Bi201 Test 1

Front 1

Evolution

Back 1

Changes in the genetic characteristics of a population over time (esp. allele frequencies)

Front 2

Population

Back 2

group of individuals of the same species living in the same area at the same time

Front 3

Common ancestry

Back 3

Relates all species to a previous species

Front 4

Descent with Modification (Process)

Back 4

Characteristics of species are modified from generation to generation (Pattern)

Front 5

LUCA

Back 5

last universal common ancestor (Hypothetical species that all species trace their ancestry back to)

Front 6

Tree of Life

Back 6

family tree of organisms that describes genealogical relationships among species with a single ancestral species at its base

Front 7

Speciation

Back 7

natural selection causing populations of one species to diverge to form new species

Front 8

Phylogeny

Back 8

actual genealogical relationships among all organisms (ex: family, ancestors, etc.)

Front 9

3 Major domains

Back 9

Eukarya, Bacteria, Archaea

Front 10

Scientific Method

Back 10

Principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, collection of data through observation and experiment, and the formulation and testing of hypotheses

Front 11

Heritable traits

Back 11

Traits passed on to offspring

Front 12

Darwin's Four Postulates

Back 12

1. Variation exists
2. Certain traits are heritable
3. More offspring produced than can survive
4. Individuals with certain traits more likely to survive

Front 13

3 Requirements for Natural Selection to Operate

Back 13

1. Variability
2. Heritability
3. Differential Reproduction

Front 14

Cell Theory

Back 14

All organisms are made up of cells and all cells come from existing cells

Front 15

Theory (2 components?)

Back 15

Explanation for a very general class of phenomena or observations

Front 16

Darwin's Book

Back 16

On the Origin of Species by Means of Natural Selection

Front 17

Typological thinking

Back 17

Perfect and unchanging - fixed for all time

Front 18

Population Thinking

Back 18

Variation among individuals in a population key to understanding nature of species

Front 19

Transmutation

Back 19

Species changing over time

Front 20

Acquired Traits

Back 20

Acquired characteristics that could be passed off to offspring

Front 21

Strata

Back 21

Layers of rock sediment

Front 22

Natural Selection

Back 22

Process by which individuals with certain heritable traits tend to produce more surviving offspring than do individuals without those traits, often leading to a change in the genetic makeup of the population

Front 23

Homologous Structures

Back 23

different functions but are structurally similar because of common ancestry
(Ex: limbs vs. wings)

Front 24

Analogous structures

Back 24

similar function served and structurally similar due to convergent evolution, but not derived from a common ancestry
(Ex: birds and bats both fly but no common ancestor with that ability)

Front 25

Vestigial structures

Back 25

remnants of features that served important functions in an organism's ancestors

Front 26

transitional feature

Back 26

trait in a fossil species that is intermediate between those of older and younger species

Front 27

Comparative embryology (Developmental homology)

Back 27

comparisons of early stages of development among organisms

Front 28

Genetic homology

Back 28

comparisons of DNA sequences and genetic traits

Front 29

Structural homology

Back 29

Similarity in adult morphology

Front 30

Acclimation

Back 30

individual phenotype changes in response to environment (changes are not passed on)

Front 31

Adaptation

Back 31

allele frequencies in a population change in response to natural selection

Front 32

Darwinian Fitness

Back 32

an organism's ability to reproduce surviving offspring

Front 33

Genetic Variation

Back 33

# and relative frequency of alleles that are present in a particular population

Front 34

Gene pool

Back 34

total collection of genes in a population at any one time

Front 35

Four Mechanisms of Evolution that shift allele frequencies

Back 35

Natural selection, genetic drift, gene flow, mutations

Front 36

Directional selection

Back 36

pattern of natural selection that favors one extreme phenotype with the result that the average phenotype of a population changes in one direction. generally reduces overall genetic variation

Front 37

Disruptive Selection

Back 37

pattern of natural selection that favors extreme phenotypes at both ends of the range of phenotypic variation. Maintains overall genetic variation

Front 38

Purifying selection

Back 38

disadvantageous alleles decline in frequency

Front 39

"Fixed" Allele

Back 39

an allele that remains in the gene pool because all members are homozygous for that allele

Front 40

Stabilizing Selection

Back 40

Pattern of natural selection that favors phenotypes near the middle of the range of phenotypic variation. Reduces overall genetic variation.

Front 41

Heterozygote Advantage

Back 41

Higher fitness than homozygous, thus maintain genetic variation in the population

Front 42

Balancing selection

Back 42

A pattern of natural selection in which no single allele is favored in all populations of a species at all times. Balance among alleles in terms of fitness and frequency.

Front 43

Frequency-dependent selection

Back 43

A pattern of selection in which certain alleles are favored only when they are rare, form of balancing selection.
Genetic variation is maintained or increased

Front 44

Genetic Drift

Back 44

any change in allele frequencies in a population due to chance, random with respect to fitness

Front 45

Population bottleneck

Back 45

loss of genetic diversity when # of individuals is greatly reduced, causes genetic drift by limiting population size

Front 46

Founder effects

Back 46

few individuals colonize a new habitat
(Ex: Amish rate of polydactyly very high)

Front 47

Gene flow

Back 47

Movement of individuals from one population to another

Front 48

Mutation

Back 48

restores genetic diversity by creating new alleles, causes random changes in genes

Front 49

Deleterious alleles

Back 49

alleles that lower fitness

Front 50

Artificial Selection

Back 50

changes in populations occur when humans select which individuals will produce the most offspring

Front 51

Hardy-Weinberg model

Back 51

Assumes population will not change overtime, used to study actual populations

Front 52

Hardy-Weinberg Principle

Back 52

Principle of population genetics that states that genotype frequencies in a large population do not change from generation to generation in the absence of evolutionary processes

Front 53

5 conditions of a population remaining in equilibrium

Back 53

Large Population, No migration, No net mutations, Random mating, no natural selection

Front 54

P+q =

Back 54

1

Front 55

Frequency of AA genotype

Back 55

p^2

Front 56

Frequency of aa genotype

Back 56

q^2

Front 57

Frequency of Aa genotype

Back 57

2pq

Front 58

Inbreeding Depression

Back 58

decline in average fitness that takes place when homozygosity increases and heterozygosity decreases in a population

Front 59

Inbreeding

Back 59

Mating between two individuals that share a very close common ancestor - leads to loss of genotypes, NOT alleles

Front 60

Fundamental asymmetry of sex

Back 60

eggs expensive, sperm cheap (females invest more in their offspring than do males)

Front 61

Sexual Selection

Back 61

Type of natural selection that violates random mating, individuals differ in their ability to attract mates

Front 62

Mate Choice

Back 62

Females are choosy about their mates, AKA intersexual selection

Front 63

Sexual Dimorphism

Back 63

Sexual traits of males much more exaggerated than females as a result of intrasexual selection

Front 64

Intrasexual selection

Back 64

direct competition between members of the same sex for mates of the opposite sex

Front 65

Microevolution

Back 65

change in alleles over time, from one generation to the next

Front 66

Macroevolution

Back 66

creation of a new gene pool

Front 67

Speciation

Back 67

When one species splits into two or more species

Front 68

Species

Back 68

evolutionarily independent population or group of populations

Front 69

Biological species concept

Back 69

defines species as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring

Front 70

Reproductive isolation

Back 70

Prevents members of different species from mating with each other

Front 71

Prezygotic isolation

Back 71

individuals of different species are prevented from mating

Front 72

Postzygotic Isolation

Back 72

hybrid offspring has low fitness and does not survive or produce offspring

Front 73

Hybrid viability

Back 73

Ability for hybrid offspring to survive

Front 74

Hybdrid fertility

Back 74

Ability for hybrid offspring to be fertile

Front 75

Morphospecies concept

Back 75

identifies evolutionary independent lineages by differences in morphology

Front 76

Phylogenetic Species concept

Back 76

reconstructing the evolutionary history of populations with monophyletic groups

Front 77

Monophyletic group (clade)

Back 77

ancestral population plus all of its descendants and just its descendants

Front 78

Synapomorphies

Back 78

homologous traits inherited from a common ancestor that are unique to certain populations or lineages

Front 79

Phylogenic species

Back 79

Smalles identifiable group with synapomorphy

Front 80

Subspecies

Back 80

populations that live in discrete geographic areas and have their own identifying traits but are not distinct enough to be considered a separate species

Front 81

Allopatric speciation

Back 81

speciation that begins with physical isolation

Front 82

Dispersal

Back 82

Colonization of a new habitat and forming a new population

Front 83

Vicariance

Back 83

physical barrier splits a widespread population into subgroups that are physically isolated

Front 84

Sympatric speciation

Back 84

speciation occurring amongst populations that occupy the same location

Front 85

Polyploidiation

Back 85

genetic isolation is created by formation of polyploidy individuals that can only breed with eachother

Front 86

Autopolyploid (intraspecific)

Back 86

Formation of different # of chromosomes due to mutation

Front 87

Allopolyploid (interspecific)

Back 87

Formation of different # of chromosomes due to different species mating

Front 88

Fusion

Back 88

Erasing distinctions between two isolated populations caused by gene flow

Front 89

Reinforcement

Back 89

Natural selection for traits that isolate populations reproductively - leads to speciation

Front 90

Hybdridization

Back 90

Leads to extinction or possibly origination of a new species by mixing two independent populations

Front 91

Phylogeny

Back 91

evolutionary history of a group of organisms

Front 92

Branch

Back 92

population through time

Front 93

node

Back 93

point in time when an ancestral species split into two descendent species

Front 94

Tip (terminal node)

Back 94

a group that is living today or ended in extinction

Front 95

Phenetic estimation

Back 95

using computer modeling and statistics to summarize similarity among populations

Front 96

Cladistic estimation

Back 96

Using parsimony to summarize similarity among populations

Front 97

Parsimony

Back 97

A principle of logic stating that the most likely explanation or pattern is the one that implies the least amount of change

Front 98

Homology

Back 98

Traits are similar due to common ancestors

Front 99

Homoplasy

Back 99

traits are similar for reasons other than common ancestry

Front 100

Ancestral trait

Back 100

characteristic that existed in an ancestor

Front 101

Derived trait

Back 101

a characteristic that is a modified form of an ancestral trait that exists today (Ex: HOX genes)

Front 102

Outgroup

Back 102

species or group that is closely related to the monophyletic group but not part of it

Front 103

Adaptive radiation

Back 103

rapid speciation in a single lineage is followed by divergence into many different adaptive forms

Front 104

3 Hallmarks of adaptive radiation

Back 104

1. Monophyletic group 2. speciation is rapid 3. species diversify ecologically