Biology 126 Test One - Evolution And Diversity

Front 1

Population Thinking

Back 1

Ability to analyze trait frequencies, event probabilities, and other attributes of populations. Evolution relies on such thinking.

Front 2

Population

Back 2

All individuals of a certain species living in the same space at the same time.

Front 3

Descent with modification

Back 3

1-Species and their descendant species change through time.
2-Past species are ancestors of species living today. (Common ancestory)

Front 4

fossil record

Back 4

al lthe fossils that have been found and descri ed in scientific literature

Front 5

transitional feature

Back 5

An intermediate trait between younger and older species
-includes: transitional forms and vestigial traits

Front 6

law of succession

Back 6

extinct species are succeed in the same region by similar species

Front 7

vestigial trait

Back 7

feature with no or reduced function

Front 8

homology

Back 8

similarity inherited from common ancestors
Three types: genetic, developmental, and structural

Front 9

Darwin's four postulates

Back 9

1-need variation within population
2-Differences must be heritable
3-In each generation more offspring produced that can survive
4-Most fit individual produce offspring and hence the next generation (subset of individual that survive is nonrandom)

Front 10

fitness

Back 10

Ability of an individual to produce offspring relative to other individuals in the population.

Front 11

adaptation

Back 11

is a heritable trait that increases the fitness of the individual relative to their environment

Front 12

Evolution Myth 1
Lamarckian Inheritance

Back 12

Doesn't occure- Only population change over time

Front 13

Evolution myth 2
Acclimation

Back 13

If phenotype change and not the genotype it isn't evolution

Front 14

Evol myth 3
Goals

Back 14

Evolution isn't goal oriented; favors individual that occur by chance alone

Front 15

Evol myth 4
Progessive

Back 15

Evol isn't progressive; not aim to produce more complicated organisms

Front 16

Evol myth 5
better organism

Back 16

no 'higher' or 'lower' organisms

Front 17

genetic correlation

Back 17

caused by pleiotropy - a single allele affects multiple traits. Causes fitness trade offs

Front 18

fitness trade-off

Back 18

a compromise between two traits. Due to pleiotropy or competing goals.

Front 19

gene pool

Back 19

all the gametes in a certain generation in a population.

Front 20

Hardy-Weinberg principle

Back 20

p + q = 1

p^2 + 2pq + q^2 = 1

Front 21

Hardy-Weinberg assumptions

Back 21

1-no natural selection at gene in question
2-no genetic drift
3-no gene flow
4-no mutation
5-random mating

Front 22

directional selection

Back 22

pressure causes average phenotype to move in one direction
-genetic variety decreases and trait mean moves in one direction

Front 23

disruptive selection

Back 23

pressure on the mean trait and extreme values favored -mean and genetic variety maintained

Front 24

stabilizing selection

Back 24

Pressure on the extremes. -genetic variety decreases, but mean stays the same

Front 25

purifying selection

Back 25

disadvantageous alleles decrease in frequency

Front 26

Balancing selection

Back 26

no allele has an advantage so they stay the same frequency over time

Front 27

heterozygote advantage

Back 27

heterozygous allele are more fit. a type of balancing selection

Front 28

frequency-dependent selection

Back 28

Common alleles get eliminated, a type of balancing selection

Front 29

Genetic Drift

Back 29

Change in allele frequency due to chance, aka random in respect to fitness. Affects small population more, because it is simply a sampling error.

Front 30

founder effect

Back 30

Change in allele frequency when a new population is established from a few individuals due to sampling error. Type of genetic drift.

Front 31

genetic bottleneck

Back 31

Reduction in allelic diversity due to a sudden random reduction in population size (ie extinction). Type of genetic drift.

Front 32

gene flow

Back 32

Movement of alleles between populations.

Front 33

deleterious allele

Back 33

allele that lowers fitness.

Front 34

mutation

Back 34

Any change in the hereditary information of an organism.

Front 35

inbreeding

Back 35

Inbreeding between closely related individuals. Increases homozygosity.

Front 36

inbreeding depression

Back 36

Reduced fitness of a population when deleterious recessive alleles start occurring homozygotic more often due to inbreeding.

Front 37

sexual selection

Back 37

Natural selection that favors the individuals that can get mates
-male vs male compete for right to territory or some other way to mate with females
-female choice: males get flashy feather to attract females.

Front 38

sexual dimorphism

Back 38

Any trait that differs between males and females.

Front 39

speciation

Back 39

The evolution of two or more distinct species from a single common ancestor.

Front 40

biological species concept

Back 40

Species are identified by reproductive isolation. No gene flow between populations. Could be they cannot inbreed or they cannot produce viable or fertile offspring

Front 41

perzygotic isolation

Back 41

gene flow prevented because different species cannot mate
-temporal
-habitat
-behavioral
-gametic barrier
-mechanical

Front 42

postzygotic isolation

Back 42

gene flow is prevented because hybrid offspring are infertile or not viable and die.

Front 43

morphospecies concept

Back 43

Species identified by size, shape, and other morphological features.

Front 44

cryptic species

Back 44

Species differ in traits other than morphology

Front 45

phylogenetic species concept

Back 45

smallest monophyletic group on the phylogenetic tree

Front 46

monophyletic group / clade

Back 46

An evolutionary unit that includes an ancestral population and all of its descendants but no others.

Front 47

synapomorphy

Back 47

A shared, derived trait found in two or more taxa that is present in their common ancestor, but missing in more distant ancestors.

Front 48

subspecies

Back 48

A populations that has distinctive traits and some genetic differences relative to other populations of the same species but is not distinct enough to be classified as a separate species.

Front 49

allopatric speciation

Back 49

Divergence of populations into different species by physical isolation of populations in different geographic areas.

Front 50

vicariance

Back 50

physical splitting apart of a population into smaller ones by geographic isolation.

Front 51

allopatry

Back 51

Condition in which two or more populations live in different geographic areas.

Front 52

biogeography

Back 52

Study of how species and populations are distributed geographically.

Front 53

sister species

Back 53

Closely related species which occupy adjacent branches of a phylogenetic tree.

Front 54

sympatric speciation

Back 54

Divergence of species living in the same geographical area.

Front 55

polyploidy

Back 55

Having more than two sets of full chromosomes.

Front 56

Autopolyploid

Back 56

State of having more than two full sets of chromosomes due to a mutation that doubled the chromosome number.

Front 57

Allopolyploid

Back 57

Gaining duplicate number of chromosomes from hybridization.

Front 58

reinforcement

Back 58

Natural selection for traits that prevent inbreeding between recently diverged species.

Front 59

hybrid zone

Back 59

A geographic area between two species, sometimes with fertile hybrid offspring.

Front 60

branch of a tree

Back 60

represents a population through time

Front 61

node

Back 61

point where an ancestral species split into two or more descendant species

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tip

Back 62

represents a extant or extinct group or species

Front 63

phenetic approach

Back 63

A method for constructing a phylogenetic tree by computing a statistic that summarizes the overall similarity among populations, based on the available data

Front 64

cladistic approach

Back 64

Constructing phylogenetic trees based on identifying unique traits of each monophyletic groups.

Front 65

homoplasy

Back 65

Similar traits due to convergent evolutions.

Front 66

convergent evolution

Back 66

Independent evolution of analogous traits because different organisms are adapting to similar environments.

Front 67

outgroup

Back 67

Taxon that is closely related to a particular monophyletic group but not related to it.

Front 68

4 types fossils

Back 68

-Intact
-Compression
-Cast Fossil
-Permineralized fossil

Front 69

Adaptive radiation

Back 69

Rapid evolutionary diversification from one lineage.

Front 70

Cambrian Explosion

Back 70

Rapid diversification of animal body types around 543mya.

Front 71

Evidence for Evolution

Back 71

1-resemblance of modern to fossil forms
2-transitional features
3-fact of extinction
4-vestigial traits
5-change in contemporary populations
6-proximity of related species
7-structural, developmental, and genetic homologies
8-contemporary formation of new species

Front 72

adaptation

Back 72

genetically based trait that increases and individuals ability to produce offspring in a particular environment

Front 73

Constraints on adaptation

Back 73

1-trade-offs
2-genetic
3-historical