State whether the following statements is true/false regarding DNA replication.

1. The polymerization of DNA is essentially irreversible due to the hydrolysis of pyrophosphate.

2. On average about twenty errors are made during each replication of the human genome.

3. DNA polymerase I possesses 5ʹ → 3ʹ exonuclease activity.

4. All DNA ligase enzymes use ATP as a cosubstrate.

5. The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions.

#Question id: 4640

#Unit 11. Evolution and Behavior

During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection?

#Question id: 4641

#Unit 11. Evolution and Behavior

Which of the following statements is an inference of natural selection?

#Question id: 4642

#Unit 11. Evolution and Behavior

Which of Darwinʹs ideas had the strongest connection to Darwin having read Malthusʹs essay on human population growth?

#Question id: 4643

#Unit 11. Evolution and Behavior

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

How many separate species, both extant and extinct, are depicted in this tree?

#Question id: 4644

#Unit 11. Evolution and Behavior

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

According to this tree, what percent of the species seem to be extant (i.e., not extinct)?

#Question id: 4645

#Unit 11. Evolution and Behavior

The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct?