Macroevolution

Question 1

Macroevolution

Answer 1

Evolution of groups larger than an individual

Question 2

Rates of evolutionary change

Answer 2

Gradualism - evolution proceeds slowly and continuously over long periods of time through the accumulation of small, incremental changes

Punctuated equilibrium - evolution occurs in relatively short bursts of rapid change, separated by long periods of stasis

Question 3

Why do gaps appear in the fossil record?

Answer 3

Fossilization is rare, it requires:
-Death - inevitable
-Burial with organism mostly intact - rare due to scavenging and decay
-Sedimentation - rare in terrestrial environments
-Survival of sedimentary rocks - rare, geologic processes repeatedly destroy sedimentary layers

Question 4

Can selection explain differences in rates of evolution?

Answer 4

Selection can explain rapid change and stasis

Rapid change
-The frequency of the advantageous trait will increase rapidly in the population over time, leading to a rapid change in the population’s genetic makeup

Stasis
-traits that are currently favoured by selection are already well-adapted to the environment. In this case, there may be little selection pressure for change in the population, leading to stasis

Question 5

Convergent evolution

Answer 5

The independent evolution of similar features in different groups of organisms that do not share a recent common ancestor. This can occur when different organisms face similar ecological or environmental pressures and, as a result, evolve similar adaptations to survive