Chapter 19 - Answers to End-of-Chapter Questions


TO REVIEW

1. A fossil is any evidence of a formerly living organism.

2. Answers will vary.

3. A cladogram depicts how ancestral species diversified and branched into different species.

4a. Lower rock strata are older than higher rock strata.
b. Radioactive decay is an absolute; the half-life is not alterable.
c. Mutation occur at predictable rates.

5. Embryological origins. Species relatedness.

6. Answers will vary.

7. One possible answer: Relative and absolute data deal with the effect; molecular data deal with the cause.

8. Looking for conserved sequences.

9. DNA sequences, processes of protein synthesis, etc. The major limitation is that this information is not absolute.


TO THINK ABOUT

1a. Answers will vary.
b. Betazoids. Branching is closest, chromosome band correspondence.
c. Answer could go either way. The definition of species -- from Chapter 18 -- states that the organisms do not interbreed under normal circumstances. That would make them all separate species. All these organisms can interbreed; and humans fall in love with the darndest creatures! Is love a normal circumstance? If it is, we are all one species! Think about the hybrids mentioned in Chapter 18.
d. c

2. Answers will vary.

3a. H. verrucosa
b. Tobacco
c. Algae

4. No, this does not mean that chimps are humans or that humans with different alleles are different species. One other explanation is that the genes involved are not essential for species distinction.

5. One way would be to trace Y chromosome sequences. Other answers are possible.

6. Any one gene can mutate. Other answers are possible.

7. Answers will vary.

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