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BIS 2B > final > Flashcards

final Flashcards

(102 cards)

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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
early successional species characteristics
* short lifespan * rapid reproduction * many small seeds * early reproductive age * small bodies * rapid growth * bad competitors * boom/bust population growth * r-selected
26
late successional species characteristics
* long lifespan * slow growth * produce few large offspring * late reproductive cycle * better competitors * large bodies * stable pop size * K-selected
27
competitive exclusion principle
2 species competing for the same limiting resources cannot coexist ➞ eventually the stronger competitor will drive the weaker competitor extinct
28
ways to avoid competitive exclusion principle
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 2. character displacement: species competing for same limiting resources diverge in morphology due to NS
29
lotka-volterra equation for prey pop
30
lotka-volterra equation for predator pop
31
lotka-volterra equation terms that represent reciprocal density dependence in population sizes of predators and prey
V & P
32
lotka-volterra equation term that represents the growth rate of the predator population
cpV victim pop size × predation rate × conversion efficiency
33
why are the lotka-volterra equations formulated from the exponential growth equation and not from the logistic growth equation
they believed that the primary driver for pop size for each was the others’ pop size & neither would reach K so it is irrelevant
34
Why might natural selection favor a predator that is LESS efficient, or a disease/pathogen that is LESS virulent?
* if a predator is too efficient then it drives prey extinct & itself following * If pathogen kills host then it dies too
35
consumption efficiency
how much do you eat of the amount of biomass available
36
assimilation efficiency
how much of what you consume is digested
37
production efficiency
how much biomass can you produce from what you digest
38
ecological efficiency
proportion of net primary energy that becomes net secondary energy consumption x assimilation x production efficiencies
39
Lindeman's law of 10%
~10% of energy available at one trophic level is transferred to the next
40
to determine how many trophic levels an ecosystem can support
1. available energy through primary productivity 2. efficiency of energy transfer across tropic levels
41
important roles/identities that org have in their trophic interactions
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
keystone species examples
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
foundation species examples
1. corals 2. trees 3. kelp
44
ecosystem engineer species
beavers' damns alter water flow & promote species richness
45
tropical rainforest
* high precipitation w/ little/no seasonality * high temp with no seasonality
46
Desert
* extremely low precip with little/no seasonality * generally high temp with high seasonality
47
Temperate deciduous forest
* medium precip (higher than grassland but not as high as rainforest) with no seasonality * medium temp with seasonality
48
Grassland
* high seasonality in temp and precip * wet season occurs during the warm season
49
Boreal forest
* low precip with some seasonality * generally low temperatures (~6 months below 0 C) and high seasonality in temp
50
Tundra
* 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
Mediterranean
* high seasonality in temp and precip * wet season occurs during cold season
52
tropical rainforest
53
desert
54
temperate deciduous forest
55
Boreal forest
56
artic tundra
57
temperate grassland
58
mediterranean
59
Anthropocene
era when human activities are the dominant influence on climate & the envir
60
grassland in S
61
tropical rainforest at equator
62
desert in N
63
temperate deciduous in N
64
desert in S
65
mediterranean in N
66
grassland in N
67
mediterranean in N
68
arctic tundra
69
boreal forest in N
70
tropical rainforest at equator
71
mediterranean in S
72
Would you expect the production efficiency to be higher for an ectotherm or an endotherm?
ectotherms
73
aquifers vs oil, & coal
'fossils' as they come out of the ground, are slow to replenish but they do not form from fossils
74
extinction vortex
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
Nₜ = N₀ert
predicting population size under exponential growth
76
age demographics and r
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
both homozygotes are overrepresented
1. inbreeding 2. natural selection- diversifying
78
hamilton's rule
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
exceptions to hamilton's rule:
1. **reciprocal altruism**: altruist has reasonable expectation that sacrifices will be reciprocated in the future - repeated interactions - non-related indiv - ex: vampire bats 2. **sexual selection**: displays of altruism ↑ mating options
80
linkage
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
recombination freq
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
pleiotropy
one gene affects multiple diff traits/phenotypes
83
polygenic inhertence
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
epistasis
multiple genes interact to determine phenotype - one gene can mask another
85
gene flow
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
genetic drift
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
consequences of genetic drift:
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
random mating
only occurs when every indiv has an equally likely chance of mating with another
89
HWE: non-random mating influences
- sexual selection - mate preference - proximity
90
inbreeding
mating between relatives - familial relatives - ex: cousins, 2nd cousins etc ↓ level of heterozygosity & ↑ homozygosity compared to expected
91
HWE: non-random mating consequences
- inbreeding ↓ heterozygosity & ↑ homozygosity - homozygotes are overrepresented - inbreeding ↑ freq of deleterious recessive alleles
92
HWE: NS consequences
- fit alleles are overrepresented in future gen - ↓ freq of unfavorable traits - favors particular alleles over others - directed selection
93
Nᵪoff
of offspring of indiv at age x
94
lᵪ
survivorship: where is mortality primarily occurring - lᵪ = Nᵪ ÷ N₀
95
mᵪ
fecundity: avg # of offspring each indiv has at that age - mᵪ = Nᵪoff ÷ Nᵪ
96
lᵪmᵪ
what age group has the most offspring
97
G
generation time: avg age of reproduction - should be close to age where most reproduction occurs (lᵪmᵪ) - G = ∑ xlᵪmᵪ ÷ ∑ lᵪmᵪ
98
R₀
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
relationship between R₀ and r
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
what contributes to genetic diversity?
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
one homozygote is overrepresented
long-term drift
102
heterozygotes are overrepresented
1. outbreeding 2 natural selection - stabilizing

BIS 2B (4 decks)

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