Biology Exam #4

Question 1

What is adaption?

Answer 1

the process by which a species becomes fitted to its environment

Question 2

What is a allele?

Answer 2

One of two or more DNA sequences occurring at a particular gene locus.

Question 3

What is codominance?

Answer 3

a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual

Question 4

What is disruptive selection?

Answer 4

also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values.

Question 5

What is evolution?

Answer 5

the change in heritable traits of biological populations over successive generations.

Question 6

What is Genetic Drift?

Answer 6

the change in frequency of an existing gene variant in the population due to random chance.

Question 7

What is genotype?

Answer 7

It can be represented by symbols. For example, BB, Bb, bb could be used to represent a given variant in a gene.

Question 8

What is heterozygous?

Answer 8

The presence of two different alleles at a particular gene locus. Bb

Question 9

What is homozygous?

Answer 9

The presence of two identical alleles at a particular gene locus. bb, BB

Question 10

Incomplete Dominance

Answer 10

results from a cross in which each parental contribution, unique, neither phenotype is present

Question 11

Macroevolution

Answer 11

evolution above the level of species.

Question 12

Microevolution

Answer 12

simply a change in gene frequency within a population.

Question 13

Mutation

Answer 13

Any change in the DNA sequence of a cell. It may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment.

Question 14

Phenotype

Answer 14

The observable characteristics in an individual resulting from the expression of genes; the clinical presentation of an individual with a particular genotype.

Question 15

Polygenic Inheritance

Answer 15

quantitative inheritance, where multiple independent genes have an additive or similar effect on a single quantitative trait.

Question 16

Population

Answer 16

a group of individuals of the same species living and interbreeding within a given area

Question 17

Punnett Square

Answer 17

a table in which all of the possible outcomes for a genetic cross between two individuals with known genotypes are given.

Question 18

Reproductive Isolation

Answer 18

the inability of a species to breed successfully with related species due to geographical

Question 19

Sexual Selection

Answer 19

The process by which certain organisms produce more offspring by mating more frequently than other organisms of the same sex and thereby ensure the survival of more of their genetic traits.

Question 20

Stabilizing Selection

Answer 20

a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value.

Question 21

True-breeding

Answer 21

sometimes also called a purebred (biology slang: pure line or true-breeding line), is an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring of many generations.

Question 22

Law of Independent Assortment

Answer 22

describes how different genes independently separate from one another when reproductive cells develop.

Question 23

Law of Segregation

Answer 23

describes how pairs of gene variants are separated into reproductive cells.

Question 24

Monohybrid

Answer 24

an individual or strain heterozygous for one specified gene.

Question 25

Dihybrid

Answer 25

a mating experiment between two organisms that are identically hybrid for two traits. A hybrid organism is one that is heterozygous, which means that is carries two different alleles at a particular genetic position, or locus