Reproduction - the continuation of life processes

All organisms must reproduce for the species to survive BUT...This is the only life function not needed for the survival of the individual.

Remember a flower is actually a sex organ. It can be pistillate (female), staminate (male) or perfect. (both male and female)

The Two Types of Reproduction


  1. Two parents
  2. Both parents contribute DNA
  3. Insures variety within the species due to genetic diversity
  4. Each new offspring is genetically unique


  1. One mate is needed
  2. Genetically identical to parent
  3. NO genetic variation

One factor can wipe out an entire population. EX. antibiotics acting on bacteria



Asexual reproduction by Binary Fission (similar to mitosis)


Asexual reproduction by budding (unequal division of cytoplasm)


Sexual but can act as a male or female (monecious) That band you see close to the head is the clitelum, the female reproductive part. They also have testes.


Sexual (many develop outside the female in a true egg, similar to birds)


Sexual with either internal or external fertilization and development. The Great White Shark has both internal fertilization and development. The Salmon has both external ferilization and development. With external development many, many offspring will be produced. Salmon produce many million of offspring but only a few will survive to adulthood.


Sexual with internal fertilization BUT external development

Some mammals such as the marsupials and monotremes have evolved similar reproductive patterns but MOST are similar to humans


Sexual with internal fertilization and development these adaptaions were really important for survival in a terrestrial environment

Note the differences in Mitosis and Mieosis
Mitosis occurs in many different types of cells in the body and is used for growth and repair of tissue.
Mieosis ONLY occurs in the gonads to produce sex cells. (GAMETES)
Mitosis will produce two identical daughter cells with the same chromosome number as the parent cell. They are genetically the same.
Mieosis will produce cells with half the normal genetic information.
These new sex cells will also be different due to crossing over of homologous chromosomes.

Fertilization occurs in the oviduct or Fallopian tube and development occurs in the uterus

Human Reproduction Page


Plants can reproduce sexually and/or asexually.

Vegatative Propagation is the asexual form. This is as in natural means by bulb (tulip),tuber (potato), runner (strawberry) or rhizome (iris).
Note the differences between the stock and scion.
This is how we can get the Fruit Cocktail tree with many different types of fruits grafted on to the stock of one tree. Remember the only thing that will grow on the grafted scion is what the DNA in that scion is programmed to grow. It is amazing but you can graft a pear scion on to an apple tree stock and grow pears on that branch. Tru dat
Sexual reproduction in the plant can involve a sex organ called the flower as in the angiosperms. Remember a flower is actually a sex organ. It can be pistillate (female), staminate (male) or perfect. (both male and female)
Make sure you know the parts of the flower... Where is pollen made ?....What is pollination ?
What is germination?
Some plants like the Fern can alternate between sexual (gametophyte) and asexual (sporophyte) phases. The jellyfish do this also with the medusa (sexual) and polyp (asexual) phases.

Sex in Plants

Open Ended Question

  1. Explain how crossing over and sexual reproduction increase variety within a species
  2. 2. Write an essay explaining the meaning of each of the following terms and relate them to reproduction and development in humans; gametogenesis, zygote, fertilization, cleavage, blastula, differentiation and gastrula.
  3. 3. List in order the major stages of the human female menstrual cycle. State the chief events of each stage. Explain how the hormones, FSH, LH, estrogen, and progesterone are involved in female reproduction.