossible" to play the social calls back, since, they were recorded real-time and cannot be detected with just a standard media player.. But if this is the case, what am I hearing when playing these files back?

It could not fit in a comment..
You recorded bats. You are interested in social calls. Socials calls can be recorded by your microphone but they cannot be read by standard media player because...

the standard media player are limited to certain frequencies
your speakers cannot produce such high sounds
your ears are not able to hear many of the frequencies emitted
you formatted your records in a format that cannot hold very high frequency (for reason of optimizing data compression)

You might use some program like Adobe Audition in order to easily visualize the frequencies (vs time) of your record. (It might also help you finding all harmonics or performing Fourrier analysis)

This wiki article says :

Social Calls
This is a wide subject and there is still a lot to be discovered about bat social communication and how they use social calls in roosts and when flying. Generally a bat social call is not tonal, in other words it does not consist of a musical type note. Some bat detectors do not produce an accurate recording of a bat social call. Typically bat social calls use a lower frequency range than echolocation calls, and can thus be heard further away. Sometimes a bat will make a social call while echolocating which can cause confusion.
We can see and hear how the lower frequency social calls are heard at a greater distance than the higher echolocation calls as the bat approaches and departs. Zooming in on a spectrogram, social calls are atonal and repeated rapidly about five times in each call. The social calls are interleaved between the echolocation calls. They show a ragged frequency distribution around 20 kHz. Note the FD detector divides frequencies by 10.
The echolocation calls are single "hockey stick" calls at a higher repetition rate. At this scale the hockey stick shape is not very clear, but the end frequency can be measured as 45.2 kHz. A doppler shift is recorded as the bat approaches. The frequency was measured as it passes

I believe the first one. But, if this is the case. In the sample I gave in my post. What is it exactly I'm hearing? I have performed the a FFT on the signal, but, it still does not give any indication to where the social calls actually are.

For example, could it be that the person who has recorded these bat samples has already made it possible to hear the calls?

You want to know when you hear socail calls. Well, if social calls of your bats are around 20 kHz (at what frequency do you expect to find these calls?), then you might find signals on the frequency spectrum around 20 kHz. If someone modified the records by shifting the frequencies, he would have probably notice it somewhere. That would be surprising. But the best is always to contact the dude who took these records

Okay, thanks! I'll take a look at the FFT and see if anything comes up at the specific frequency range. Is there a chart or something for different kinds of bats at what frequency they can be heard at?

I am affraid there not enough study to create such a chart (But I don't know much!). you may try this article though. If you know which species you're dealing with you may find some studies that compared individual-specific or group-specific social calls

Thanks, but, this does not answer my question. What exactly can I/you hear from the recording I posted? If they are not social calls, what are they?

Did you have a look on this two Wikipedia articles (I know, its not a scientific ressource but sometimes a good starting point): Bat species identification and Bat detector. They go into some of the details discussed here.

I know it does not answer. I don't quite know to what frequency these sounds we can hear correspond. But anyway, I would recommend to you to contact the guy who made the record he will probably manage to help you a lot.


text:
Identification by tail feather
I saw the remains of a bird today I did not recognize, and it was pretty mangled so it was hard to describe it. It was about the size of a robin. However, it had a dark brown mottled body like nothing I have ever seen. I have included below a tail feather from the bird which is 5 inches long. I am sure it is not a thrush or a woodcock or a kestrel. So what was it?
Location is Great Bay, Portsmouth, New Hampshire, United States.

Alas, I can't answer the question, but I can suggest you check at this link: https://www.fws.gov/lab/featheratlas/index.php

I believe this is a tail feather (or retrix) from an adult male eastern whip-poor-will (Antrostomus vociferus). See right image below (click to zoom):
.
 Source: USFWS Forensics Laboratory
Details:

The brown, mottled appearance and the size (~12 cm) match that of the OP's specimen.

A great resource for exploring bird feathers: https://www.fws.gov/lab/featheratlas/

The whip-poor-will's breeding grounds include the OP's location (i.e., New Hampshire), and according to All About Birds this species could still be present even late in the year ("they seem to leave between early September and late November.").

 Orange is breeding. Source: All About Birds.

The whip-poor-will is a medium sized bird and similar in size to an American robin.

Whip-poor-will: 22-26 cm ;  Robin: 20-28 cm

 Eastern whip-poor-will, (c) Paul Cools, source: inaturalist


text:
Help in identifying an insect
My cat has been messing with that insects. It looks quite unusual.
Anybody here can help me identify it, so I can make sure it's not dangerous?
Location: Israel

Please provide location information and any possible info about the insect (e.g., where you found it, approx size, observed behavior, etc.). The answer you accepted is wrong, but a correct ID is not possible without more info

Once again, this is a  longhorn beetle (Cerambycidae).
The overall appearance fits well with the subfamily Lamiinae (flat-faced longhorns). I would also guess it's in the Batocerini tribe. Though I don't think this is your species, per se, here is an image of a female Batocera rufomaculata with white stripe for comparison:

Once you provide more information about location I can give you a more precise answer.
Monochamus scutellatus is almost certainly incorrect. Notice the lighter coloration , wider body shape, and presence of a lateral white stripe along the side of the OP's insect vs that of M. scutellatus.

With a photo of this quality and zoom, it really looks creepy! :>

I think that your insect is a White-spotted sawyer. For more information check this: Monochamus scutellatus, commonly known as the white-spotted sawyer or spruce sawyer,is a common wood-boring beetle found throughout North America. Adults are large-bodied and black, with very long antennae; in males, they can be up to twice the body length, but in females they are only slightly longer than body length. Both sexes have a white spot on the base of the wings, and may have white spots covering the wings. Both males and females also have a spine on the side of the prothorax. Most research done on M. scutellatus focuses on their relationship with burned forests and the logging industry,with interest also being shown in their mating behaviours.

This is almost certainly incorrect. Notice the white stripe along the side of the OP's insect, which is absent in M. scutellatus. Also notice that the OP's insect is not black. Further, insect ID answers should always provide references (because of people's propensity to provide incorrect answers)


text:
For humans, why is red the color of distinction rather than green?
The human eye is most sensitive to the color green. However, for some reason red is often selected as the color of distinction or alert. For example, in Renaissance times, painters would outline their figures in a thin red line. In manuscripts, a "red letter" (or "rubric") was used to emphasize an initial capital. Today, we routinely use red for emergency lights or whenever we want to call attention to something. Considering that red is the color our eyes are least sensitive to -- and green the most --  it seems counter-intuitive that we would use red when we want to draw attention to something. Why is this?

I think strictly you're mixing two concepts of color.  We can talk about a frequency of pure light (or a single photon) in terms of a color under the purview of optics.  But optic colors are poor metrics of what we see; instead, we incorporate a theory covering multiple frequencies of light with various intensities (spectra), combined with how they affect our cone sensitivities across an average of humans, under the purview of colorimetry. That in mind, our eyes are most sensitive to optic green, but red lights/paint is colorimetric red.

you make a number of unsupported claims throughout your question. Please indicate some prior research to support these claims and to indicate your own effort to answer this question.

Related question: https://biology.stackexchange.com/questions/24481

Perhaps because (at least in Western Europe and eastern North America, where these conventions originated) most of the world is green for most of the year, while only occasional ripe fruits and flowers are red.  Thus red stands out against the green background, while green blends in.

The reason is more historical than biological.
Our own eyes are more sensitive to green light, and ambient light is mostly green (we are a diurnal being). If you start doing real botany, you will notice that you can distinguish a lot of species just from the shade of green (and for trees, this also from far away).
Red is a difficult colour to produce, and often not very stable over time, and in nature is not so frequent. But it was used because it was also not very common in constructed environments. For example, for the Romans it was a symbol of power (and richness) because it was very expensive to produce red dyes. So red is visible because of the contrast with other colours.
The most visible colour is yellow: the "red" cones are really centred on yellow, and the "green" cones are still very sensitive to yellow. A good yellow appears brighter than any other colours because it stimulates both  the medium-wavelength cones and the long-wavelength cones in the human eye. Now emergency services tend to use yellow.
Note: red is not so special (but having a third type of eye cone is very special). Blood is red, but one rarely sees it as red: it quickly turns dark. Fruit? I think blue, green, yellow, orangeish, and dark brown were more common than red (and I recognize a tree by its leaves, from far away, so I'll know what fruit there are).
Traffic light: lights were already very yellowish, and blue, purple, and violets are not that visible, so green, orange, yellow, red, and also white are the most logical colours. I think yellow and white were too similar (especially in cities), because they were the colour of illumination and headlights. Note: in maritime traffic, red, green, yellow, and white are used (not orange).

This answer needs citations. Please see our guide to writing good answers in the help section. Thanks!

@theforestecologist: Adding citations is complex: I like the area of colours, but it is not my field, so I know it mainly from secondary sources (and technical point of view, so just as a "user"). If you tell me what one or two important points which requires a reference, I can add, but I give hints to "students", I would really not do their homework. Also considering the most controversial parts of my answer (IMO) are outside biology.


text:
What is the actual chance of sibling incest child suffering from a genetic disorder?
This is not a question about the (a)morality of incest or current laws. However, there seems to be a widespread misconception about the impact of sibling incest on the genetic health of the eventual offspring.
What is the average chance that an offspring of a random sibling couple will suffer from a genetic disorder compared to an offspring of any random unrelated couple?

There is an average answer - I am specifically asking about random human couples.

Fair enough. I don't know that there is an answer, though. Different populations have different genomes and risks, and it depends on how closely related (e.g. small gene pool population) the parents are. You'd have to look at multiple studies, probably many of which have not been done. So, still, probably no reliable answer.

Usually when we talk about genetic disorder risks for closely related pairings, the concern is the high probability of homozygous recessive alleles.
Lazarin et al. 2013 screened ~23,000 individuals for 108 genetic diseases and found 24% were carriers of a known allele for some disease. Including carriers of multiple alleles, the total frequency comes to about 38% (this is a lower bound because only known alleles can be screened; there may be many other variants that are not known to science that cause the same symptoms).
That means about a 62% chance that one of an individual's parents carries one of these alleles (1-.62*.62 - note that this 62% has nothing to do with 1-.38, just a mathematical coinicidence with rounding).
If a parent is a carrier, each sibling would have a 50% chance of also becoming a carrier; the probability that both siblings are carriers would be 25%. The probability that an offspring from those siblings would be homozygous recessive would be another 25%. .62*.25*.25=3.9% (note that these are all lower bounds, the chances would be much higher if there were multiple recessive alleles present or if both parents were carriers for the same gene).
However, this is limited to Mendelian mutations just for this subset of known alleles. There are many many more conditions and disorders that have more complicated genetics that we may or may not understand, so that the original question becomes nearly unanswerable. In fact the paper I cited only paid attention to what were considered "major" disorders and even left out the Mendelian alleles known to cause more minor issues (including clotting disorders that can easily lead to death in the right circumstances). There are also many mutations that don't cause a clearly defined disorder but cause some other more limited issues that could predispose the offspring to other illnesses.
Lazarin et al. 2013 refers to estimates that each individual carries about 4-5 lethal recessive mutations. Given that siblings are very likely to be carriers of the same particular recessive mutations, this would significantly impact any offspring well beyond the estimates for the known disease alleles.
References
Lazarin, G. A., Haque, I. S., Nazareth, S., Iori, K., Patterson, A. S., Jacobson, J. L., ... & Srinivasan, B. S. (2012). An empirical estimate of carrier frequencies for 400+ causal Mendelian variants: results from an ethnically diverse clinical sample of 23,453 individuals. Genetics in Medicine, 15(3), 178-186.

Thanks for the answer. I was wondering if we could extrapolate from the many real world examples of offsprings of first cousins - there must be millions of children, right? And the probability of homozygous recessive alleles in first degree relatives should be exactly 4 times higher, right? Actually I found an article saying exactly that https://www.larasig.com/node/2020.

Nicely done. There were all Americans, I presume? Mendelian vs. non-Mendelian aside, there are subsets of populations in which I would expect much higher rates of lethal (recessive) genetic mutations, the most obvious being Ashkenazi Jews. All in all, I think this question is not answerable, because the studies just haven't been done.

@anongoodnurse Yes, Americans, including a slice of all ethnicities although some are under/overrepresented. Africans/African-Americans were underrepresented. Ashkenazi Jews are quite overrepresented, probably because the study is from people undergoing preventative screenings and that community is aware of the risks. I agree the question as asked isn't totally answerable, but I think it's reasonable to estimate. What I tried to address in my answer is that the issue isn't just the known alleles but all the de novo or unknown alleles.


text:
What is the name of this snake?
This baby snake just came inside my house in Sri Lanka, and I'm wondering whether it is venomous. Do you know this snake?

I am posting this from my phone so I am unable to format properly. And I have small children in my house, therefore I am worried about their safety.
Size: < 30 cm (I think it was a baby snake).
Location: Sri Lanka (in southern Asia)

We live in an urban area without any rivers near by.

Could it be the rat snake? http://bio.davidson.edu/herpcons/herps_of_NC/snakes/Elaobs/Ela_obs.html

no it's not a rat snake. At least not the black rat snake you linked to.  These are typically very black and live in the Eastern / Mid-Western portions of the United states

This is non venomous wolf snake.

I'm not an expert by any means, and anyone with proper training could probably provide a more informed opinion, but here's my thoughts. The patterning looks similar to Oligodon taeniolatus, an small, nonvenomous snake found throughout the region:

I'm not entirely sure about this identification, mostly because the pattern on the head looks a bit different. Sri Lanka has a large diversity of snakes and finding an definitive identification might be difficult without better images. There seems to be only a handful of snakes considered deadly, and this doesn't appear to be one of them. However, as I said, I'm not an expert, and even if it's not one of the 'deadly' ones, that doesn't mean it couldn't be dangerous to small children or pets. If you intend to capture and release the snake away from the house, I'd still recommend caution when handling it or contacting a professional.

The color seems similar but I don't think this is the snake, as the one in the picture doesn't have any patterns on it. I tried googling for golden/yellow snakes but couldn't come up with a closer match myself.

The one in the question clearly has patterns on it

The back dotted pattern looks similar, but I agree there doens't seem to be the same head design in the OP's picture. Possible juvenile or indication of sexual dimorphism in this species.

My answer's coming late but thought it's worth checking out the comment made by Anutapa bhattaharya that it was a wolf snake. I realise he only said it with no references or photos but still, since his name strongly suggests he's from Sri Lanka, I thought I'd see.
I believe he's correct and the snake in the photo is an Indian wolf snake (Lycodon aulicus), a common non-venomous snake that's encountered often enough in houses at night that it's earned the name 'house snake' in Sri Lanka.
I enhanced the first photo shown in Isuru's photo to better make out the markings and believe he's correct. Here are a few photos I found through Google of wolf snakes.

Source

Source

Source

+1 Seems like a pretty close match to me, also.

Just to add another option:
My guess (though no more confident than @p.s.w.g's answer)   is Balanophis ceylonensis (Sri Lankan Keelback) or related species.
The two features that stand out to me from your photo are

the dotted markings on the back of the snake, and
the dark line running behind the snake's eye.

You'll notice the keelback in this picture copied  from Fernandoa et al. (2015) has an almost identical skin tone and line running behind the eye.

However, this image does not show the dots.
Though a mature snake is very different colored, you'll notice from this picture that the mature keelback has a very similar spotting design as the snake you've photographed.

IF this is the case, and this is in fact your species, then there is at least one source (Fernandoa et al. 2015) that suggests that the snake is venomous.

This seems to be a good guess also. Here's another image of B. ceylonensis that looks similar the one in the question (here called a Sri Lankan Blossom Krait).

According to my mom (she is not a biologist) this is a rat snake (my question). https://biodiversityofsrilanka.blogspot.com/2013/09/garadiyarat-snake-ptyas-mucosa.html


text:
Identification of this species of Toad
I found a short video on the Internet of a toad and I wonder if anybody could identify it?
It was posted on a social-media/blogging website called 'Tumblr',

so I don't know much about it (e.g., where the video took place).

EDIT: The original link is no longer active. Here's an alternate link.

Useful for hearing the specimen's "squeak"/scream.

EDIT 2: Here's a gif of some frames from the video for permanence on this site:

P.s. I think it's a toad. Please, don't hesitate to correct me/edit my question, if i'm mistaken.

Do you know where the animal is from?

In all honesty, I'm not sure. Although i would Initially suspect it was filmed in North America. I presume, that the person in the video is keeping it as a pet too, so, it could be sourced far from there... Sorry, I'm not too helpful on this one :(

@p.s.w.g thanks for the update, but your link also doesn't seem to work :/

@theforestecologist whoops... copy/paste error. I've corrected the link (but will need to be reviewed)

This indeed looks like a species of "Pacman Frog."
Specifically, this specimen most resembles the terrestrial Ceratophrys cranwelli (Cranwell's horned frog or Chacoan horned frog).

 © 2014 James H. Harding
Facts:

8-13 cm long; can weigh up to 0.5 kg.
Origin: endemic to dry Gran Chaco region of Argentina, Bolivia, Paraguay and Brazil.
Cranwell's are very popular as pets.
Their common name comes from their large mouths. According to Wikipedia:

Like most members of the genus Ceratophrys, they are often considered Pacman frogs because of their resemblance to the popular video game character of the same name.

Like most reptiles/amphibians traded worldwide as pets, a fair amount of interbreeding between captive species (and even speciation as a result of captivity) result in various hybrids and color schemes.
I couldn't find any reputable sources describing the sound the frog makes in the video, but Valetti et al. (2013) studied their calls in the wild.
Closely related Ceratophrys ornata is both larger and typically much greener compared to C. cranwelli.

It looks to me like it's a Pacman frog or Ornate Horned frog, a common pet frog. The specific species, by googling pet websites, my guess is Ceratophrys Cranwelli (common name Brown Pacman frog).

They most certainly do look very similar! I'll look into it, now. Thank you for your contribution. +1. I'll mark your post as the answer, if so.

It is almost certainly a toad, not a frog as the name of the video suggests. It probably belongs to the familie Pseudepidalea, aka the green toads. The live in Europe, Asia and North-America. Wikipedia
I don't know the species, as I am.not familiar with the North-American species. This animal has relative large and few spots. That may help in identification, but may also be intra-species variation.
I can't see the video, only the opening still.

I apologise for the issues with the video, I'm not sure if I'm able to suggest any "work-around", for it neither. Your contribution to this question is much appreciated, however. Thank you for your time. +1


text:
Few deciduous trees in old forest
There is an old forest near me that has lain untouched for at least 150 years and possibly longer. The forest is on a big hill which is surrounded by a marsh.
The great majority of trees in the forest are gigantic hemlocks with aspens a distant second. The aspens are only found in the lower lying areas.
I am puzzled why there are so few deciduous trees in the forest. Deciduous trees are the most common around the town, and hemlocks are relatively rare outside the forest. The only deciduous trees in the forest are maples, and the few maples that are there tend to look sickly.
Why would there be so few deciduous trees? Do the hemlocks kill them off somehow, or would it be due to the soil?

Check out the radio lab podcast on underground network beneath of grow forests, perhaps it could provide you with some possible pointers to your question

Could you clarify what you mean by 'hemlock' in the question? Hemlocks are from the Apiaceae family and they are weedy.. Members of the Tsuga genus are also known as hemlocks but they are a kind of pine tree. A  sentence about the general location and climate may help as well.

150 years is nothing in the live of a forest, trees live for hunderds of years. If the hemlocks were planted 150 years ago it is no surprise that they are still there.

@Micael, Tsuga is really the only things that makes sense here, since poison hemlocks in apiaceae are herbaceous.

please provide the location of this forest

Interesting question, but we need a little more info. Location to start with. Some information on the approximate size and height of the hill. Any information you have of the soil (rocky or not?) and last: a picture would be great.


text:
Why is one phase of a plant dominant (Alternation of generation)?
In plants, there is the alternation of generation.
In nearly all land plants, one phase of the two possible phases is dominant--namely the sporophyte.
The "dominance" over the other phase can be seen in the following ways:

The gametophyte organism depends on its sporophyte progenitor, while the sporophyte organism is fine without the other.
The sporophytes are more structurally complex, larger and longer lived.
The sporophytes carry out more activities/functions and receives more subjective attention.

I want to know if there is an evolutionary reason why alternation of generation, one phase is dominant. Here are some guesses:

Zipf's law: as one of the two phases got more complex (start doing more complex jobs) It became more convenient and more likely for that phase to acquire other functions, causing the complexity of that phase to increase with a sort of positive-feed-back-loop, while it became more beneficial for the other phase to depend on the other more and more, to reduce its complexity.
Chromosomal difference: the sporophytes of plants are diploid while the gametophytes are haploid, perhaps one of the two configurations is more efficient?
The sporophyte generation "reproduce" asexually, perhaps this allows it to have a little "head-start" in accumulating non-sexually reproductive functions and became more complex as explained in 1.

Short answer:
Many of the evolutionary developments in plants developed in the sporophyte life stage. Because increased fitness of these increasingly sporophyte-"dominant" plants would result in a greater survival and reproductive success, these plants became more dominant than the more-limited gametophyte-dominant early plants.

In other words, natural selection of the fittest plants (which happen to have sporophyte traits increasingly adapated for living on land) likely led to the dominance in the sporophyte life stage.

Long Answer:
I would suspect this is due to the evolutionary advantages that are associated with the sporophyte life stage in land plants. Multiple advantages developed in the sporophyte stage of plants as they evolved from simple gametophyte-dominant bryophyte ancestors to the vast array of much more successful and dominant ferns, gymnosperms, and angiosperms.

 Shift from gametophyte-dominated life cycle (in bryophytes) to sporophyte-dominated life cycle. Source: Cengage Learning (2016)
Evolutionary developments that have occurred across almost 500 million years in land plants include the development of stomata, true leaves, pollen and seeds, and flowers and fruits. Each of these developments occurred in the sporophyte life stage.

Each of these evolutionary traits had significant effect on the success of the various plant types that possess them, as can be inferred from the increasing success and dominance of increasingly more evolved plant Divisions.
Each of these sporophyte-focused evolutionary traits increased the reproductive success of plants (therefore swaying increasing advantage toward plants possessing increasingly sporophyte-dominant life cycles) due to their ability to increase plant size, growth, and success living in arid (i.e., terrestrial) environments.

stomata allow for increased gas exchange with more limited water loss (note: these were necessary with the development of cuticles in sporophytes of early bryophytes as well)
vascular tissue2 allow plants to grow taller/bigger/more complex while still receiving water and nutrients from the soil
true leaves allow for greater energy capture and growth (and therefore increased competitive advantages)
pollen and seeds allow for greater dispersal and removes/limits the constraints of aridity on fertilization
flowers and fruits increase pollination and seed dispersal

Reducing the gametophyte stage to small cells within larger sporophyte plants allows this otherwise water-necessary process to occur in the dry conditions of living on land. As such, the pollen-bearing plants (i.e., gymnosperms and angiosperms) have been very successful in colonizing vast terrestrial ecosystems.
Another evolutionary advantage proposed, (e.g., see Bernstein et al. (1981)1 and Michod & Gayley (1992)3) is that the diploidy of the sporophyte stage allows masking of the expression of deleterious mutations through genetic complementation. From Wikipedia:

Thus if one of the parental genomes in the diploid cells contains mutations leading to defects in one or more gene products, these deficiencies could be compensated for by the other parental genome (which nevertheless may have its own defects in other genes). As the diploid phase was becoming predominant, the masking effect likely allowed genome size, and hence information content, to increase without the constraint of having to improve accuracy of replication. The opportunity to increase information content at low cost is advantageous because it permits new adaptations to be encoded.

However, this proposal has been more recently challenged by Szövényi *et al. (2013)4 because evidence suggests that selection isn't more effective in haploid vs. diploid lifecycle phases of mosses and angiosperms.

For further reading:

"Evolutionary history of plants" [Wikipedia]
"Evolution of Seed Plants" [Lumen Learning]
"Evolution of Seed Plants" [OpenStaxCollege]

 Citations
1  Bernstein, H; Byers, GS; Michod, RE (1981). Evolution of sexual reproduction: Importance of DNA repair, complementation, and variation. The American Naturalist. 117 (4):537–549. doi:10.1086/283734
2  Lucas, W.J., Groover, A., Lichtenberger, R., Furuta, K., Yadav, S.R., Helariutta, Y., He, X.Q., Fukuda, H., Kang, J., Brady, S.M. and Patrick, J.W., 2013. The plant vascular system: evolution, development and functions F. Journal of integrative plant biology, 55(4):294-388.
3  Michod, RE; Gayley, TW (1992). Masking of mutations and the evolution of sex. The American Naturalist. 139 (4):706–734. doi:10.1086/285354
4  Szövényi, Péter; Ricca, Mariana; Hock, Zsófia; Shaw, Jonathan A.; Shimizu, Kentaro K. & Wagner, Andreas (2013). Selection is no more efficient in haploid than in diploid life stages of an angiosperm and a moss. Molecular Biology and Evolution. 30 (8): 1929–39. doi:10.1093/molbev/mst095


text:
Species Identification - small insect
I found a few of these walking in the middle of the night (about 3 AM) on a wall in my room near the floor. They are at most a few millimetres long (no more than 2 I would say). I am living in Poland, in a block of flats.
EDIT:  Since I first wrote, I have seen few more - very small - less then 1 millimetre long. They seemed to be coming from behind the baseboard. This time I've seen them during daytime.

Looks kind of like a termite. It's generally helpful to include an approximate location in species ID questions to help us narrow down the possible species.

This would be helped with some better quality images - currently its hard to distinguish key features

@rg255 they are very small so I doubt I can get a better picture with my compact photo camera

I think @fileunderwater is definitely right, these are psocids (of the family Psocoptera, AKA booklice).
Specifically, the body shape looks very similar to that of Dorypteryx domestica or some closely related species.

See here for an additional photo.
According to this site, the species is present in many countries including Poland.
The source cited at this site (Kučerová 1998) mentions that this species can be brachypterous (i.e., having very reduced wings. I can't tell from the quality of the photo whether your specimens has tiny wings or not. Your top picture looks like it might.
Citations:
Kučerová, Z. (1998). Wing polymorphism in Dorypteryx domestica (Smithers) (Psocoptera: syllipsocidae). Insect Systematics & Evolution, 29(4): 451-57.

It could be booklice (Psocoptera), but the picture is a bit unclear. Booklice are harmless, but could indicate moist conditions and/or mold in the building (see first link for more on their biology). Termites are generally at least twice as large as booklice (>4mm), and the size you indice rather points to booklice.
Here is an example of what booklice look like:

(picture from Penn State University: Dept. of Entomology)

Thank you for your response. I was wondering if they are booklices myself, but on the photos their legs seems thicker near the body and I do not see that on the photos I've made. Since I first wrote, I have seen few more - very small - less then 1 millimeter long. They seemed to be coming from behind the baseboard. I also have added one more photo to my original post (I am not sure if that's helpful). Is there a way to verify if they are in fact booklices?

@man There are many species and the thickness of femur can probably differ between species (and is in either case difficult to evaluate in your pictures). Considering their shape, size, light colour (almost translucent) and long slender antenna they are probably booklice. Does the wall or wallpaper appear moist close to the baseboard?

I'm not convinced, the head, body and legs are all very different to the booklice in the image here

@rg255 This is a single example picture. There are e.g. >60 species in Sweden only (probably about the same in Poland)

wow, didn't realise there are so many species!

@fileunderwater The wall appears normal, but on the other side of the wall is a shower, there are probably water pipes inside the wall and I do not know how the situation look behind baseboard. Additional info: the room is a bedroom.

To be clear, the point of this answer is to indicate the taxonomic order to the OP, not a species identification. I though that would be useful, but apparently certain voters find it "not useful".

My initial guess was psocid, too, but the OP's picture really doesn't look like the typical psocid body shape I've come to expect. The OP's specimen does look A LOT like the one here, which is identified as a psocid but not from a trustworthy site.


text:
What is the difference between the mitotic spindle and microtubules?
In mitosis, I understand that the centromeres line up on the spindle. I also know that the centrioles form microtubles between the centromeres during mitosis in the metaphase.
But, are microtubles and spindles the same thing? Or do microtubles make up spindles?

Short answer
The spindle is made up of microtubules
Background
From Nature:

Spindle fibers form a protein structure that divides the genetic
  material in a cell. [...] At the beginning of nuclear division, two
  wheel-shaped protein structures called centrioles position themselves
  at opposite ends of the cell forming cell poles. Long protein fibers
  called microtubules extend from the centrioles in all possible
  directions, forming what is called a spindle. Some of the
  microtubules attach the poles to the chromosomes by connecting to
  protein complexes called kinetochores. Kinetochores are protein
  formations that develop on each chromosome around the centromere,
  which is a region located near the middle of a chromosome. Other
  microtubules bind to the chromosome arms or extend to the opposite end
  of the cell. During the cell division phase called metaphase, the
  microtubules pull the chromosomes back and forth until they align in a
  plane along the equator of the cell, which is called the equatorial
  plane.


text:
Why don't we speak of medial and lateral rotation of the forearm? And pronation and supination of the upper arm?
Why don't we speak of medial and lateral rotation of the forearm?
I notice we speak of forearm supination and forearm pronation, but why not medial and lateral rotation.
It seems to me that if we take the diagram of the human with palms forward, which I understand to be the neutral position one is meant to start from.. then forearm pronation looks to me like a medial movement. So why not medial rotation?
And similarly with upper arm.. why don't we speak of pronation and supination of the upper arm?  We speak of medial and lateral rotation of it..

Pronation and supination involve a change in relationship between the ulna and radius.

When you rotate your hand from palm ventrally (as in anatomical
  position) to palm facing dorsally you have moved your hand from a
  supinated position to a pronated one. This movement of supination to
  pronation occurs when the distal head of the radius rotates on the
  capitulum , the bone rotates along its long axis, and the proximal
  head of the radius flips over the ulna. (Duke Medicine)

and:

Pronation and supination are rotational motions that exist exclusively
  in the forearm. The mechanical bases for these movements are the
  existence of two forearm bones and the presence of two coupled
  trochoid joints—the proximal and distal radioulnar joints (PRUJ and
  DRUJ). (Clinical Gate)

Image source: Wikimedia, CC licence
During medial or lateral rotation of the upper arm (without additional rotation of the forearm), the humerus rotates, but the relation between the ulna and radius does not change, so there is no pronation/supination.
It is more practical to use supination/pronation for the forearm/hand, because you can have a forearm/hand in various positions where medial/lateral or internal/external does not make sense: for example, when you rotate your forearm/hand with your arm extended toward the side. Saying that, medial/lateral and internal/external rotation of the forearm is also commonly used (search: "medial rotation of the forearm"). So, you can use any of these terns according to what's more practical and less confusing in a given context.

ok, that answers for the terms supnation and pronation being forearm only. What about medial/internal and lateral/external rotation, why we don't say that of the forearm, or do we? maybe we do https://exrx.net/Articulations/Forearm

@barlop, I added that at the bottom of my answer. It's mainly to prevent confusion.

I think this line "It is more practical to use supination/pronation for the forearm/hand, because you can have a forearm/hand in various positions where medial/lateral or internal/external does not make sense: for example, when you rotate your forearm/hand with your arm extended in front of you or toward the side or placed on the table. "  <-- is incorrect, because the same applies to the upper arm , it can be out sideways, and they speak of medial and lateral there / internal and external rotation.

And your next thing "medial/lateral and internal/external rotation of the forearm is also commonly used "  is correct I think and proves that the previous thing was incorrect.

Also your last line "So, you can use any of these terns according to what's more practical and less confusing in a given context."  is I think unclear. The terms medial and lateral rotation can be applied to either. But as you showed, the terms pronation and supination only apply to the forearm

When you have your arm extended toward the side (lateral extension) and you supinate or pronate the forearm, you can't say if you medially or laterally rotated it. It is true that the same issue applies for medial/lateral rotation of the upper arm, but in this case is not really confusing. In summary: you can use all the mentioned terms for both the forearm and upper arm, except supination/pronation for the upper arm.

I think you've answered it I think I could possibly make it a bit clearer..  BTW you can say you medially or laterally rotate it because the terms apply because they're done with the human anatomy diagram of a person with arms down palms out, so you look at it from the perspective of arms down palms out when using those terms, even if the arm is out to the side.

Do you have any idea about question of mine on a similar subject? https://biology.stackexchange.com/questions/52346/confusion-regarding-degrees-of-flexion-and-a-goniometer

I'll look at it.

Supinus and pronus are latin words which mean lying face/body/palm downw and lying face/body/palm up. The hand clearly has a front and a back, and everyone knows where the back of the hand is compared to the front. It's a very clear medical word for describing the hand. Supinator and pronator muscles are also clear groups that action the hand to a prone/supine position.
If you ask which is the front and back of your forearm, not everyone will reply the same. The upper arm doesn't have a clear front and back, so it's not the best way to describe the forearm and the upper arm.


text:
Doubly-compound leaf examples?
I've got a project where we collect leaves, classify them, etc. There are some required classifications. One of the requirements is to get a doubly-compound leaf. What are some trees that are doubly-compound? Please help! I have Hickory, but that's just compound I think.
Edit: I did try googling, but it's hard for me to know what's available in my region.
From Comments: I live in Tennessee, U.S.

Where in the world are you? What kind of trees/plants do you have access to?

I live in Tennessee.

Hickories are not doubly compound (AKA bipinnate). They are just (once) compound leaves as you guessed.

For the future, you can try Weakley's flora app "FloraQuest". You can search for trees based on a dichotomous key and fortunately It'll automatically narrow your choices so you can only see local plants. Though this won't give you a list, it'll train you to use a valuable tool while searching for your own answers. (Note: it comes with a visual glossary of terms :D)

Albizia julibrissin (Persian silk tree) is doubly compound (AKA bipinnate) and has a conspicuous pink/white fluffy flower. This tree is an Asian native, but it's a commonly cultivated (and equally commonly escaped) plant in the U. S. You should be able to find it in numerous locations. Look in yards and along roads.

http://www.missouriplants.com/Pinkalt/Albizia_julibrissin_plant.jpg
For native species: Gleditsia triacanthos (honeylocust) is a fairly widespread (though uncommon) example of bipinnate leaves. Here is an image from Will Cook's wonderful website:

Many ferns have multiply-compound leaves
Take the one in this image, for instance:

That structure is one doubly-compound leaf.

Most plants of the caesalpinioideae subfamily of the leguminosae family are bipinnate, i.e., doubly compound. The best, and perhaps the most easily accesible one for you would have to be tamarind.


text:
What is the difference between Ostracodermi and Placodermi
I looked the word origin and found Placodermi is PLATE SKINNED while Ostracodermi is Shell Skinned.
Can someone please explain the difference between being Plate skinned and Shell skinned?

If in reference to the prehistoric groups of fish of the respective classifications, ostracoderms would have had a bony head much like a shell, and placoderms had articulated plates covering the head/thoracic area. The differences are relatively straightforward, see the wikipedia pages for each:
https://en.wikipedia.org/wiki/Ostracoderm
https://en.wikipedia.org/wiki/Placodermi


text:
Species Identification: large shiny black beetle, Detroit USA

What sort of beetle is this? I live in a suburb of Detroit and found a whole bunch of these living under my lawn when I was replacing a section of it. I'm assuming these are also the source of the grubs I found as well. Are these harmful?

You found a stag beetle (family Lucanidae).
Although the males are much more readily recognized with their large "stag antler" shaped mandibles, these species are often sexually dimorphic with females having much smaller mandibles (e.g., see here). However, in some species the males' mandibles are likewise diminished and not stag shaped.
According to the Wikipedia page:

Currently, the only means of identification of world species is the illustrated text by Mizunuma, T. and S. Nagai. 1994. The Lucanid Beetles of the World. Mushi-sha, Tokyo. 337 pp. based on the work Catalogue illustré des lucanides du globe in Encyclopédie Entomologique (series A 27: 1-223) by Robert Didier and Eugene Seguy.

So without this guide (and without known dimensions of your specimen), an exact identification will be very difficult.
However, your species looks very similar to a male specimen of Lucanus placidus.

Additional pictures (such as the one below) can be found here.

According to Wikipedia, L placidus is 22–35 mm long, has two or more teeth on its jaws and has dark femora. The species is sometimes found in soil and it does live in Michigan:

We can rule out Lucanus capreolus because the color is wrong:

[L. capreolus is] dark reddish brown in color with a smooth, shiny elytra; [their] femora are orange-brown.

It's a Lucanus. Don't know the concrete species.

It is not clear to me that the two insects are in fact from the same genus, since the Wikipedia stag beetle has much larger mandibles than the one pictured.

@MarchHo Mandible size varies between male and female, and between species in the genus, so it might be a type of lucanus. That said, this answer is probably more appropriate as a comment until something more definitive can be provided.

So, after all, it can really be a Lucanus, so why the downvote ? For a new user like me, it's very discouraging to get one.

A downvote just means the answer isn't useful. You haven't provided any evidence to support your answer at present. I'd suggest adding what key you used and ideally a pointer to some resources that would allow the OP to follow it up to species level (or if it's too difficult to go to species level, why it's too difficult). For what it's worth I think you're right about it being Lucanus (probably capreolus). Please check out the tour for advice on how to write a good answer. And welcome to Biology.SE!


text:
Identify this smooth-cocoon worm from Southern India
I couldn't identify which species these worms belong to. I believe they're insect larvae.
They measure approximately 5 to 10 mm in length, and are common in the southern states of India. They carry cocoons, open at both ends, which the worms can wriggle inside and alternate their direction of movement. These cocoons are perfectly smooth except for the openings.
Another post shows something similar, but the cocoon of that worm looks more woven, while this one doesn't.

It will probably be easier to identify the adult. Try to keep this in a jar or something and see what it becomes.

Probably a moth and here is an earlier similar question

i see these all the time and have tried finding information online a few times but never found an answer. this is the only photo i have seen that matches. i'm in eastern india. i really want to know the exact species!

I see them in Pakistan too. I personally call them "dust worm" Because they only exist in places where dust is available and there is no cleanliness for a long time.

This is definitely the larvae of one of a many number of case-bearing moth species. As noted in comments and elsewhere, these case-bearing moths show up fairly frequently on Bio.SE (e.g., see here, here, here, here and here for some examples).
Most of these moths are members of one of two families: Coleophoridae (the case bearing moths) or Tineidae (the fungus moths).
Some of these species even build cases that they carry around with them.
Your specific example is possibly Tinea pellionella (case-bearing clothes moth).
[
T. pellionella has a cosmopolitan distribution and occurs nearly worldwide (Cheema 1956). As the Wikipedia article summarizes, the larva feeds mainly on fibrous keratin (e.g., hair and feathers) as well as carpets, furs, upholstery, and woolen fabrics. The larvae remain inside a case it constructs from debris such as hairs and fibers (e.g., from clothing, upholstery, carpets, etc.).


text:
What insect is this? (Central Africa)
I live in Africa (DR Congo). Here we have these insects that look like ants. They appear between May and June.
These insects give severe damage if crushed on the skin. They contain something like acid that burns the skin. I saw many people wounded by them.
So I would like to know what these insects are, and whether they can cause death if swallowed? Can someone point me to where I could learn more about them?

PS: There are no forests near where I live.
Edit:

The insects appear at the end of the rain season (April, May)  and right before the dry season (May, June).
Attracted by (neon) light. I think they fly only once then drop their wings (not really sure).
Can be found in homes (houses).
Can burn skin like acid.
It measures approximately 5 - 8 millimeters (not sure. can't find one right now).
Crawls fast with its tail upwards (don't know how to describe else, see image).
Solitary animal.

It is a Rove beetle of the Genus Paederus.
Why Paederus sp.?

They are brightly colored  rove beetles, Coleopterans with short elytra.
Have metallic blue or green-coloured elytra.
Have bright orange or red on the pronotum and basal segments of the abdomen.

There are widely spread on the planet and I found two species of Paederus sp. that are found in East of Africa, together they are called Nairobi flies.

The medical condition it causes is called Paederus dermatitis.

According to Medical and Veterinary Entomology (2009) "At least 20 of the more than 600 species of Paederus beetles have been associated with Paederus dermatitis", even though Paederus beetles do not bite or sting.
This skin irritation results from contact with pederin, a vesicant toxin in the hemolymph of many but not all females in the genus Paederus.
The toxin is manufactured, not by the beetles themselves, but by endosymbiont bacteria, probably some species of Pseudomonas.
Three different genera of rove beetles, all members of the same subtribe Paederina, can cause paederus dermatitis: Paederus, Paederidus, and Megalopaederus.

Pederin

Pederin blocks mitosis at levels as low as 1 ng/ml, by inhibiting protein and DNA synthesis without affecting RNA synthesis, prevents cell division...

This makes it also a potent antitumour agent.

The manufacture of pederin is largely confined to adult female beetles—larvae and males only store pederin acquired maternally (i.e., through eggs) or by ingestion.
It is a contender of the title of most powerful animal toxin.
It is among the most potent animal products known, more so than Latrodectus venom, which is 15 times more potent than cobra venom.
Ingestion can cause severe internal damage and intravenous injection causes death ...

Further Reading:
1. Dermatitis Paederus: About 06 cases occurred in Bun
ia,
Democratic Republic of Congo
2. STUDIES ON THE MECHANISM OF ACTION OF PEDERINE, 1968
References:

 1. Paederus
2. Pederin
3. Paederus dermatitis
4. Encyclopedia of Entomology
5. The Role of Natural Products in Drug Discovery
6. ChEBI

Note: I found the picture in your question is the same as that of Wikipedia's picture of Paederus.

Oh thank you. It think this answers my question. The image was posted by a friend on Facebook so I thought would be better to ask here.

Very nice answer, Tyto alba


text:
Do ants have a "stay away" signal?
Last night I discovered many ants entering my house through a window with an imperfect seal. I placed a poison ant bait on the window sill and within seconds they were feasting on it. This morning I noticed there were still many ants near the bait, but they were all bypassing it as if they were somehow warned to stay away. Do they have such a signal? If so, how would they know the bait is a problem? If not, what could cause them to be so interested last night and not interested at all today? (I can see that there is still plenty of food inside.)
Update: after a little bit more research, I decided that ants do not have a "stay away" signal, and that the only explanation for ignoring the bait would be a stronger scent trail leading somewhere else. Last night when I opened the window I found the jackpot. There was some sort of sticky substance all over the bottom of the window, and hundreds of ants celebrating the find. My conclusion is this was much more attractive than the bait, even though it was merely an inch away from their path.

It is a long time since I set in a Computer Sci (AI) talk about this….  This explains it a bit.

Once ants have eaten they return to the nest.
On the way back to the nest they put down a scent.
This scent fades with time.
Most ants follow the scent.
(A few ants walk randomly to find new food, or a new faster way to the current food.)

So if the agents eating your poison bait do not make it back to the nest, there is no scent trail leading to the poison for more ants to follow.     But the ants that went round the bait to find other food, did make it back to the next, so setup a new sent trail.
If a poison kills the ants quickly, the customer is likely to see dead ants and therefore buys more of the poison.   However a poison that kills the ants slowly, so the ants don’t die until they get back to the next, is likely to get more of them, as there is now a strong sent tail to the poison.

interesting answer... makes sense - are there any available references that you could cite to back up the answer? It would improve its strength. Thanks for your efforts!

@VanceLAlbaugh, sorry nothing better then what anyone can find with google themselves.   But I have shown that a "keep away" signal is not needed to enable ant to "keep away" from something that kills them quickly.

I'm pretty sure the ant bait I used takes 1-2 days to kill the ant, so there should be enough time for them to get back to the nest. However, your implying that there was a stronger scent to a different food source turned out to be correct.

Yes, ants communicate with members of their colony by releasing specific chemicals and pheromones to indicate danger. The ants that entered your house and ate the poison must have released a "danger" chemical, thereby warning the rest of the colony. I suggest sticky traps for capturing the remaining ants.
Here is an interesting article on the matter.

Sorry, I'm not convinced. The article you referenced talks about a scent that only living ants have, which fades out about 40 minutes after death. Once the living scent is gone the ants know to remove them from the colony. It doesn't speak of a danger scent. I believe some ants do have a "danger" scent, however my understanding is that it's the opposite of "stay away". I believe it means "come here and fight, something is attacking us". So if the "danger scent" was released, I would expect more ants to appear (and perhaps frantically take the bait?), not avoid the bait altogether.


text:
Genotype result of double fertilization

So, clearly, the endosperm would be a fusion of the polar nuclei and one male gamete. Does this mean that each male gamete would have a T allele on it?
I can't seem to figure out a way to predict the allele distribution between the 2 polar nuclei since the flower has a Tt genotype.
Along the same lines, how can I predict what alleles the haploid egg would have? T or t? So, in that case, there would be a 50% chance of the embryo being TT and 50% chance of it being Tt (I didn't understand what the plus sign signifies).
The correct option is D, but I can't figure out how to get to that answer with absolute certainty.

The question is unclear to me. I understand we expect a triploid nucleus plus a diploid zygote (double fertilization) but I don't understand what (TTT + TTt), TT means.

IMO, the question is unclear
The question is unclear to me. I understand we expect a triploid nucleus plus a diploid zygote (double fertilization) but I don't understand what (TTT + TTt), TT means.

Which book did the question come from?
Is there any preamble to this question?

Double fertilization
I am not so used to thinking about double fertilization in plants. In short, two pollens are involved. One fertilize a haploid gamete from the mother and the other fuse with two haploid gamete (polar nuclei) from the mother (triple fusion) resulting in a triploid "individual".
In my below answer, I am assuming that any two polar nuclei can fuse with the pollen. I am not sure this is true. If it is systematically polar nuclei resulting from the same meiosis II (that is they have the same parent cell after meiosis I), then t story is a little different.
How I understand the question
In my understanding, we are talking about a single locus with two alleles T and t. Both pollens are T. The mother is Tt.
Answer
There are two possible gametes from the female side T and t. Only one possible gamete from the male side T. Therefore, the diploid zygote is either

$\frac{1}{2}$ TT
$\frac{1}{2}$ Tt

, where the numbers indicate probabilities
Now, for the triploid nucleus resulting from the fertilisation of two polar nucleus from the mother and one pollen grain can be either

$\frac{1}{4}$ TTT
$\frac{1}{2}$ TtT or tTT
$\frac{1}{4}$ ttT

Now, I have no idea how that matches to the possible answers as I don't understand the notation.


text:
Difference in ATP synthesis in mitochondria and chloroplast
The mechanism of ATP synthesis in mitochondria and chloroplasts are almost the same, but there is a big difference: the f1 particle in mitochondria uses 2 H+ ions to synthesize one ATP, whereas in chloroplasts the f1 particle uses 3 H+ ions for the same. What make the difference?

Any reference for f1 particle uses 2 protons?

It was mentioned in my text book, local  publication.

see this http://biology.stackexchange.com/questions/3186/given-atp-synthases-structure-how-can-3-33-protons-ultimately-synthesize-one-a

Does this mean that the ATP synthase works same in both mitochondria and chloroplast. But what I have read is that 1 NADPH in mitochondria is capable of sending 6 H+ ions in to the space between the two membranes of mitochondrial. And it obviously produces 3ATP , so 2H+ for one ATP.

1 NADPH does not produce exactly 3 ATP

Also NADH is used for atp synthesis not NADPH, and 1NADH pumps 10 protons , not 6 protons, provide any reference please.

This may help:http://www.madsci.org/posts/archives/1999-01/915551393.Bc.r.html

Reference: one of our coaching institute's book (akash).

So the book mentioned it wrong I will intimate them the same, and thanks for the link.


text:
Can defibrillation be done with a car battery?
Can successful defibrillation be done with a car battery? Is it POSSIBLE for this to work?
Let's say you are stuck on a very remote place and something happens to someone...
Moreover, can you jump start someone's heart using the battery of a car and the jumper cables, keeping in mind that:

in order to start a stopped heart you need electrical current applied in a short period, like 20 ms, and at a relatively high tension (200v) and small intensity?
car battery provides low tension current (12v) at a relative high intensity (70-80A) and the period cannot be 20 ms, but around 200-300 ms giving the fact that humans are not able to react that fast.

Welcome to BiologySE - you're going to have to give a little more research effort to try and figure out this question. Have you tried google to see what might be known about that? Your question would be better if you could add more to it - especially with some rationale

don't know what else can be added

in order to start a stopped heart you need electrical current. A battery has current. So...

Tension and Intensity can be slightly changed...

your above comments are useful - you should add them to your question... it's always helpful to show some research effort... http://biology.stackexchange.com/help/how-to-ask (also, you might want to clarify that you're interested in defibrillating the heart, which is only part of cardiopulmonary resuscitation)

I believe the type of current is not appropriate... at least when you need synchronized cardioversion. For defibrillation, possibly, but the problem would be to administer in a correct spatial fashion the current, and also delivering it precisely when appropriate.

You need to look up what CPR is - and also see defibrillation.

I did, my question was that if it is possible, not appropriate or 100% doable :)

CPR is not really about restarting the heart. See paragraph 3

defibrillation, good point

In general, no, but it is theoretically possible.
Car batteries are designed to provide a large amount of amperage, to turn the starter with a high amount of torque via an electric motor.  Generally this is done at 12 or 24 volts.
A common hospital-grade defibrillator (Zoll R-Series) has a battery pack that uses a 10.8V rechargeable lithium ion battery with a capacity of 5.8 amp-hours (per Zoll website/product data sheet). This battery is capable of providing 100 discharges (shocks) of 200J. A typical 12V car battery has a capacity of 40-65 amp-hours, so it could provide many more shocks if needed (I didn’t do the math to determine exactly how many more). You would need a way of controlling the current to deliver a shock of exactly 200-360J, which would be difficult to do without having the right equipment.
Defibrillation is usually performed starting at 200J, and then if needed subsequent shocks of 300J followed by 360J. Defibrillation uses direct current, so a battery is well-suited for this application as opposed to using alternating current from a wall outlet, which would need to be converted to direct current.
The point of defibrillation is not to provide power to the heart, it is to disrupt the heart's built-in electrical (biological) circuitry, when the heart is experiencing specific abnormal rhythms (ventricular fibrillation or polymorphic ventricular tachycardia).
Many cardiac events involve the heart beating in an uncoordinated manner, such that many or all of the muscle fibers in the heart beat in a manner that doesn't provide the squeezing action on the chambers to push the blood forwards.  Defibrillation seeks to correct such an uncoordinated beating by resetting the heart to rest, after which it will hopefully start beating again in a coordinated manner.
With this in mind, one could theoretically attach enough electrical transformation equipment to a car battery to use it as a power source for defibrillation.
Most defibrillators in hospitals are plugged into alternating current from a wall socket to charge the battery, and they are unplugged when they need to be used since the included battery can provide more than enough shocks before needing to be recharged.
So yes, a car battery could be used to power a defibrillator, but by itself it is not the right tool for the job.

Welcome to BiologySE... nice answer - we always appreciate some references that other users can go to for more information... if you could add those to your answer it would greatly strengthen it

@VanceLAlbaugh Feel free to edit and improve upon up my statement, and I understand the desire to make things into a "referenced encyclopedia" like format; but, I have have other goals in life.  If anyone wants to check any item above, they can use google.  If something was wrong with my answer, there'd be 20 guys crawling all over it telling me I was wrong anyway.

@EdwinBuck you may have other goals in life, but we expect answers here to be adequately sourced. Please read this meta post for discussion on this topic. Your answer may be flagged and removed if citations are not added.

Great and interesting answer--I was happy to read it despite the negative press covfefe,


text:
How do you test soil for the nutrients present in it?
I recently noticed that my rose garden has been in a very terrible state. The roses keep dying. I tested the soil for its pH and that was fine.
Now I'm wondering how would I carry out a test to see what specific nutrients I should use to get my soil better.

This question is probably more appropriate here: http://gardening.stackexchange.com/

I'm voting to close this question as off-topic because it should go to Gardening.SE

Send soil samples to a soil lab (e.g., here).
They will likely use the Mehlich III extractant   method to extract and quantify the nutrients (most importantly the bases such as  Ca, Mg, K, and Na). Will cost less than $25.

was the pH level from 6.0 to 7.4 ? because that is what plant life needs to dissolve nutrients easily


text:
Does this recording sound like the pulses emitted by bats?
Out of curiosity, I recorded sounds in an area with lots of bats, hoping to be able to "hear" the bats communicating by lowering the ultrasound to a level down to the frequency which can be heard by a human.
After a bit of post-processing, I actually hear interesting sounds, but I'm not sure about the origin. It seems that the frequency of the pulses is too low compared to bats.
The final audio is available on YouTube.
Are those actual sounds emitted by bats? If not, what other animal could be the source of those sounds?
About the audio
The sound was recorded at 10 p.m. at 46°34'32.0"N, 0°20'45.4"E near a river, with more of a dozen bats flying in this zone. There is a bridge nearby, and the sides of the river are flat concrete, which means that there are a lot of opportunity for sound reflection (although high frequency sounds don't reflect well).
Zoom H5 with the default XY directional microphone was used. The bitrate was set to 24-bit. Unfortunately, I used the sampling frequency of 48 kHz instead of the maximum 96 kHz.
The following transformations were made to the original audio:

The pitch was shifted by -12 semi-tones, which means that the 20 kHz sound becomes 10 kHz, and 15 kHz becomes 7.5 kHz.

All sounds below 6 kHz were removed.

The sound was amplified.

Severe noise reduction was applied to eliminate everything but the actual sounds emitted by the bats.

The empty parts of the audio were removed.

The sound was amplified once again.

Frequency
The frequency analysis of the transformed audio a peak around 9 kHz (18 kHz in the original audio), slowly fading to suddenly drop at 16 kHz (32 kHz in the original audio).

hypertextbook contains many sources with different indications about the frequency range of the sounds emitted by bats, only a few referencing the frequencies low enough to be heard by a human:

Frequency Produced 10kHz-120kHz
Ramsey, Gabriel, McGuirk, Phillips, Watenpaugh. Holt Physical Science. New York: Holt, Rinehart and Winston Publishers, 1986.

while most agreeing on the fact that bats use frequencies higher than 20 kHz.

Most bats use frequencies in the range 20-80 kHz, only a few bats use frequencies less than 20 kHz.
Long, M.R. & Savage, J.G. Mammal Evolution. New York: Harper, 1976: 108.

The observed range of 18..32 kHz seems too low compared to the sources, but I have an impression that the frequencies vary a lot between different species of bats.
Pattern
When viewing the audio track (see below), each cry consists of several pulses in two to three sub-groups which are in turn in two groups. Each peak is a bit less than 1 ms. The second group occurs from 40 to 200 ms. after the end of the first one. Each sub-group is separated by 5 to 10 ms.
The frequency of every pulse doesn't vary, except the very first pulse. The first cry starts by a more quiet pulse at 6 kHz (12 kHz in the original audio). The second and third cries don't follow this pattern.
Hyperphysics indicates that there are three categories of sounds emitted by the bats:

Short clicks,

Frequency-swept pulses,

Constant frequency pulses.

It looks like it's still the third category which we are observing here, and the overall pattern looks similar to the one described for the bats.
The gap between the left and the right track is mostly irrelevant: at higher frequencies, microphones become more and more directional, and the sound is reflected less, which leads to such difference.

Note: this question was considered to be on-topic at Biology.SE on Meta.

See Bat Detector. There are few examples of Bat calls.

Looks like the examples are not there anymore?

This is a good question (+1), but I think you should re-record the sounds with the appropriate sampling frequency. With a sampling frequency of 48 kHz, you are likely to get lots of aliased high-frequency noises (in the absence of lowpass filtering) which could hamper data analysis.

Should I add a bounty for this??

@DevashishDas; probably not now. I'll do very soon another records at 96 kHz, as suggested by March Ho above, and I'll also search for additional sources (especially books) which may be helpful.

ah, this is good mate

Just to add to your references: some bats can reach frequencies as low as 12 kHz and as high as 160+ kHz (Yalden & Morris, 1975).

Though I cannot be 100% sure from the sound quality, it certainly does sound/seem like bats are making the calls you are hearing/seeing. I spent a number of years as a bat bioacoustics researcher and I came across similar sounds frequently and was able to confirm they came from foraging bats.
I'll have to see if I can find any old spectrograms or recordings on an old data hard drive. If I can find clear examples similar to yours I will add them to my answer. (Though I haven't seen that hard drive in years, so don't get your hopes up!).
These sounds can likely be explained by one of the following:

Some bat species have been known to echolocate using calls that sweep into human hearing range (i.e., below 20kHz; Fenton, 2015; other sources already mentioned).

Many bats actually emit calls during flight that differ in structure from echolocation calls; these calls, often referred to as “social calls,” may occur between echolocation calls and often consist of broadband calls with low-frequency components and multiple syllables (Altringham and Fenton, 2003; Wright et al., 2013).

Some bats use special sounds to avoid collisions with each other while in flight (Fenton, 1983).

You can see and hear examples of some social calls (used broadly in this case) for a pipistrelle bat in Britain here.
I copy a spectrogram of one of these social calls from the above link (see the middle call signature):
Wright et al., 2013 also provide a spectrograph demonstrating all the various call signatures they recorded from various Eptesicus fuscus (big brown bats) in the United States:

Purchasing some bat bioacoustic analysis software should assist with your recordings and call interpretation. I recommend Sonobat (best, but expensive) or SCANR (from Binary Acoustic Technology). There are other less used options as well (e.g.,the Echo Meter Touch Bat Detector for Apple, for which I picture an example screen shot below):

I also want to provide some information and citations about bat echolocation to help inform those interested in this question:
Bat Acoustics 101

Shorter wavelengths (higher frequencies) provide a better resolution of target detail allowing the bat to receive a more detailed picture of its target (Fenton, 1983).

Acoustic energy reflected from a target is theoretically greatest when incident wavelengths of calls are near the same size or smaller than the target (Jones and Rydell, 2003); otherwise, if the object is smaller than the wavelength, the sound will be scattered instead of reflected (Yalden & Morris, 1975).

Bats need to be close to objects to "see" them: range is typically 1-5 m for frequencies around 20 kHz and increasingly closer for higher frequencies (Jones and Rydell, 2003).

In addition to target range, bats perceive target shape and texture from the delay of multiple reflections (echoes).

Calls contain base frequencies, but they can also add harmonics & overtones to the bandwidth of the calls, which can enhance target ranging and localization (Jones and Rydell, 2003) and thus increase acuity (Fenton, 1983). They can also suppress certain harmonics and use variations of combinations of tones.

Bats can also vary the amplitude, or loudness, of their calls (Yalden & Morris, 1975).

Bat calls can be composed of frequency modulated (FM) or constant frequency (CF) components or a combination of both types of calls (Jones and Rydell, 2003).

FM = each signal, consisting of discrete pulses of sound (Fenton, 1983), starts at one frequency and sweeps down to another. Sweeping through a range of frequencies allows bats to achieve some protection from errors associated with Doppler shifts; in addition, the modulation of frequencies helps to tell the bat about the texture of the target (Fenton, 1983).

While foraging, FM bats create a series of repeating ultrasonic pulses in various phases.  There are three major phases, each with an increase in repetition rate.   The change in rate across the phases can go from 4-5 pulses per second to 200 pulses per second.

The signals bats produce may serve multiple functions; they can be used for echolocation as well as for communication, whether intentionally or unintentionally.

Use echolocation calls of others to locate roosts, and eavesdropping also allows a territorial bat to distinguish between another bat trying to steal its food or just one passing through its territory (Fenton, 1983).

“Social calls" (Altringham and Fenton, 2003; Wright et al., 2013).

Collision avoidance sounds (Fenton, 1983).

Alarm calls and distress calls when in stressful situations.

Mother-young communication.


text:
What is the difference between disruptive, divergent and diversifying selection?
In our lab meeting we were chatting about divergent selection. I was confused at some point because I wasn't sure what was the meaning of this work in comparison to diversifying/disruptive and other types of selection.
Diversifying selection was coined by J. T. Gulick and I haven't found an interesting answer to compare with our contemporary definition of these terms.
The way I understand this is that, divergent selection is broader and include directional selection as well as disruptive selection. Is that correct?

I think you are conflating selection and evolution. Diversifying selection is when the variance of a trait in the population increases and even potentially becomes bimodal. This may lead to divergent evolution, i.e. a speciation event. Whereas directional selection still leads to evolution but not necessarily a the formation of a new species.

What about disruptive selection? It would be the same thing as divergent selection: the formation of a new species? Also, directional selection could also lead to the formation of a new species through anagenesis. In this case, what would be the differences?

I meant diversifying selection not divergent, I've edited my answer as such. Correct directional selection can also lead to speciation through anagenesis. The difference is that when a divergent evolutionary event occurs a new branch is formed (think Darwin's finches). Whereas, with anagenesis the current population changes so much it could longer mate with its "great great grandparents" but because their great great grandparents are longer around we do not consider this to be a branching of the phylogenetic tree.

So, following your answer, both mechanisms (disruptive and directional) could lead to the formation of a new species.
To think of it another way, disruptive selection would be that an intermediate trait has a lower fitness, but divergent selection would actually mean that the bimodal trait distribution is actually moving in opposite directions (i.e. opposing directional selection). Is that what you mean?

Yes that is a pretty good way to think about it.


text:
Success of computer simulations in biology, new discoveries
In an interview with Tim Hunt, Hunt makes the following comment:

There are some people nowadays who think you can sort of model everything on a computer. But I'm not one of those. I don't think anyone has actually discovered anything modeling something on the computer because there are so many different way of doing things...how Nature herself actually chose to do it.

The claim starts at 4'25'' in the link interview.
Have biological simulations ever led to biological discoveries? What purpose have they served?

I think this question is too broad and open-ended, and probably somewhat opinion-based in terms of what "discovery" means - though I'm open to a difference of opinion. As a neuroscientist, I'd say I definitely disagree with the idea that no one has actually discovered anything by modeling, but I also agree that there is a good deal of misinformation about what modeling can actually do, which leads to silly arguments for example from animal rights groups that imply scientists study animals just to torture them because they should be able to do everything on a computer...

I don't think the question is so specific to Biology but rather to the use of numerical modelling in science in general. IMO, the question is off-topic here and should rather be asked on Philosoiphy.SE.

Beware of people speaking outside their expertise, modeling is difficult in cellular mechanics becasue we only know a small fraction of what is going on and our current computers cannot even handle all of that at once. Of course protein structure prediction is fairly important modeling, which he studied, so he should still know better.

I think this is an appropriate question for biology and also I think that asking this question of biology is different from asking it of other scientific disciplines because there are many more data points in biology than there often are in, say, physics. Physics simulations could involve mere handfuls of atoms.  Biological simulations would be more complex.

Personally, I have not used computer simulations to "discover" but I've used them to identify which of the ideas I've developed a priori are possible.

I am happy to re-word the question, if possible.

I like the question, but it's a bad fit for this site. I agree with the closure. "Computational" is a vague term & arguably includes all biology. Hunt's own work is a series of models for biological systems. I am sure his students have gained insights from computational work along the way. In this case, I don't think Hunt understands what he is commenting on or, less cynically, is being too imprecise. For other scientists stepping out into another field and instantly falling over, see that Michio Kaku does not understand evolution.

seems that the answer is "yes": "Simulation reveals how bacterial organelle converts sunlight to chemical energy" https://www.sciencedaily.com/releases/2019/11/191114115845.htm

In my opinion, this question is a question of philosophy of science, not Biology but here are my thoughts anyway.
Science by definition is a methodology that requires the creation of a hypothesis under a specific model and testing the prediction of this particular hypothesis.
Such modelling can be done either analytically (math) or numerically (with a computer). Typically, numerical modelling is being used when there the mathematical tools fail to offer a solution for the system analyzed. To me rejecting, numerical modelling is like rejecting modelling and is therefore like rejecting the scientific method altogether.
Computational modelling has brought a lot in pretty much any field of biology (and pretty much any field of science), so much so that it is hard to know where to start to fully address this claim. There are many models that were only verbal as mathematical tools were not sufficient to bring more quantitative predictions. For many of these models, computer modelling could offer quantitative predictions that could then be further tested.

Hi Remi - congratz on reaching the #1 rep! Well done, mate :)

@AliceD Ha ha Thank you! I might not stay in this position for long as Chris and you are pretty close. The three highest reputed users are very close.

You're really gaining a lot of rep and you should be, as you're writing up a lot of good stuff. I'm hardly gaining any rep these days now I'm (pro-tem) mod on two sites :-)