AS91605 - Speciation

Demonstrate understanding of evolutionary processes leading to speciation

A species is a group of individuals which share a common ____ ____ and are ______________ isolated from other species.

gene pool, reproductively

Speciation ocurs when populations become ______________ ________ from other populations / the ancestral population.

reproductively isolated

A deme is a local population that has limited ____ ____ with members of the larger population.

gene flow

A cline is a pattern of variation between members of a species where there is a continuous increase or decrease in some phenotypic characteristics between ________ populations.

adjacent

The gene pool is the collection of all of the _______ in a population.

alleles

The three main processes contributing to evolution are ________, _______ _________, and ____ ____.

mutation, natural selection, and gene flow

Evolution over many generations results in __________.

speciation

evolution

change in pop gene pool over time

genetic drift affects _______ pops

smaller

stabilising selection

mid selected

disruptional selection

both extremes selected

directional selection

one extreme selected

nondisjunction

failure to pull apart chromosomes during cell division (usually meiosis)

allopolyploidy

2 species hybridise (hybrid infertile because chromosomes won’t pair or gametes won’t form), hybrid undergoes chromosome doubling (nondisjunction) so it is now fertile and can self-fertilise

autopolyploidy

nondisjunction produces unreduced gametes, individual can self-fertilise to form autopolyploid zygote

allopatric speciation

geographical isolation, different mutations with no gene flow over time lead to speciation

sympatric speciation

within same geographical location but any other RIM, diff mutations with no gf over time