Speciation

Question 1

define species

Answer 1

group of closely related individuals who have similar physiology, morphology and behaviour. They interbreed to produce fertile offspring and they are not reproductively isolated.

Question 2

what are the two types of speciation

Answer 2

allopatric isolation
sympatric isolation

Question 3

what is allopatric isolation

Answer 3

isolation is by a geographical feature such as a mountain range, river or ocean

Question 4

what is sympatric isolation

Answer 4

isolation may be by a mutation occurring in some individuals, causing them to be reproductively isolated e.g. difference in behaviour

Question 5

what are some methods of isolation

Answer 5

ecological isolation - species occupy different parts of the habitat
temporal isolation - species lives in the same area but reproduce at different times
behavioural isolation - species live in the same area but do not recognise each others behaviour
physical incompatibility - species co-exist but physical reasons prevent copulation
gametic isolation - male and female gametes cannot fuse to combine genetic information

Question 6

how different species arise

Answer 6

by natural selection
-organisms with alleles for characteristics that make them well adapted to conditions in the habitat to survive, reproduce and pass on these alleles
-overtime organisms in the two groups become less like each other
-eventually if two groups were to meet again they would not be able to interbreed
-differences between two organisms are now too great to allow breeding to produce fertile offspring
-two organisms have become separate species

Question 7

what is reproductive isolation

Answer 7

-no interbreeding between two species
-due to a geographical barrier
-or different behaviour
-or incompatible genitalia
-each population has a different gene pool/alleles/mutations/restricted gene flow