Natural Selection and Speciation 0.0 / 5 ? BiologyEcology, ecosystems and environmental biologyA2/A-levelEdexcel Created by: francesca_321Created on: 31-12-15 13:20 In a population of organisms what happens to produce what? random mutations produce new alleles 1 of 16 so therefore what does this cause? new variation 2 of 16 therefore what do individuals in populations have? different genotypes and show genetic variation 3 of 16 What happens if there is a change in environment? some genotypes may make organisms more likely to survive long enough to reproduce 4 of 16 What would they pass on? particular alleles on to their offspring 5 of 16 What happens to the other organisms? the ones less adapted will die from predation, competition for food and disease 6 of 16 Those that reproduce will have offspring that? some of which will inherit the favourable alleles in their genotypes 7 of 16 What will happen over time? proportion of individuals with favourable genotypes will increase in the population. 8 of 16 What happens to a group of individuals? a population somehow get separated and reproductively isolated from the rest of the population so they cannot breed with them. 9 of 16 What does each population accumulate? different random mutations so the different genes pools may contain different alleles. 10 of 16 Why might the variations be reduced? some alleles may be lost by genetic drift and genetic diversity may be reduced by inbreeding 11 of 16 What is each population exposed to? different selection pressures in their habitats 12 of 16 What are individuals survive? genotypes that enable them to survive to breed will pass their alleles on to the next generation 13 of 16 What does it change? frequencies of a particular allele 14 of 16 What happens over time? results in individuals in each population becoming specifically adapted to their new environments 15 of 16 What happens when individuals have changed so much? they can no longer interbreed successfully, changes in breeding behaviour, timing of breeding etc 16 of 16
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