Chapter 22: Descent with modification, a Darwinian view of life 1. Identify Darwin and Wallace's contribution to the theory of evolution, and place it in the context of the ideas proposed previously 2. Explain five lines of evidence that support the theory of evolution: fossil record, biogeography, convergent evolution, direct observations (natural and artificial selection) and homologies 3. Describe the mechanism of natural selection 4. Define the following terms: descent with modification, homology, homologous structure, analogous structure, convergent evolution, fossil, vestigial structure, evolutionary tree, biogeography, artificial selection, adaptation, evolution

1. - They were the first ones to explain how species might change without individuals changing.

2. - Fossil record: It shows gradual change in life (transitional form).

Biogeography: It explains why certain species are found in certain areas of the world. It also explains why certain plants or animals or insects or living creatures are endemic in certain places.

Convergent Evolution: It explains why different lineages have to evolve similar traits to adapt to their environment.

Direct observation: a) Members of a species often vary in their inherited traits. This means that individuals that have a higher probability to survive have more offsprings. b) all species can produce more offsprings than their environment can support.

Homologies: Features present in an ancestral organism are altered by selection overtime in its descendents, resulting in overlying similarity, but different functions.

3. Natural Selection: a) Variation of heritable traits

b) Natural selection takes place (Competition and only the best will survive).

4. - a) Descent with modification: Phrase used by Darwing to say that species come for other species that were different from the original ones.

b) homologous structure: similarities in different species because they come from a similar ancestor (Mammalian forelimbs have the same basic skeleton is a homologous structure)

c) analogous structure: Charactestics shared in different lineages because of convergent evolution.

d) convergent evolution: the independent evolution in similar characteristics in different lineages (wings developed in bats and birds, dark/light patterned skin in dolphins and sharks).

e) fossil: the remains or traces of organisms of the past.

f) vestigial structure: Remnants of characteristics that served a function in the organism's ancestors (pelvic bones in a whale).

g) evolutionary tree: a diagram that reflects evolutionary relationships among groups of organisms.

h) biogeography: the study of geograhic distribution of species.

i) artificial selection: selection / breeding of individuals that have certain