click below
click below
Normal Size Small Size show me how
Advanced Higher
Unit 2 - Evolution
| Question | Answer |
|---|---|
| What is the definition for evolution? | Evolution is the change over time in the proportion of individuals in a population differing in one or more inherited traits. |
| What are the two non-random processes that can cause evolution to occur. | Natural selection and sexual selection |
| Which non-random process increases the frequency of alleles that increase reproductive chances? | Sexual selection |
| Which non-random process increases the frequency of alleles that makes survival more likely? | Natural selection |
| Is genetic drift random or non-random? | Random |
| Genetic drift has a greater effect on ________________? and why? | Small populations, as alleles are more likely to be lost from the gene pool. |
| What is absolute fitness? | The ratio of frequencies of a particular genotypes from one generation to the next. |
| What is relative fitness? | The ratio of surviving offspring of one genotype compared with other genotypes. |
| What are the three different forms of mutation that cause novel alleles? | Neutral, harmful, beneficial |
| Which factors can affect the rate of evolution? | Horizontal gene transfer, warmer environments, shorter generation times, sharing of beneficial DNA sequences through sexual reproduction. |
| Give an example of two species that co evolve. | Herbivores and plants; pollinators and plants; predators and their prey; parasites and their hosts. |
| Variation in traits arises as a result of? | Mutations |
| Define natural selection. | Increased selection pressure for favourable alleles that can survive and reproduce. |
| Which types of mutation are more likely to occur? | Neutral and harmful |
| Explain the term Co-evolution | Occurs in organisms that interact frequently. They are interdependent on one another |
| Explain what is meant by an evolutionary arms race | One species increases selection pressure for competitor to evolve |
| Explain the Red Queen hypothesis | Occurs in organisms that interact frequently. A change in a particular trait acts as a selection pressure on the other species. |