Mastering Biology Chapter 22

Which of the following scientists argued that variation among individuals allows evolution to occur?

Wallace

direct observation of evolutionary change (example)

- development of drug resistance in bacteria

fossil record (example)

- discovery of shells of extinct species - discovery of transitional forms of horses

homology (example)

- similarities in mammalian forelimbs - same genetic code in fireflies and tobacco plants - vestigial pelvis in right whales

biogeography (example)

- the high concentration of marsupial species in Australia - similarity of endemic island species to nearby mainland species

Which of the following is not an observation or inference on which natural selection is based?

Poorly adapted individuals never produce offspring.

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____.

a vestigial trait

A population of organisms will not evolve if _____.

all individual variation is due only to environmental factors

The role that humans play in artificial selection is to _____.

choose which organisms reproduce

A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____.

embryos of dissimilar organisms, such as sharks and humans, resemble each other

Darwin and Wallace were the first to propose _____.

natural selection as the mechanism of evolution

From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.

organisms had adapted to new environments, giving rise to new species

Charles Darwin

proposed natural selection as the mechanism of evolution