The Smallest Unit of Evolution

Which of the following is a common misconception about evolution?

Individual organisms can evolve (correct)

Natural selection acts on populations

Only populations can evolve

Genetic drift causes adaptive evolution

What is microevolution?

The flow of genes between populations

The isolation of a population from others

The process of genetic drift

A change in allele frequencies in a population over generations (correct)

Which of the following is NOT one of the main mechanisms that cause allele frequency change?

Genetic drift

Mutation (correct)

Gene flow

Natural selection

Which mechanism consistently causes adaptive evolution?

Natural selection Signup and view all the answers

What is a prerequisite for evolution by natural selection?

Variation in heritable traits Signup and view all the answers

What is the smallest unit of evolution, according to the text?

Populations Signup and view all the answers

What is the main factor that causes allele frequency change due to random events?

Genetic drift Signup and view all the answers

What is the term used to describe the flow of genes between populations?

Gene flow Signup and view all the answers

What is the main mechanism of evolution that acts on individuals?

Natural selection Signup and view all the answers

Which figure in the text provides evidence of selection by food source?

Figure 21.2 Signup and view all the answers

According to Mendel's work on pea plants, what did it provide evidence of?

Discrete heritable units Signup and view all the answers

What does genetic variation reflect?

Phenotypic variation Signup and view all the answers

What is genetic variation?

Differences in gene composition among individuals Signup and view all the answers

How are some phenotypic differences classified?

On an 'either-or' basis Signup and view all the answers

What determines traits that can be classified on an 'either-or' basis?

A single gene Signup and view all the answers

What causes other phenotypic differences that vary along a continuum?

Influence of many genes Signup and view all the answers

How can genetic variation be measured at the molecular level?

Nucleotide variability Signup and view all the answers

Where do most nucleotide variations occur?

Noncoding regions (introns) Signup and view all the answers

Do variations in coding regions (exons) affect the protein's sequence of amino acids?

Rarely Signup and view all the answers

What does Figure 21.4 show about genetic variation at the molecular level?

Extensive genetic variation Signup and view all the answers