Biology Quizzes Ch 22-25

You have excavated a sample you suspect is about 20,000 years old. What radioactive isotope will you use to date the sample?

Carbon-14

According to the punctuated equilibrium model

Most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. which of the following is the most likely explanation for these data?

Natural selection in the aquatic environment resulted in significant changes to whale forelimb anatomy.

What is half-life?

The time required for half of a radioactive parent isotope to decay to its respective daughter isotope, on average.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?

The two forms interbreed often in nature, and their offspring have good survival and reproduction.

Which of the following is not an observation or inference on which natural selection is based?

Which of the following is not an observation or inference on which natural selection is based?

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:

humans and chimpanzees share a relatively recent common ancestor.

No two people are genetically identical, except for identical twins. The chief cause of genetic variation among human individuals is:

the reshuffling of alleles in sexual reproduction

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?

.42

Suppose you are studying two bird species that live in a forest and are not known to interbreed. One species feeds and mates in the treetops and the other on the ground. But in captivity, the birds can interbreed and produce viable, fertile offspring. What type of reproductive barrier most likely keeps these species separate in nature?

Behavioral isolation

What did early researchers hypothesize as the source of energy for making organic molecules?

Electricity from storms and/or UV radiation

Which of the following factors would not contribute to allopatric speciation?

Gene flow between the two populations is extensive.

How did Hutton's and Lyell's ideas influence Darwin's thinking about evolution?

Hutton and Lyell perceived that changes in Earth's surface can result from slow, continuous actions still operating at the present time.

How does Lamarckian evolution compare to the Darwinian model?

Lamarck proposed that species evolve resulting from use or disuse of a trait with immediate heritability. Darwinian evolution focuses on the success of a trait.

What elements did researchers in the 1920s believe the early atmosphere contained?

Nitrogen, ammonia and methane, among others.

Of all the mutations that occur in a population, why do only a small fraction become widespread among the population's members?

Only a small fraction is advantageous to population's members.

If a mass extinction were caused by a single, catastrophic event (such as asteroid impact), what pattern would you expect regarding the dates when formerly common species lost in the extinction are last observed in the fossil record?

Theoretically, these fossils should be observed right up to the extinction event.

Natural selection changes allele frequencies because some ________ survive and reproduce more successfully than others.

individuals

If p is the frequency of allele A, which parts of the Hardy-Weinberg equation correspond to the frequency of individuals that have at least one A allele?

p + half of 2pq