Briefly describe how fossils are evidence of evolution. (FOSSILS)
Fossils show changes in species over long periods, revealing transitional forms that link ancient organisms to modern ones.
Briefly describe how vestigial structures are evidence of evolution. (VESTIGIAL)
Vestigial structures are reduced or unused features (e.g., human tailbone) that indicate ancestry with organisms in which the structures were functional.
Compare and contrast Darwinism and Lamarkism
Difference: Darwin proposed selection acting on inherited variation; Lamarck proposed inheritance of acquired characteristics.
Similarities: Both attempt to explain how organisms change over time.
Explain the process of selection. Provide an example of natural selection
What is selection: The process where certain traits become more common because they improve survival or reproduction.
Example of natural: Peppered moths becoming darker in polluted environments.
Provide an example of artificial and accidental selection
Example of artificial: Breeding dogs for specific traits like size or temperament.
Example of accidental: Insects becoming pesticide-resistant due to unintended environmental pressures.
Contrast with examples Stabilizing selection
stabilizing selection: Favours the average phenotype.
Example: Human birth weight (extremes are less viable).
Contrast with examples Directional selection
directional selection: Favours one extreme phenotype.
Example: Horses evolving larger body size over time
Contrast with examples Disruptive selection
disruptive selection: Favours both extremes over the average.
Example: Birds with very large or very small beaks surviving better than medium ones.
Provide an example of mutation (positive, negative, neutral)
positive mutation: CCR5-Δ32 mutation gives resistance to HIV.
negative mutation: Mutation causing cystic fibrosis.
neutral mutation: Change in DNA that doesn’t alter protein function (e.g., silent mutation in third codon position).
Provide definition and example of genetic drift
genetic drift: Random changes in allele frequency, especially in small populations.
Example: Founder effect on islands—few colonists carry only part of original gene pool.
Provide definition and example of gene flow
gene flow: Movement of alleles between populations through migration or interbreeding.
Example: Wolves from one pack migrating and breeding with a neighbouring pack, mixing genes.
Compare and contrast divergent evolution
divergent evolution: Related species become more different over time.
Example: Darwin’s finches developing different beak shapes.
key difference: Divergent = common ancestor → different traits
Compare and contrast convergent evolution
convergent evolution: Unrelated species evolve similar traits due to similar environments.
Example: Wings in birds and bats.
Key difference: Convergent = different ancestors → similar traits.
Define and provide examples of Coevolution
coevolution: When two species influence each other’s evolutionary changes.
Example: Flowers evolving nectar tubes matched by hummingbirds evolving long beaks; predator-prey “arms races” like cheetahs and gazelles.
