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BIS 2B > final > Flashcards

final Flashcards

1
Q

allopatric speciation - vicariance

A

caused by geographical separation

  • ex: oxbow lake formation
  • tectonic plates & penguins
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2
Q

allopatric speciation - founder effect

A

a small subset of indiv separates from original pop & branches into new species

  • ex: european starlings
  • snails w/ opposite handedness
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3
Q

parapatric speciation

A

gradient leads to speciation
* birds around tibetan plateau

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4
Q

sympatric speciation

A

separate areas of same habitat
* sickleback fish
* hawthorn/apple inesects
* stick bugs on adjacent bushes

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5
Q

What is polyploidy? How does it influence reproductive isolation and speciation?

A

polyploidy is having multiple sets of DNA, which arise from non-disjunction ➞ when indiv mate they produce offspring with odd numbers of chrom who are inviable or infertile

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6
Q

evolutionary radiation

A

when rapid speciation results in a burst of new species from a single lineage

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7
Q

adaptive radiation

A

burst of speciation occurs b/c a group of species adapts to new ecological niches
* european finch colonized hawaii & adapted beaks based on their island specific envir
* California tarweed able to adapt to abiotic niches: elevation & precipitation ➞ unfilled space w/ little competition

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8
Q

relative neighbor effect

A

difference in interactions with neighboring species from low to high elevation
* benefits at ↑ elevation ➞ protection from wind, snow burial, cold sun, UV

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9
Q

intermediate disturbance hypothesis (IDH)

A

species diversity is highest at intermediate levels of disturbance because competition reduces diversity at low levels of disturbance and death reduces diversity at high levels of disturbance

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10
Q

IDH at low freq mild disturbance

A

more competitive exclusion ➞ org best suited to that situation/better competitors are ones surviving

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11
Q

IDH high freq, intense disturbance

A

death

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12
Q

1° succession

A

bare rock, no soil
* takes very long time to colonize

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13
Q

climax community

A

successional timeline has completed ➞ stable

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14
Q

2° succession

A

major disturbance kills plant community but soil remains
* soil ➞ nutrients & anchor for plants
* more rapidly: colonizers can start immediately no need for soil profile to develop

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15
Q

major disturbance events leading to 1° succession

A
  • meteor
  • glacier retreat
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16
Q

major disturbance events leading to 2° succession

A

fire

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17
Q

geographical isolation

A

prezygotic barrier where org are physically separated and cannot come into contact

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18
Q

habitat isolation

A

prezygotic barrier of georaphical isolation where org occupy diff parts of same habitat and do not come into contact
* stickelback fish
* stickbug on adjacent plants
* hawthorne insects

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19
Q

mechanical isolation examples

A
  • flower shape
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20
Q

behavioral examples

A
  • flower shape
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21
Q

fires in Mediterranean ecosystems

A
  1. Pine Fire syndromes
  2. chapparal shrub syndromes
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22
Q

Pine Fire syndromes

A

mediterranean ecosystem fires:
1. fire tolerators: tolerates fire with goal of surviving
* ex: tall, no branches at bottom, very thick bark, long needles
2. fire embracers: lean into fire to trigger next generation
* short, thin, flammable, light up quickly
* open cones & disperse seeds when exposed to heat
* cannoy reproduce w/out fire

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23
Q

chapparal shrub syndromes

A

mediterranean ecosystem fires:
1. fire recruiters: adult plant dies but has been dropping seeds into soil that are triggered by heat & germinate immediate after fire
2. fire persisters: above-ground portion is burned away by root mass survives & plant can resprout from root mass

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24
Q

prairie fires

A

intentionally set to promote regrowth
* commensalist interaction btwn trees/shrubs

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25
Q

early successional species characteristics

A
  • short lifespan
  • rapid reproduction
  • many small seeds
  • early reproductive age
  • small bodies
  • rapid growth
  • bad competitors
  • boom/bust population growth
  • r-selected
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26
Q

late successional species characteristics

A
  • long lifespan
  • slow growth
  • produce few large offspring
  • late reproductive cycle
  • better competitors
  • large bodies
  • stable pop size
  • K-selected
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27
Q

competitive exclusion principle

A

2 species competing for the same limiting resources cannot coexist ➞ eventually the stronger competitor will drive the weaker competitor extinct

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28
Q

ways to avoid competitive exclusion principle

A
  1. resource partitioning
  • separating habitat into physical parts, like lizards in their parts of tree/shrubs
  • separating habitat into “parts” like wavelengths for understory plants or pollinators based on color or shape
  1. character displacement: species competing for same limiting resources diverge in morphology due to NS
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29
Q
A

lotka-volterra equation for prey pop

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30
Q
A

lotka-volterra equation for predator pop

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31
Q

lotka-volterra equation terms that represent reciprocal density dependence in population sizes of predators and prey

A

V & P

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32
Q

lotka-volterra equation term that represents the growth rate of the predator population

A

cpV
victim pop size × predation rate × conversion efficiency

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33
Q

why are the lotka-volterra equations formulated from the exponential growth equation and not from the logistic growth equation

A

they believed that the primary driver for pop size for each was the others’ pop size & neither would reach K so it is irrelevant

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34
Q

Why might natural selection favor a predator that is LESS efficient, or a disease/pathogen that is LESS virulent?

A
  • if a predator is too efficient then it drives prey extinct & itself following
  • If pathogen kills host then it dies too
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35
Q

consumption efficiency

A

how much do you eat of the amount of biomass available

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36
Q

assimilation efficiency

A

how much of what you consume is digested

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37
Q

production efficiency

A

how much biomass can you produce from what you digest

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38
Q

ecological efficiency

A

proportion of net primary energy that becomes net secondary energy

consumption x assimilation x production efficiencies

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39
Q

Lindeman’s law of 10%

A

~10% of energy available at one trophic level is transferred to the next

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40
Q

to determine how many trophic levels an ecosystem can support

A
  1. available energy through primary productivity
  2. efficiency of energy transfer across tropic levels
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41
Q

important roles/identities that org have in their trophic interactions

A
  1. keystone species: very high impact on diversity despite being rare
  2. foundation species: physical bodies make up habitat for other org
  3. ecosystem engineer species: physically alter habitat
42
Q

keystone species examples

A
  1. prairie dogs burrows house other org & create patchiness gives diversity of plants that attract diverse primary consumers ➞ promotes diversity at all higher trophic levels
  2. seastars control prey pop sizes which increases diversity by preventing competition btwn prey species
43
Q

foundation species examples

A
  1. corals
  2. trees
  3. kelp
44
Q

ecosystem engineer species

A

beavers’ damns alter water flow & promote species richness

45
Q

tropical rainforest

A
  • high precipitation w/ little/no seasonality
  • high temp with no seasonality
46
Q

Desert

A
  • extremely low precip with little/no seasonality
  • generally high temp with high seasonality
47
Q

Temperate deciduous forest

A
  • medium precip (higher than grassland but not as high as rainforest) with no seasonality
  • medium temp with seasonality
48
Q

Grassland

A
  • high seasonality in temp and precip
  • wet season occurs during the warm season
49
Q

Boreal forest

A
  • low precip with some seasonality
  • generally low temperatures (~6 months below 0 C) and high seasonality in temp
50
Q

Tundra

A
  • low precip (but not as low as a desert) with some seasonality
  • very low temperatures (~9 months below 0 C) and high seasonality in temp
51
Q

Mediterranean

A
  • high seasonality in temp and precip
  • wet season occurs during cold season
52
Q
A

tropical rainforest

53
Q
A

desert

54
Q
A

temperate deciduous forest

55
Q
A

Boreal forest

56
Q
A

artic tundra

57
Q
A

temperate grassland

58
Q
A

mediterranean

59
Q

Anthropocene

A

era when human activities are the dominant influence on climate & the envir

60
Q
A

grassland in S

61
Q
A

tropical rainforest at equator

62
Q
A

desert in N

63
Q
A

temperate deciduous in N

64
Q
A

desert in S

65
Q
A

mediterranean in N

66
Q
A

grassland in N

67
Q
A

mediterranean in N

68
Q
A

arctic tundra

69
Q
A

boreal forest in N

70
Q
A

tropical rainforest at equator

71
Q
A

mediterranean in S

72
Q

Would you expect the production efficiency to be higher for an ectotherm or an endotherm?

A

ectotherms

73
Q

aquifers vs oil, & coal

A

‘fossils’ as they come out of the ground, are slow to replenish but they do not form from fossils

74
Q

extinction vortex

A

path to extinction where every step pushes a species closer and closer
1. human or natural disturbance event
2. smaller pop size results
3. genetic drift, inbreeding, random pop size decrease genetic diversity & make pops more susceptible & less likely to withstand
4. reduced fitness
5. lower reproduce & higher mortality
6. smaller pop ➞ cycle continues until extinction

75
Q

Nₜ = N₀ert

A

predicting population size under exponential growth

76
Q

age demographics and r

A

r correlates to the proportion of indiv in their reproductive ages

  • ↑ proportion of indiv in reproductive age = higher growth rate
  • ↓ proportion of indiv in reproductive age (majority of pop post-reproductive age) = slower growth rate
77
Q

both homozygotes are overrepresented

A
  1. inbreeding
  2. natural selection- diversifying
78
Q

hamilton’s rule

A

defines how benefits to close relatives (↑ reprod output) can outweigh costs to the altruist (own lost reprod output from altruistic event)

  • when is kin selection supported by natural selection

r B > C

r = coefficient of relatedness: fraction of genes shared

B = benefit to relative: ↑ in offspring for relative

C = cost to altruist: loss of offspring for altruist

  • ↑ benefits or relatedness incurs a higher cost
79
Q

exceptions to hamilton’s rule:

A
  1. reciprocal altruism: altruist has reasonable expectation that sacrifices will be reciprocated in the future
  • repeated interactions
  • non-related indiv
  • ex: vampire bats
  1. sexual selection: displays of altruism ↑ mating options
80
Q

linkage

A

genes close to each other on the same chrom will be inherited together

  • disproportionate ratios btwn gametes
  • if AB are on same chrom & BC are on the same chrom, then A & C are on the same chrom
81
Q

recombination freq

A

genes on diff chrom: expect nearly equal proportion of the 4 diff types of gametes

genes on same chrom: proportions of gametes are not equal

  • majority = non-recombinant (linked)
  • minority = recombinant
82
Q

pleiotropy

A

one gene affects multiple diff traits/phenotypes

83
Q

polygenic inhertence

A

one trait is additively controlled by many genes

  • phenotype controlled by combination of many different genes
  • every gene is allowed to act
  • continuous distribution
  • range/variation of phenotypes
  • ex: height, color
84
Q

epistasis

A

multiple genes interact to determine phenotype

  • one gene can mask another
85
Q

gene flow

A

migration: movement of alleles through indiv or their gametes

  • new allele introduced to pop ➞ changes allele/gene freq ➞ starts out low but allele becomes more common
  • w/in pop: ↑ gene variation
  • homogenize distant gene pools/pop
  • org can migrate without moving
           - ex: pollen, marine animals
86
Q

genetic drift

A

chance events in small pop cause unpredictable changes in allele freq

  • random
  • rare alleles are lost entirely after a single generation in small pop
  • random event effects are stronger in smaller pop
  • graph w/ many squiggles
  • reduces gene diversity
  • ↑ homozygosity ↓ in heterozygosity
  • can be stronger than NS

when given observed & expected w/in pop size, cannot predict which direction drift will shift in freq

87
Q

consequences of genetic drift:

A
  1. loss of overall diversity through loss/fixation of alleles
    • no gen diversity ➞ cannot adapt
  2. ↑ in deleterious recessive conditions
  3. ↑ susceptibility to future stressors
88
Q

random mating

A

only occurs when every indiv has an equally likely chance of mating with another

89
Q

HWE: non-random mating influences

A
  • sexual selection
  • mate preference
  • proximity
90
Q

inbreeding

A

mating between relatives

  • familial relatives
  • ex: cousins, 2nd cousins etc

↓ level of heterozygosity & ↑ homozygosity compared to expected

91
Q

HWE: non-random mating consequences

A
  • inbreeding ↓ heterozygosity & ↑ homozygosity
  • homozygotes are overrepresented
  • inbreeding ↑ freq of deleterious recessive alleles
92
Q

HWE: NS consequences

A
  • fit alleles are overrepresented in future gen
  • ↓ freq of unfavorable traits
  • favors particular alleles over others
  • directed selection
93
Q

Nᵪoff

A

of offspring of indiv at age x

94
Q

lᵪ

A

survivorship: where is mortality primarily occurring

  • lᵪ = Nᵪ ÷ N₀
95
Q

mᵪ

A

fecundity: avg # of offspring each indiv has at that age

  • mᵪ = Nᵪoff ÷ Nᵪ
96
Q

lᵪmᵪ

A

what age group has the most offspring

97
Q

G

A

generation time: avg age of reproduction

  • should be close to age where most reproduction occurs (lᵪmᵪ)
  • G = ∑ xlᵪmᵪ ÷ ∑ lᵪmᵪ
98
Q

R₀

A

net reproductive rate: avg # of offspring each indiv has throughout their lifetime

  • R₀ = ∑ lᵪmᵪ
  • R₀ = 1 ➞ pop size is not changing
  • cannot be negative
99
Q

relationship between R₀ and r

A

when R₀ = 1, r =1 ➞ every indiv is replacing themself in future gen

when R₀ > 1, r > 0

when r < 0, R₀ < 1 (but greater than 0)

100
Q

what contributes to genetic diversity?

A
  1. sexual reproduction mixes whole genomes from 2 diff pop
  2. independent assortment mixes sets of chrom & allows org to make genetically unique gametes
  3. recombination mixes alleles on a chrom ➞ creates new chrom combinations diff than inherited
  4. mutations
101
Q

one homozygote is overrepresented

A

long-term drift

102
Q

heterozygotes are overrepresented

A
  1. outbreeding

2 natural selection - stabilizing

BIS 2B (4 decks)

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