Organismal Biology 1306 Exam 1

Front 1

Evolution

Back 1

Change in genetic composition of populations over time.

Individuals do not evolve, populations do

Front 2

Evolutionary Theory

Back 2

-Understanding and application of the processes of evolutionary change to biological problems

-Allows us to make predictions about biological world

Front 3

Darwins explanatory theory for evolution

Back 3

-Species change over time

-Share a common ancestor (descent w/modification)

-Natural Selection

Front 4

Natural Selection

Acts on what?

Back 4

Mechanism that produces change.

-Acts on mutation and results in adaptation

Front 5

Mutations

Back 5

-Origin of genetic variation

-Change in nucleotide sequences

-Randomly

Front 6

Alleles

Back 6

Different forms of a gene

Front 7

Gene pool

Back 7

Sum of all copies of all alleles at all loci in a population

Front 8

Allele frequency

Back 8

Proportion of each allele in the gene pool

Front 9

Genotype Frequency

Back 9

Proportion of each genotype among individuals in the population

Front 10

Adaptation

Back 10

-Favored trait that evolves through natural selection

-Produces trait

Front 11

Gene flow

Back 11

-Migration of individuals or movement of gametes between populations which can change allele frequencies

-Migration

Front 12

Genetic Drift

Back 12

-Random changes in allele frequencies from one generation to the next

-Mostly in small populations

-Accidents, only lucky genes

-Does not promote adaptation

Front 13

Mechanisms of Evolution

Back 13

Mutations, gene flow, genetic drift, and natural selection

Front 14

Population Bottleneck

Back 14

-Environmental result in survival of only a few individuals due to environmental issues, hunting

-Result in genetic drift

-Loose much of genetic variation

-Bad for endangered species and small populations

Front 15

Founder Effect

Back 15

Genetic drift changes allele frequencies when a few individuals colonize a new area

Front 16

Sexual Selection

Back 16

-Individuals mate with particular opposite sex rather than random

-Trade-off between attracting mates and predators

EX: Long tails in birds

Front 17

Genetic Structure

Back 17

Frequency of different alleles and genotypes in a population

Front 18

Hardy-Weinberg Equilibrium

Back 18

Model where allele frequencies dont change across generations; genotype can be predicted from allele frequencies

-Random mating and infinite population size

-No mutations, no gene flow, selection of genotyoes

Front 19

Qualitative Trait

Back 19

Influences by alleles at one locus, black versus white

Front 20

Quantitative Traits

Back 20

Influenced by alleles at more than one locus, continuous variation, body size

Front 21

Stabilizing Selection

Back 21

Favor average individuals, reduces variation but no change in mean, also purifying selection

-Gets narrower towards middle

Front 22

Directional selection

Back 22

Favors one direction from mean

-Moves to one side

Front 23

Disruptive selection

Back 23

Favors in both directions, increased variation

-M shaped graph

Front 24

Purifying slection

Back 24

Selection vs. any deleterious mutations to usual gene sequence

Front 25

Nucleotide substitution

Back 25

Change in one nucleotide in a DNA sequence

Front 26

Synonymous Substitution

Back 26

Silent, doesn't change encoded amino acid

Front 27

Nonsynonymous substitution

Back 27

Missense, deleterious but be neutral or advantageous

Front 28

Pseudogenes

Back 28

Copies of genes that are no longer functional

Front 29

Insertions, deletions, rearrangements of DNA sequences

Back 29

Types of mutations, larger effect than point mutations, can change reading frame of protein coding sequences

Front 30

Neutral Theory

Back 30

@ molecular level, majority of variants are neutral, accumulate through genetic drift rather than positive selection

Front 31

Sexual Reproduction

Back 31

Results in new gene combinations and produces genetic variety

Facilitates rape of damaged DNA

Front 32

Asexual Reproduction

Back 32

Deleterious mutations accumulate, Mullers ratchet

Front 33

Lateral Gene Transfer

Back 33

Individual genes, organelles or genome fragments move horizontally from lineage to another.

-DNA picked up from environment, or transferred in a viral genome

-Increases genetic variation

-Uncommon in eukaryotes

Front 34

Gene duplication

Back 34

Genomes gain new functions

Front 35

Gene duplication fates

Back 35

-Both may retain original function

-Diverge in diff. tissues or at different times in development

-One copy may accumulate deleterious mutations and become functionless pseudogene

-One copy original function, other changes

Front 36

In Vitro Evolution

Back 36

New molecules are produces in the lab to perform novel functions

Front 37

Species

Back 37

Organisms that mate with one another

Front 38

Speciation

Back 38

Divergence of biological lineages and emergence of reproductive isolation b/w lineages

Front 39

Cryptic Speciaes

Back 39

Two or more species that are morphologically indistinguishable but don't interbreed

Front 40

Reproductive isolation

Back 40

two groups of organisms can no longer exchange genes

Front 41

Allopatric Speciation

Back 41

Separated by physical or geographic barrier such as sea levels rising, continents drifting, climates change

-Sister species, species that are e/others closest relatives but live opposite sides

Front 42

Sympatric speciation

Back 42

Speciation w/o physical isolation

Front 43

Disruptive speciation

Back 43

Indiv. w/ certain genotypes prefer distinct microhabitats where mating takes place

Front 44

Polyploidy

Back 44

Duplication of sets of chromosomes within individuals

-Common in plants because many can self-fertilize

Front 45

Autopolyploidy

Back 45

Chromosome duplication in single species

Front 46

Allopolyploidy

Back 46

combining chromosomes of two different species

Front 47

Prezygotic isolation mechanisms

Back 47

prevent hybridization

Front 48

Postzygotic isolation mechanisms

Back 48

Reduce fitness of hybrids, reinforcement of prezygotic mechanisms

-Low hybrid zygote/adult viability

-Hybrid infertility

Front 49

Mechanical Isolation

Back 49

Differences in sizes and shapes of reproductive organs

Front 50

Temporal isolation

Back 50

Species breed at different times of year or day

Front 51

Behavioral isolation

Back 51

Individuals fail to recognize mating behaviors of other species

Front 52

Habitat isolation

Back 52

Two close species evolve preferences for living or mating in diff. habitats

Front 53

Gametic isolation

Back 53

sperm and eggs of diff species will not fuse

Front 54

Hybrid zones

Back 54

when reproductive isolation is incomplete, narrow b/c of pressure against hybrids