Understanding the Effect of Adaption & Selection on a Population

Question 1

Adaptation and selection contribute to the large diversity of living organisms and are major factors in the process of evolution

Evolution is the

Answer 1

change in adaptive features of a population over time as a result of natural selection

Question 2

If an environment is static and does not change, then selection pressures will not change and evolution will not occur

If the environment changes or a chance mutation produces a new allele, selection pressures may favour ……………

Answer 2

individuals with different characteristics or with the new allele

Question 3

Natural selection results in a process of adaptation, which means that, over generations, those features that are better adapted to the environment become more common

This means whole populations of organisms become better suited to the

Answer 3

environment

Question 4

How to know when two population of the species have been isolated and are not the same species anymore

Answer 4

If two populations of one species are isolated from each other and become so different in phenotype that they can no longer interbreed to produce fertile offspring, they have formed two new species

homologous pairs don’t match up m

Question 5

The formation of new species (speciation) from pre-existing species over time, is a result of accumulated genetic differences
Evolution drives speciation and so is responsible for the large number of species that exist on earth

Question 6

There are many examples of natural selection and evolution but they ALL follow the same sequence:

Within a species, there is always variation and chance mutation
Some individuals will develop a phenotype (characteristic) that gives them a survival advantage and this allows them to:
live longer
breed more
be more likely to pass their genes on
Repeated over generations, the ‘mutated’ phenotype will become the norm

If genetic differences accumulate and the population is isolated then a new species may evolve

Remember, it is the concept you have to understand, not a specific example. You will be expected to use unfamiliar information to explain how selection produces changes within a population of a species and interpret data relating to the effect of selection in producing change within populations.