Explain the logic behind the claim that the nuclear envelope is a synapomorphy that defines eukaryotes as a monophyletic group.

The theory of common descent states that all modern organisms

a. Can change in response to environmental change

b. Descended from a single common ancestor

c. Descended from one of many ancestors that originally arose on Earth

d. Have not evolved

e. Can be arranged in a hierarchy from 'least evolved' to 'most evolved'

DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

a. Humans and chimpanzees share a relatively recent common ancestor.

b. Humans evolved from chimpanzees.

c. Chimpanzees evolved from humans.

d. Convergent evolution led to the DNA similarities.

According to data presented in this chapter, which of the following are correct? Select True or False for each statement. T/F When individuals change in response to challenges from the environment, their altered traits are passed on to offspring. T/F Species are created independently of each other and do not change over time. T/F Populations—not individuals—change when natural selection occurs. T/F The traits of populations become more perfect over time.

An adaptation is a trait of an organism that increases:

a. Its fitness

b. Its ability to survive and replicate

c. In frequency in a population over many generations

d. A and B are correct

e. A, B, and C are correct

The DNA sequence for the same gene found in several species of mammals_________.

a. Is identical among all species.

b. Is equally different between all pairs of mammal species.

c. Is more similar between closely related species than between distantly related species.

d. Provides evidence for the hypothesis of common descent

e. More than one of the above is correct.

Some biologists summarize evolution by natural selection with the phrase "mutation proposes, selection disposes." Mutation is a process that creates heritable variation. Explain what the phrase means.

Although cellulose and starch are identical in terms of stored chemical energy, our ability to harvest the energy from these two polysaccharides differs considerably. What is responsible for this difference?