evolution

Question 1

What is allopatric speciation?

Answer 1

Evolution of a new species from demes isolated in different geographical locations.
Speciation caused by any mechanism of geographically separating demes e.g. species isolated by mountain ranges, deserts, oceans, rivers etc.

Question 2

What are demes?

Answer 2

A sub-group of a population that interbreed more frequently, reducing gene flow with the rest of the population.

Question 3

What is behavioural isolation?

Answer 3

Demes with differing courtship rituals will not interbreed and become isolated.

Question 4

What is seasonal isolation?

Answer 4

Demes with different breeding seasons cannot interbreed and become isolated.

Question 5

What is hybrid fertility?

Answer 5

Some plants can double their chromosome number by endomitosis to become fertile.

Question 6

What is sympatric speciation?

Answer 6

Evolution of a new species from demes sharing the same geographical location.

Question 7

What is morphological isolation?

Answer 7

If the genitalia of demes are incompatible, they cannot interbreed.

Question 8

What is hybrid sterility?

Answer 8

When two different species are similar enough to breed, they can produce hybrid offspring, but these are often sterile and unable to breed themselves.
This could be due to an uneven chromosome number e.g. Mules have 63 chromosomes which cannot form homologous pairs during prophase I in meiosis and so gametes cannot be formed.