Evidence for Evolution Worksheet (Answers)

Evidence for Evolution Evolutionary Theory Define evolution Evolution is the cumulative change in the heritable characteristics of a population ………………………………………………………………………………………………………………………………………………….......... It is a change in the allele frequency of a gene pool across successive generations ………………………………………………………………………………………………………………………………………………….......... With the aid of the diagram, compare the evolutionary theories of Lamarck and Darwin Lamarck proposed that organisms evolved new characteristics as a consequence of habitual use or disuse ………………………………………………………………………………………………………………………………………………….......... (e.g. giraffes evolved long necks via stretching to reach higher leaves) ………………………………………………………………………………………………………………………………………………….......... Darwin proposed that organisms randomly developed new characteristics that were passed on for being beneficial ………………………………………………………………………………………………………………………………………………….......... (e.g. long neck giraffes survived over short neck giraffes because they could reach more leaves) ………………………………………………………………………………………………………………………………………………….......... Distinguish between natural selection and artificial selection Natural selection occurs when the environment determines which adaptations are beneficial or detrimental ………………………………………………………………………………………………………………………………………………….......... Artificial selection occurs when humans make this determination (via genetic modification or selective breeding) ………………………………………………………………………………………………………………………………………………….......... Evolutionary Evidence Outline the evidence for evolution provided by the fossil record A fossil is the preserved remain or trace of an organism from the remote past (totality of fossils = fossil record) ………………………………………………………………………………………………………………………………………………….......... The fossil record shows that changes have occurred in organisms over time (evolution) ………………………………………………………………………………………………………………………………………………….......... The law of fossil succession shows that certain organisms appear in the fossil record in a consistent order ………………………………………………………………………………………………………………………………………………….......... (this indicates an evolutionary sequence of development from ancestral forms) ………………………………………………………………………………………………………………………………………………….......... Transitional fossils represent intermediary forms within the evolution of a genus (e.g. archaeopteryx) ………………………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... With the aid of the diagram, describe the process of fossilisation Fossilisation preserves hard body parts (although soft parts may leave trace remains - such as imprints) ………………………………………………………………………………………………………………………………………………….......... Fossilisation is a rare process that requires the preservation of remains (i.e. no scavenging), anoxic conditions ………………………………………………………………………………………………………………………………………………….......... (i.e. no oxygen for decomposition) and high pressure (to turn the hard body parts into fossilised minerals) ………………………………………………………………………………………………………………………………………………….......... These conditions are most likely to occur (on land) as a result of rapid burial ………………………………………………………………………………………………………………………………………………….......... Outline, with examples, the evidence for evolution provided by selective breeding Selective breeding involves the intentional mating of animals with desired characteristics (artificial selection) ………………………………………………………………………………………………………………………………………………….......... As human intervention drives the selection process, changes will occur over fewer generations and will promote ………………………………………………………………………………………………………………………………………………….......... the evolution of phenotypic extremes (hence, easier to identify the evolutionary pathway) ………………………………………………………………………………………………………………………………………………….......... Examples: Horses (bred for speed vs power), cows (Belgian blue = muscle mass), large variations in dog breeds ………………………………………………………………………………………………………………………………………………….......... Explain, using the diagram, how the pentadactyl limbs of vertebrates provides evidence of evolution Homologous structures are anatomical features that share a common underlying structure despite having distinct ………………………………………………………………………………………………………………………………………………….......... functions - the pentadactyl limb of mammals is an example of a homologous structure ………………………………………………………………………………………………………………………………………………….......... The rapid diversification of the anatomical feature is a result of adaptive radiation ………………………………………………………………………………………………………………………………………………….......... Closely related species will have more similarities in their homologous structures …………………………………………………………………………………………………………………………………………………..........