Exam 5: Adaptation and Natural Selection

An organism's structure and ________ reflect adaptations to its particular environment.

A gradual change in phenotype across an environmental gradient,such as white-tailed deer changing gradually in size from large in the north to small in the south,is referred to as

Inbreeding is usually beneficial to a population because it increases genetic diversity.

A gene is

All of the DNA in a cell is collectively called the ________.

________ mating occurs when individuals choose mates nonrandomly with respect to some phenotypic trait.

Which of the following characteristics is an example of a qualitative trait?

The color of a flower is controlled by two alternative alleles at a single locus,R (red)and r (white).If an individual has the Rr alleles,it is considered to be

The selective agent is the environmental cause of fitness differences among organisms with different phenotypes.

The alternate forms of a gene are called

The sum of genetic information (alleles)across all individuals in a population at any one time is called the ________.

Variation within and among species would increase dramatically if the environment were homogeneous.

What is the primary original source of genetic variation in a population?

Measurements of bill length in a population of seed-eating birds reveals two distinct groups: small-billed individuals feeding on soft-shelled seeds and large-billed individuals feeding on hard-shelled seeds.This bimodal distribution most likely resulted from

Reversible phenotypic changes in an individual organism in response to changing environmental conditions are referred to as ________.

The effect of positive assortative mating is to