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Key Questions

  • Answer:

    Its when a species of an animal changes in such a way that they are no longer able to mate with the original species


    There are different type ( temporal, geographical...) they might just mate at a different time in the year, live in a different area, no longer able to mate ( reproductive size or systems)

  • Answer:

    It is one type of way through which a new species is created.


    This is a unique type of speciation in which new species are created out of a preexisting species.

    There are no physical barriers which seperate members of an existing species like in allopatric speciation(another way of new species are created).

    Sympatric speciation is rare and is more common in plants than in animals.

    It happens in plants when, due to some error during reproduction, offspring is produced that contains twice the number of normal chromosomes.

    • We say that a normal cell is di ploid since it has two copies of each chromosome(one from each parent).
    • But this certain offspring has four copies of each chromosome-hence it is called tetra ploid.

    This process of getting more chromosomes than normal is given a fancy name Polyploidy.

    This is an example of polyploidy in a cell with diploid number 6.

    • As a general rule, when two things can't mate, it means they are not of the same species.
    • A tetraploid plant cannot mate with a diploid plant.
    • Hence, both are different species. And a new species, the tetraploid is made.

    A tetraploid plant can reproduce asexually though, and that's how it's species continues.

    Following is a real world example of sympatric speciation in animals :

    It involves the apple maggot fly shown here:


    The apple maggot fly lays it's eggs inside an apple causing it to rot.
    The maggot originally laid it's eggs in a fruit called a hawthorn.
    When apples trees were planted in North America in the 19th century, a maggot species evolved that laids its eggs only in apples, not in hawthorns.
    The maggot flies that lay their eggs in apples, mate with the flies that also lay their eggs in apples; the same is true for flies that lay eggs in hawthorns.

    So a new species of maggots has been created that lays it's eggs in apples, instead of hawthorns.

    There are four more types of speciation (ways in which new species are formed).

    • Allopatric
    • Peripatric
    • Parapatric
    • Artificial

    If you want to learn more about these types of speciation (I know you do), go to http://science.howstuffworks.com/life/evolution/evolve-in-isolation1.htm

  • Speciation
    The speciation is the fact that two different populations of a same specie leads to 2 news species.

    Allopatric speciation
    Allopatric speciation can occurs when populations of a same specie are geographically separated, so genetics exchanges are not possible any longer.By living in different places, they have to face different environmental conditions (heat, salinity, pH ...) and so to adapt differently. Becoming slightly differently generation by generation, they will become so different that they won't be able to breed if they were in the same place again.

    The Darwin's finches are a good example of allopatric speciation !


    (Biology 2108 Lecture Evolution: Macro-evolutionary processes)

    Enjoy your day !