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Biol 214: Genes, Ecology, and Evolution > Exam 3 > Flashcards

Exam 3 Flashcards

1
Q

community structure

A

includes attributes like
1) # of species
2) species diversity
3) relative species abundance

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2
Q

guild

A

group of organisms that all make their living in the same way
ex: all seed-eating animals in an area

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3
Q

what is species richness and the problem with it?

A

.# of species in a community
problem: # of species depends on sample size

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4
Q

rarefraction???

A

can correct the over/undersampling of species richness

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5
Q

diversity

A

-measured with richness (# of species)
-evenness- how equal are the species in terms of abundance?
-Simpson’s index

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6
Q

Simpson’s Index

A

probability that any 2 individuals randomly chosen from community come from same species

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7
Q

Simpson’s Index of Diversity

A

probability that any 2 individuals chosen randomly from community come from different species

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8
Q

Simpson’s Reciprocal Index

A

number of equally common spcies you would need to measure the mix

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9
Q

food chains

A

simple interactions

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10
Q

food webs and the 2 types of interactions

A

summarize feeding relations in a community
-all food chains in an ecosystem
-help identify strong interactions
directly: predation, herbivory, parasitism
after food item is dead: detritivore

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11
Q

non-food web interactions

A

habitat formation, competition, amensalism, commensalism

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12
Q

indirect interactions

A

one species affects another through a third intermediate species
1) indirect commensalism
2) apparent competition

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13
Q

keytone species

A

-have disproportionate effect on their environment relative to abundance
-ecosystem may experience a dramatic shift if a keytone species is removed (even if small biomass or productivity)

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14
Q

green world hypothesis

A

predators play a role in maintaining plants in an ecosystem by limiting number of herbivores in that system

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15
Q

5 keystone interactions

A

1) competition
2)predation or herbivory
3) may be prey or predators
4) structure
5) may be dominant species but not always

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16
Q

where does species diversity tend to be higher?

A

-in complex environments
-intermediate levels of disturbance (high diversity) —–> allows some species to colonize but not enough time for competitive exclusion

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17
Q

equilibrium model of island biography

A

the theory of island biography by MacArthur and Wilson
-# of species on islands is determined by balance b/w species immigraiton and extinction
-rate of immigration of new species decreases as # of species increases
-rate of species extinction increases as # of species increases

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18
Q

when is immigration highest according to Equilirbium Model of Island Biogeography

A

new island with no organisms

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19
Q

why does extinction rate increase due to competition?

A

-population of each species decreases, creating larger pool of species for potential extinction

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20
Q

what is extinction on islands determined by?

A

size (allocation of space)

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21
Q

what is immigration on islands determined by?

A

isolation from source of immigrants

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22
Q

what are the 2 predictions of Model of Island Geography?

A

1) more species on large islands and near islands
2) species on islands is dynamic (always changing) but # remains the same

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23
Q

species turnover

A

the change as a result of immigration and extinction

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24
Q

4 updates from recent studies in regards to the Model of Island Geography?

A

1) species richness is not always at equilibrium
2) island size may affect immigration
3) island distance from source colonizers may affect extinction
4) area and isolation only 2 environmental factors. Other factors may affect richness

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25
Q

5 possible reasons why species richness increases in the tropics

A

1) time since perturbation (evolutionary hypothesis)
2) productivity
3) environmental heterogeneity (intermediate disturbance)
4) favorable (ambient) energy
5) interspecific interactions

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26
Q

geographical area hypothesis

A

strong positive relationship between area and species diversity

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27
Q

why is extinction rate lower in N.A and Asia during glaciation?

A

because had more diversity —-> more species available

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28
Q

natural selection

A

-differential reproductive success
-a trait that increases ability of individual to survive and reproduce compared to others that differ in that trait
-a trait that has risen via selection

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29
Q

evolution

A

-change in allele frequency in a population over time
-descent with modification

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30
Q

aristotle

A

-“ladder of nature”
-Scala naturae
-suggested that each entity had its perfect representation and had a perfect purpose in the order of life

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31
Q

Linnaeus

A

-father of taxonomy –> hierarchy of life
-binomial naming –> Genus species
-created ordered nested class classification system (based on common traits of reproduction)

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32
Q

James Hutton

A

-geologist, proposed idea of gradualism
-world runs through cycles of decay and repair
-major geological changes could be explained by accumulation of small processes caused by continuous processes (think rock cycle)

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33
Q

Charles Lyell

A

-father of modern geology
-used uniformitarianism to expand Hutton’s ideas
-same geological processes in past as today
-same rate as today (renewals, cycles)

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34
Q

Jean Baptiste de Lamarck

A

-linked evolution to adaptation
-extinct species have been replaced by descendants with new features
-said features (adaptations) helped them survive in their environment
-“inheritance of acquired characteristics”
-similar to “use/disuse” or “use or lose”
-Darwin rejected these ideas (good_

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35
Q

August Weismann

A

disproved Lamarck’s ideas by cutting tails of mice off

36
Q

Charles Darwin + Alfred Wallace

A

evolutionary history and mechanism of natural selection (old)

37
Q

Summary of 3 observations from Darwin

A

1) All species produce more offspring than needed to replace them
2) most populations remain fairly stable in size (once they get to K)
3) environmental resources for life are limited

38
Q

Inferences of Darwin’s observations

A

1) differential reproductive success (those w “best” traits survive and reproduce more)
2) those heritable, favorable traits (adaptations) accumulate over time, matching the species to its environment —> new species

39
Q

what has to be true for evolution via natural selection

A

1) phenotypic variation - individuals within populations are a variable
2) variation is in part heritable
3) competition - some individuals are more successful at surviving and reproducing
4) fitness is not random (linked to the phenotypic traits that vary among individuals)

40
Q

what does H^2 measure?

A

heritability- the proportion of total phenotypic variation due to gene variation

H^2= 0. no genetic differences. all env
H^2= 1 all differences are genetic. no env

41
Q

natural selection acts on _________ but evolution consists of changes in _________

A

phenotypes
allele frequencies

42
Q

evolution is always a generation _____ any changes in the environment

A

behind

43
Q

exaptations

A

traits that originally evolved for one function may continue to evolve and acquire new function

44
Q

is genetic material static?

A

no

45
Q

natural selection is ____ but ______

A

nonrandom but not progressive

no “advanced forms” just “better” at adapting

46
Q

why does natural selection act on individuals?

A

for good of population

altruism

47
Q

2 things missing from darwin’s theory

A

didnt know how variation was
1) generated in populations (mutations)
2) passed on to offspring (Mendel genetics)

48
Q

evidence of change through time in lineages

A

microevolution- changes in allele frequencies (thus distributions) within populations. can be seen within our lifetime
macroevolutions- large evolutionary change (typically differences among populations that would warrant species status)

49
Q

what reveals common ancestry?

A

homologous structures

50
Q

vestigial structures

A

-a rudimentary version of a body part that DOESNT WORK the way it once did
-fossil record and transitional forms (shows gradual change)

ex: archaeopteryx b/w dinosaurs and birds

51
Q

homologous structures

A

-structures adapted to different purposes b/c of descent w modification from common ancestor
-DNA, RNA or protein sequences can be homologous
-anatomically similar. functionally different

52
Q

what can sequence homology result from?

A

1) horizontal gene transfer –> “xenologs”
2) speciation event –> “orthologs” –> look for common descent (compare 2 different species)
3) duplicating event –> “paralogs” –> same organism. multiple copies of same gene (not good for assessing evolutionary differences between species. how 1 species changes over time)

53
Q

analogous structures

A

-“homoplasty”
-obtained by need
-anatomically different

54
Q

Divergent evolution

A

-homologus structures
-structures derived from common ancestor
-used to build phylogenetic trees

55
Q

Divergent evolution

A

-homologous structures
-structures derived from common ancestor
-used to build phylogenetic trees

56
Q

convergent evolution

A

-analogous structures
-functionally similar. anatomically different
-distinct phenotypes converged on same phenotype
-NEED BASED

57
Q

systematics

A

the study of biological diversity and its evolution

58
Q

taxonomy def and goal

A

the science of biological classification, how organisms are assigned to taxa/ groups
-goal: utility and monophyly

59
Q

nomenclature def and goal

A

-process by which taxa are named
-goal: stability

60
Q

systematics rules

A

1) taxa are arranged in hierarchical ranks
2) names are treated as if Latin regardless of origin
3) species names are binomials ex: Solanum tuberosum L.

61
Q

phylogenetics

A

study of evolutionary history and relationships among individuals/ groups of organisms

62
Q

what does the length of branch represent in phylogenetics?

A

time that taxa has been evolving

63
Q

terminal

A

a species

64
Q

branches

A

lines in a phylogenetic tree that connect nodes –> node
terminal –> node

65
Q

nodes

A

where branches intersect (represent ancestors)

66
Q

MRCA

A

most recent common ancestors
-nodes of terminals

67
Q

clade

A

a group of organisms believed to have evolved from a common ancestor

68
Q

root

A

MRCA of the ingroup (point that connects ingorup and outgroup)

69
Q

character

A

a feature common (homologous) to al terminals sampled

70
Q

character state

A

what a character looks like in an individual

71
Q

polytomy

A

more than 2 lineages diverged and dont know how

71
Q

polytomy

A

more than 2 lineages diverged and dont know how

72
Q

sister taxa

A

indicates lineages that share a branch point

73
Q

basal taxon

A

oldest species, most ancestral

74
Q

branch point

A

indicates where 2 lineages diverged

75
Q

monophyletic groups

A

contain all descendants of a MRCA

!!!! goal!!!!

76
Q

polyphyletic groups

A

exclude MRCA of its members
-not good
-inferred relationships

77
Q

paraphyletic groups

A

exclude descendants

78
Q

apomorphy

A

derived character unique to a clade

79
Q

synapomorphy

A

-an apomorphy SHARED by 2 or more taxa
-(homologous traits from common ancestor)
-most important trait when creating a tree

80
Q

autapomorphy

A

characters UNIQUE to a single TAXON and are uninformative for assessing relationships

81
Q

plesiomorphy

A

ancestral evolutionary trait homologous within clade but not required to that group

82
Q

symplesiomorphy

A

plesiomorphy shared by 2 or more taxa found in earliest common ancestor

83
Q

what is homoplastly?

A

-similarity in traits NOT due to common descent. OUT OF NECESSITY

84
Q

what causes homoplastly?

A

1) convergent evolution
2) parallel evolution- implies that same phenotype evolved in 2 separate lines from same ancestral phenotype
3) evolutionary reversals- the return of a derived character state to ancestral character state A-> T -> A

85
Q

phenotypic plasticity

A

capacity of 1 genotype to exhibit different phenotypes in different environments

-mechanism of environmeorthologntal variation

Biol 214: Genes, Ecology, and Evolution (5 decks)

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