Ecology Test #1

Front 1

evolution

Back 1

species change over time

Front 2

Lamarkian evolution

Back 2

species change over time, based on the great changed of being--less complex organisms start at the base of the chain and evolve up the chain over time

Front 3

population

Back 3

consists of individuals of the same species that are living in the same area at the same time

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Darwin and Wallace

Back 4

evolution occurs because traits vary among individuals in a population and because individuals with certain traits leave more offspring than others do

Front 5

two predictions of natural selection

Back 5

-Species change through time; -species are related by common ancestry

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fossil

Back 6

any trace of an organism that lived in the past

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extant species

Back 7

Species living today

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vestigial trait

Back 8

a reduced or incompletely developed structure that has no function, or reduced function, but is clearly similar to functioning organs or structures in closely related species

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homology

Back 9

a similarity that exists in species because they inherited the trait from a common ancestor

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Genetic homology

Back 10

occurs in DNA, RNA, and amino acid sequences

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Developmental homology

Back 11

recognized in embryos--many embryos look similar when developing--some mammals have gill pouches

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Structural homology

Back 12

Similarity in adult morphology/form

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Three levels of homology

Back 13

genetic, structural, developmental

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artificial selection

Back 14

When a human chooses certain individuals with desirable traits to reproduce

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Darwin's four postulates of natural selection

Back 15

1)individual organisms in a pop. vary in traits

2) some of the trait differences are heritable

3)Only some individuals in the pop. survive long enough to produce offspring, some will produce more than others

4)Individuals with certain heritable traits are more likely to survive and reproduce

Front 16

Natural selection

Back 16

Occurs when individuals with certain characteristics produce more offspring than do individuals without those characteristics

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fitness

Back 17

the ability of an individual to produce surviving ,fertile offspring relative to that ability in other individuals in a pop

Front 18

adapation

Back 18

a heritable trait that increases the fitness of an individual in a particular environment relative to individuals lacking that trait

Front 19

Hardy-Weinberg Principle

Back 19

mathematical null hypothesis for the study of evolutionary process.

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Claims of hardy weinberg

Back 20

Allele frequencies: p +q = 1

Genotype frequences: p2 + 2pq + q2 =1

When alleles are transmittedvia meiosis and random combinations of gametes, frequencies do not change over time

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Assumptions of hardy weinberg

Back 21

-Random mating, -no natural selection (all members of of parental generation survived and contributed equally to gene pool) -no genetic drift (selection of population represents actual population) -no gene flow (no immigration or emigration) -no mutation

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Speciation

Back 22

a splitting event that creates two or more distinct species from a single ancestral speices. Results from genetic isolation and genetic divergence

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Genetic isolation

Back 23

results from lack of gene flow

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Genetic Divergence

Back 24

occurs because selection, genetic drift, and mutation proceed independently in the isolated populations

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Biological species concept

Back 25

Defines species as a population in genetic isolation

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Prezygotic isolation

Back 26

prevents individuals of different species from mating

Front 27

Postzygotic isolation

Back 27

offspring of matings between members of different species do not survive or reporduce

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Disadvantages of biological species concept

Back 28

Cannot be evalutated in fossils or species that reproduce asexually. Difficult to apply when closely related populations do not overlap geographically

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Morphospecies concept

Back 29

species are defined by evolutionarily independent lineages by differences in size, shape, or other morphological features.

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Advantages of morphospecies concept

Back 30

widely applicable, useful when biologists have no data on extent of gene flow, equally applicable to sexual, asexual, or fossil species.

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Disadvantages of morphospecies concept

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may lead to naming of two or more species when there is only one polymorphic species, it cannot identify cryptic species, morphological features are subjective

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polymorphic species

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a species with differing phenotypes

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cryptic species

Back 33

a species that differs in traits other than morphology

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phylogenetic species concept

Back 34

identifies species based on the evolutionary history of species

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monopyletic group

Back 35

consists of an ancestral population, all of its descendants and only those descendants.

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Synapomorphy

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a trait that is found in certain groups of organisms and their common ancestor, but is missing in more ancient ancestors

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advantages of phylogenetic species concept

Back 37

it can be applied to any population and it is logical because different species have different synapomorphies only if they are isolated from gene flow and have evolved independently

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disadvantages of phylogenetic species concept

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phyolgenetic trees are only available for a tiny subset of populations

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allopatry

Back 39

when populations are geographically separated

Front 40

allopatric speciation

Back 40

when speciation begins with geographic isolation

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vicariance

Back 41

the physical splitting of a habitat

Front 42

two ways geographic isolation occurs

Back 42

dispersal or vicariance

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sympatry

Back 43

when populations live in the same geographic area or close enough to make interbreeding possible

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sympatric speciation

Back 44

speciation that occurs though populations live within the same geographical area

Front 45

2 events that initiate sympatric speciation

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external events, such as disruptive selection for extreme phenotypes, and internal events such as chromosomal mutations

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niche

Back 46

the range of ecological resources that a species can use and the range of conditions it can tolerate

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polyploidization

Back 47

when an error in meiosis or mitosis results in a doubling of the chromosome number

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autopolyploid

Back 48

produced when a mutation results in a doubling of chromosome number and the chormosomes all come from the same species

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allopolyploid

Back 49

created when parents that belong to different species mate and produce and offspring with two different sets of chromosomes

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hybrid zone

Back 50

a geographic area where interbreeding occurs and hybrid offspring are common