Chapter 8: Evolution

Question 1

Evolution

Answer 1

A genetic change in a population over time

Question 2

Four Types of Evolution

Answer 2

Mutation, genetic drift, migration, and natural selection

Question 3

Mutation

Answer 3

An alteration of the of the base pair sequence of an individuals DNA

Question 4

Genetic Drift

Answer 4

A random change in allele frequencies in a population

Question 5

Fixation

Answer 5

Results when an alleles frequency in a population reaches 100%

Question 6

Founder Effect

Answer 6

May have different allele frequencies than the original population. If the new population has different allele frequencies evolution has occurred

Question 7

Population Bottleneck Effect

Answer 7

When large proportions of a population dies the allele frequencies may not be the same as the original population

Question 8

Migration

Answer 8

Is the movement of some individuals of a species from one population to another. This movement may cause a change in the allele frequencies of the population

Question 9

Natural Selection

Answer 9

There must be variation for the trait within a population, the variation must be heritable, individuals with one version of the trait must produce more offspring than those with a different version of the trait

Question 10

Variation for a Trait

Answer 10

Different versions of a trait are present within a population

Question 11

Heritability

Answer 11

The different versions of a trait may be passed from parents to offspring

Question 12

Differential Reproductive Success

Answer 12

Individuals with the version of a trait most suited to reproduction in their environment generally leave more offspring than individuals with other versions of the trait

Question 13

Sexual Selection

Answer 13

Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex

Question 14

Hardy-Weinberg Equilibrium

Answer 14

If the allele frequencies are known predictions can be made about the genotypes of the offspring that the population produces

Question 15

Fitness

Answer 15

A measure of the relative amount of reproduction of an individual with a particular phenotype compared with the reproductive output of individuals of the same species with alternative phenotype

Question 16

First Element of Fitness

Answer 16

An individuals fitness is measured relative to other genotypes or phenotypes in the population

Question 17

Second Element of Fitness

Answer 17

Fitness depends on the specific environment in which the organism lives

Question 18

Third Element of Fitness

Answer 18

Fitness depends on an organism’s reproductive success compared with other organisms in the population

Question 19

Adaptation

Answer 19

Refers both to the process by which organisms become better matched to their environment and to the specific features that make an organism more fit

Question 20

Artificial Selection

Answer 20

A special case of natural selection because the differential reproductive success is determined by humans rather than by nature

Question 21

Directional Selection

Answer 21

Individuals with one extreme of the range of variation in the population have higher fitness. Ex. Milk production

Question 22

Stabilizing Selection

Answer 22

Individuals with intermediate phenotypes are the most fit. Ex. Healthy baby weights are in the middle of the distribution

Question 23

Disruptive Selection

Answer 23

Individuals with extreme phenotypes have the highest fitness and those with intermediate phenotypes have the lowest fitness. Ex. Salmon reproduction

Question 24

Fossil

Answer 24

Hard parts of an organism that can be preserved for many years

Question 25

Radiometric Dating

Answer 25

Helps in telling an organisms evolutionary history by telling us the age of the rock where the fossil was found

Question 26

Fossil Record

Answer 26

Physical evidence of organisms that lived in the past

Question 27

Biogeography

Answer 27

Patterns in the geographic distribution of living organisms

Question 28

Comparative Anatomy and Embryology

Answer 28

Growth, development, and body structures of major groups of organisms

Question 29

Molecular Biology

Answer 29

Examination of life at the level of individual molecules

Question 30

Laboratory and Field Studies

Answer 30

Implementation of the scientific method to observe and study evolutionary mechanisms

Question 31

Homologous Structures

Answer 31

An organ or bone that appears in different animals suggesting there is a common ancestor between them

Question 32

Vestigial Structures

Answer 32

Homologous Structures sometimes have little or no function at all but they exist because they had value in the ancestor species