Unit 7 Natural Selection and Evolution

Question 1

What is the evidence for evolution

Answer 1

Fossil Record, Homologous Structures (divergent evolution), Vestigial Structures, Comparative Anatomy, Comparative Embryology, Molecular Biology, Biogeography

Question 2

What is the smallest unit that can evolve?

Answer 2

Population

Question 3

Microevolution

Answer 3

Is the small changes in allele frequencies in a population over generations.
Consists of adaptations that evolve within a population, confined to one gene pool

Question 4

Macroevolution

Answer 4

Evolution above the level of species. Formation of new species etc.

Question 5

Three mechanisms that cause changes in allele frequencies

Answer 5

Natural selection, genetic drift, and gene flow

Question 6

Genetic Varability (Average Heterozygosity)

Answer 6

Measures the average percent of loci that are heterozygous in a population

Question 7

What results in the formation of new alleles

Answer 7

Mutations
*However point mutations in non coding regions (introns) generally result in neutral variation conferring no selective advantage

Question 8

What can be use to test whether a population is evolving

Answer 8

Hardy Weinberg equation (p^2 + 2pq + q^2)

Question 9

Gene pool

Answer 9

Consists of all the alleles for genes of all the loci in a population

Question 10

5 conditions that must be met in order for a population to be considered in hardy weinberg equilibrium

Answer 10

1. No gene flow
2. No natural selection
3. No mutation
4. Random mating
5. Large population size

Question 11

Only mechanism that consistently causes adaptive evolution

Answer 11

Natural Selection

Question 12

Genetic Drift

Answer 12

Describes how allele frequencies fluctuate unpredictably from one generation to the next. Genetic drift results in decreased genetic variation and has a more significant effect on smaller populations

Question 13

Two types of genetic drift

Answer 13

Bottleneck Effect and Founder Effect

Question 14

Gene Flow

Answer 14

Movement of alleles among populations. Can be beneficial or harmful. Gene flow can REDUCE difference between populations over time

Question 15

Relative Fitness

Answer 15

The contribution an individual makes to the gene pool of the next generation relative to other individuals

Question 16

Types of Selection

Answer 16

1. Directional Selection
2. Disruptive selection
3. Stabalizing Selection

Question 17

Directional Selection

Answer 17

Directional selection favors a SINGLE phenotype or a SINGLE allele in the population.

Question 18

Adaptive Evolution

Answer 18

Occurs as the degree to which a species is well suited for life in its environment

Question 19

Sexual Selection
Intrasexual selection: Direction competition for mates (usually males)
Intersexual Selection: Mates Choice (usually females)

Answer 19

Process by which individuals with certain inherited characteristics are more likley to acquire mates than others

Question 20

What does natural selection act on

Answer 20

AN ORGANISMS PHENOTYPE

Question 21

Balancing Selection

Answer 21

Refers to forms of natural selection by which multiple alleles are actively maintained in a gene pool of the population

Question 22

Two types of Balancing selection

Answer 22

1. Frequency Dependent Selection

2. Heterozygote advantage

Question 23

Biological Species Concept

Answer 23

States that two organisms are species if they can mate and produce healthy, fertile offspring

Question 24

Reproductive Isolation

Answer 24

Is the existence of biological factors that impede two species from producing fertile offspring

Question 25

Prezygotic Barriers

Answer 25

1. Habitat Isolation 2. Temporal Isolation 3. Behavioral Isolation 4. Mechanical Isolation 5. Gametic isolation

Question 26

Postzygotic Barriers

Answer 26

1. Reduced Hybrid Viability 2. Reduced Hybrid Fertility 3. Hybrid Breakdown

Question 27

First thing that is necessary in order for speciation to occur

Answer 27

Gene flow must be interrupted between two populations, reproductively isolating them

Question 28

Other definitions of Species

Answer 28

1. Morphological Species Concept 2. Ecological Species Concept 3. Phylogenetic Species Concept

Question 29

Allopatric Speciation

Answer 29

Geographic Separation of population form parent species

Question 30

Sympatric Speciation

Answer 30

New species rise within the parent population

Question 31

How gene flow can be reduced in order for sympatric speciation to occur

Answer 31

1. Polyploidy (more common in plants) 2. Habitat Differentiation 3. Sexual Selection (ake Victoria Chichlids)

Question 32

How fast does speciation can occur

Answer 32

Speciation can occur in just one generation (polyploidy) or it can take a very long time. It all depends on the environment and chance

Question 33

Gradual Speciation

Answer 33

Species form gradually over time

Question 34

Punctuated Equilibrium

Answer 34

Species appear suddenly, persist essentially unchanged for a long period of time, the apparently disappear.

Question 35

What resulted from the break up of Pangea

Answer 35

The Permian Extinction

Question 36

Oldest prokaryotes fossils

Answer 36

Stromatlies

Question 37

Correct Order of Life Appearing on Earthd

Answer 37

1. First prokaryotes appeared on earth 2. Formation of atmospheric oxygen 3. Single-celled eukaryotes 4. Multicelled eukaryotes 5. Aniamals 6. Colonization of Land

Question 38

Heterochrony

Answer 38

Evolutionary change in the rate or timing of developmental events

Question 39

Homeotic Genes

Answer 39

Determine where basic features will develop

Question 40

Hox Genes

Answer 40

Class of homeotic genes that provide positional information during embryonic development

Question 41

Phylogeny

Answer 41

Is the evolutionary history of a species or group of related species

Question 42

Taxonomy

Answer 42

The ordered division and Naming or organisms

Question 43

Branch point

Answer 43

Represents divergence of two species

Question 44

Sister Taxa

Answer 44

Groups that share an immediate common ancestory

Question 45

Rooted Tree

Answer 45

Includes a branch to represent the last common ancestor of all the taxa in the tree

Question 46

Clade

Answer 46

A group of species that includes an ancestral species and all of its descendants All Clades are MONOPHYLETIC

Question 47

Paraphyletic Grouping

Answer 47

Consists of an ancestral species and some, but not all of its descendants