Week 13

Prior to the publication of Charles Darwin's book, On the Origin of Species, what was the prevailing public consensus regarding species evolution?

That species were permanent and unchanging

The human immune system cannot effectively suppress the HIV virus on its own. What key feature of HIV makes it so hard to beat?

The HIV virus has an extremely high rate of mutation.

HIV has become an important source of mortality for humans. If AIDS persists as a major factor for humans for many generations in the future, natural selection theory predicts that _____.

any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time

Comparing the body structures of organisms to find evidence of a shared evolutionary history is called ________.

comparative anatomy

The older fossils are typically found in the ________ sediments.

lower

What is the smallest unit that can evolve?

population

Individuals with variations that make them best suited to their environment will, on average, be more likely to ________.

survive and reproduce

A straggler with green eyes stumbles into the last remaining human outpost. The green eye trait did not exist in the outpost before her arrival, but it does now. What is the name of this mechanism of evolution?

Gene flow

As proposed by Darwin, what sorts of traits are favored by natural selection?

Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

What does "fitness" mean when speaking in terms of evolution?

How many offspring an individual produces

Why or why is it not accurate to say that individuals evolve?

It is not accurate because the evolution of one individual would not affect the entire species.

What is the original source of variation?

Mutation

What is the name for the study of the geographic distribution of species?

Biogeography

Why is it inaccurate to say that humans are the most highly evolved species?

Both

Imagine that four people are infected with HIV from a common source (an infected blood sample). Initially, the patients' HIV populations are genetically identical. By the time they develop full-blown AIDS, how would the viral populations of the four patients compare?

Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses.

What is radiometric dating?

The process of determining the age of the fossils from radioactive isotopes

Natural selection is best described as _____.

a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations