In science, a theory is:

a. an untested hypothesis.

b. a general set of principles, supported by evidence, that explains some aspect of the natural world.

c. speculation about the natural world, based on general knowledge of a field.

d. an observation.

e. the first idea proposed to explain some aspect of the natural world.

Which of the following are central ideas in the theory of evolution by natural selection? (List all that apply.)

a. Organisms vary in traits that affect their reproduction.

b. Descent with modification occurs over generations.

c. Evolution has a goal.

d. Traits that confer a reproductive advantage will become more common in populations over time.

e. Traits that are acquired during the life of an individual contribute to evolution.

Which of the following observations provide evidence for evolution? (List all that apply.)

a. Monkey and trilobite fossils are never found in the same fossil beds.

b. Athletic training can produce an increase in muscle mass.

c. DNA sequences of genes shared by various species vary in accordance with predictions about how closely related those species are.

d. The genetic code is nearly universal.

e. Species whose adult forms look very different may have similar features in embryonic life.

Some of the following structures are homologous with each other. Which ones are they, and which two do not belong to this group?

a. whale flipper

b. insect leg

c. bat wing

d. cat forelimb

e. octopus tentacles

Discoveries in the field of __________ provided key evidence needed for natural selection to be widely accepted as the mechanism of evolution (select one).

a. radiometric dating

b. fossils

c. genetics

d. DNA sequencing

e. medicine

Important implications of the theory of evolution by natural selection include (select all that apply):

a. All organisms, including humans, are descended from a common ancestor.

b. The biological world is constantly evolving.

c. Nature designs things intentionally.

d. Traits found in organisms are the outcomes of a goal-less process.

e. Humans occupy one ordinary branch on an enormous tree of life.

John Endler performed an experiment involving guppies in which he demonstrated evolution driven by natural selection that worked through a predator-prey relationship. Which of the following are true statements about the results of his experiments? (Select all that are correct.)

a. Males with longer tails and brighter coloration were more frequently eaten by predator fish.

b. Females preferred to mate with dull- colored males.

c. When males were put in a predator- free environment, brighter coloration and larger tails evolved in them.

d. In the predator-free environment, the average brightness of females increased.

e. When predators were reintroduced, duller coloration and smaller tails evolved in the males.

PCR has been described as a copying machine for _______.

In forensic biotechnology, the value of PCR is that it allows the establishment of identities based on _____ samples of DNA.

The DNA of every individual contains groups of ________ whose number can be used to establish the identity of that individual.