M1 Flashcards

1
Q

prezygotic barriers

A

prevent mating or fertilization if mating occurs

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2
Q

postzygotic barriers

A

prevent hybrid zygote from developing into fertile adult or their offspring from reproducing

genetic incompatibilities maintain species boundaries
* some proportion of offspring are less fit

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3
Q

types of prezygotic barriers

A
  1. temporal isolation
  2. behavioral isolation
  3. mechanical isolation
  4. gametic isolation
    1. habitat isolation
  • geographic
  • ecological
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4
Q

reproductive barriers

A
  1. prezygotic barriers
  2. postzygotic barriers
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5
Q

habitat isolation

A

prezygotic barrier: occupying different habitats ➞ never come into contact
1. geographic: lions & tigers
2. ecological: diff levels of same habitat
* fish who live at diff levels of same lake

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6
Q

temporal isolation

A

prezygotic barrier: breeding at diff times

  • ex: corals gametes dont come into contact b/c 1 hr diff in spawing
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7
Q

behavioral isolation

A

prezygotic barrier: do not recognize each other as potential mates

  • mating calls or dances
  • ex: fireflies’ light patterns
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8
Q

mechanical isolation

A

prezygotic barrier: physiological diff preventing copulation

  • ex: dragonfliy genetalia or snail’s shell
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9
Q

gametic isolation

A

prezygotic barrier: sperm cannot fertilize egg

  • species-specific protein recognition
  • ex: purple & red urchin habe jelly coat surrounds egg w/ compounds that recognize specific proteins ➞ sperm needs specific proteins to enter coat & diff ones to enter egg
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10
Q

types of postzygotic barriers

A
  1. reduced hybrid viability
  2. reduced hybrid fertility
  3. hybrid breakdown
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11
Q

reduced hybrid viability

A

offspring don’t complete development or have low survivorship

  • ex: yellow-belly & fire-belly toads’ hybrid offspring have low embryonic development & malformed jaws ➞ don’t eat ➞ cannot survive
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12
Q

reduced hybrid fertility

A

can make viable offspring but infertile

  • ex: horse + donkey ➞ mule b/c diff # of chrom
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13
Q

hybrid breakdown

A

offspring are viable & fertile but their offspring are inviable or sterile

  • ex: toad hybrid ➞ 75% survive backcross ➞ very few live to adulthood
  • hybrid cross ➞ hatchlings but no tadpoles or adults
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14
Q

microevolution

A

w/in species ➞ changes in freq of gene variant across gen

  • small-scale changes
  • short time-frame
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15
Q

macroevolution

A

speciation ➞ accumulation of many microevolutionary changes resulting in new groups
* long-scale changes
* LONG time-frame (geographic time-scales)

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16
Q

taxa (taxon)

A

group of org on a phylogenic tree

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17
Q

sister taxa

A

most closely related on a phylogenic tree
* don’t assume that taxa close together are most closely related

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18
Q

branch point

A

where 2 diff taxa diverge on a phylogenic tree

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19
Q

clades

monophyletic clade

A

groups of taxa

a group that includes all taxa descended from a specific common ancestor
* can make 1 cut ➞ cut off 1 branch

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20
Q

speciation vs extinction

A

speciation: creating new lineages
* barrier to gene flow ➞ genetic divergence ➞ reproductive isolation

extinction: removing branches, loss of lineages

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21
Q

modes of speciation

A
  1. allopatric - vicariance
  2. allopatric - founder effect
  3. parapatric
  4. sympatric
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22
Q

allopatric speciation - vicariance

A

geographic separation into separate pop through physiological barrier means species cannot physically come into contact and no gene flow gives rise to new species

  • ex: tectonic plates & penguins
  • ex: oxbow lakes formations
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23
Q

allopatric speciation - founder effect

A

small group of indiv separate from original pop & become geographically separate ➞ pop diverge & become reproductively isolated
* ex: european starlings (geographical isolation)
* ex: snails on diff islands have opposite habddeness so cannot mate (mechanical isolation)

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24
Q

parapatric speciation

A

part of pop moves into new pop still connected to original pop
envir gradient
* envir gradient
* extension of range
* ex: zinc mine grass (habitat & temporal isolation)
* bird ring species can recognize neighbors mating call but not others’ (behavioral)

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25
Q

sympatric speciation

A

species diverge in same geographic location ➞ species ranges overlap
* new niche forms w/in pop & indiv in new niche diverge
* ecological habitat isolation ➞ ex: limnetic fish at diff levels of the lake
* insects on adjacent host plants
ex: hawthorn insect vs apple insects ➞ ecological isolation but also temporal isolation because diff fruiting time

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26
Q

fastest speciation occurs with

A
  • rapid reproductive isolation
  • shorter lifespan = faster generation time = faster speciation
  • specialist pollinators
  • sexual dimorphism
  • low dispersal ability
  • terrestrial org
  • polyploidy
27
Q

specialist vs generalist pollinators

A

specialists only pollinate one specific type of flower ➞ barrier to gene flow ➞ faster speciation
* specific pollinator shape (niche) ➞ rapid reproductive isolation ➞ speciation
* insect herbivores must develop specific adaptations for plant materials & toxins ➞ once developed for 1 plant hard to develop for others

28
Q

sexual dimorphism

A

groups with higher sexual dimorphism have faster speciation & more species
* species w/ sexual dimorphism have choosy mates
* some indiv has novel characteristic that is more attractive ➞ makes a new species
* species that are more dimorphic have more non-random mating
without ➞ less likely to have choosy mates based on secondary sexual characteristics

29
Q

dispersal ability

A

groups with small wings have higher speciation rates ➞ can only go so far ➞ less gene flow

30
Q

aquatic vs terrestrial

A

higher speciation in terrestrial systems
➞ ocean has fewer physical barriers for gene flow

31
Q

evolutionary radiation

A

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

32
Q

adaptive radiation

A

burst of speciation occurs b/c a group of species adapts to new ecological niches

  • form of evolutionary radiation
  • ex: island introduction & european finch ➞ adapted to specific diets
    • variation in envir & narrow specialist abiotic range ➞ able to diversity into many species
  • ex: cali tarweed aparted to abiotic niches: elevation & precipitation
  • ex: anolis lizards partitioned single habitat in hawaii
    • allopatric speciation btwn islands
    • sympatric speciation w/in 1 island ➞ artitioning habitat on same island
33
Q

polyploid speciation

A

non-disjunction results in uneven # of chrom ➞ unable to perform meiosis ➞ infertile

34
Q

competition

A

both species are harmed
(even better competitor)

35
Q

amensalism

A

one species is harmed and the other is neither benefited nor harmed
* short-lived ➞ harmed species will just avoid

36
Q

commensalism
facilitation

A

one species benefits and the other is neither benefited nor harmed

37
Q

predation
parasitism
herbivory

A

one species benefits while the other is harmed

38
Q

mutualism

A

both species benefit

39
Q

symbiosis

A

an interaction btwn species living on/in one another
* can both negatively & positively affect a species’ realized niche
* positive symbiosis can raise K ➞ helping access resources more efficiently
* ex: mycorrhizae & N fixation
* negative symbiosis can lower K
* ex: parasite or disease reduces to density low enough that pathogen isn’t spread btwn indiv

40
Q

+/− interactions influences on realized niche

A
  • realized niche is reduced compared to fundamental niche ➞ predator could occur in more places but doesn’t given the species interactions
  • realized niche is expanded compared to fundamental niche ➞ species help attain nutrients/water ➞ can now live in previously intolerable envir
41
Q

+/− interactions influences pop regulation (growth dynamics)

A

negative interactions can lower K

  • ex: dis or parasite reduces K to density low enough that pathogen isn’t spread btwn indiv

positive interactions can raise K
* ex: mycorrhizal partner helps plant access resources more efficiently

42
Q

reciprocal density dependence

A

predictable changes in predation, survival, etc produce predictable oscillations in pred & pop sizes

43
Q

lotka-volterra model

A

prey: change in victim pop size through time = prey growth rate - death of prey due to predator (predation rate × predator pop size)
* pVP = death ➞ primary way prey are affected by predator through death

predators:
* predator birth rate (cp) ➞ birth of predators is based on resources coming from prey
* cpVP = birth ➞ primary way predators are affected by prey is through increased reproductive output
* c = conversion of prey ➞ predators = how efficiently does predator turn increasing resources from prey into increased offspring

44
Q

interspecific competition

A

better competitor = flatter line
* smaller diff in density from start to finish

worse competitor = faster rate of dying
* larger diff in density from start to finish

45
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

46
Q

resource partitioning

A

species share limited resources by using them in diff ways ➞ allows coexistence
1. diff phys areas of habitat
2. diff parts of resource
* pollinators ➞ based on colors & shapes
* photosynthesis ➞ using unused wavelengths

47
Q

character displacement

A

species competing for same limiting resources diverge in morphology due to NS
* when resource partitioning is coupled w/ selection in a physical trait that relates to competitive interaction
* helps separate what plant species they are feeding on ➞ reduces competition

ex: galapagos finch
* when occur allopatrically: small diff in beak size (overlap in beak size)
* when occur sympatrically: large diff in beak size (no overlap)

48
Q

facultative mutualism

A

not needed for either species to survive & reproduce
* optional interaction b/c can exist without
* ex: mycorrhizae ➞ plant & fungus can grow/reproduce, just better w/ interaction

49
Q

obligate mutualism

A

symbiosis with other species is necessary for survival & reproduction
* 1 or both species cannot survive or reproduce without interaction
* not optional
* specific to species
* ex: Yucca plant & moth: plant only place where moth can lay eggs & moth only pollinator for plant

50
Q

examples of obligate for parasite/herbivore but facultative for host/plant

A
  • certain tapeworms & sharks
  • pandas ➞ bamboo
  • koala’s ➞ eucalyptus
51
Q

conditional interactions

A

conditional to the envir: where/when

ex: plants & fungus:
* low water/nutrient availability: interaction = beneficial for both
* high water/nutrient availability: plant doesn’t need fungus to survive

   * investing in relationship where it is not getting anything in return ➞ giving sugar away for free
  • parasitic under ↑ nutrient availability
52
Q

primary drivers of biomes

A

annual precipitation & temperature

53
Q

tropical rainforest

A

high precipitation year round
high temperature year round
along equator b/c of hadley cell

54
Q

desert

A

very low precipitation
seasonality in temp
* most at ~30°N & 30°S
* driven primarily by Hadley cell
* S: june/july = cold season
* N: june/july = hot season

55
Q

temperate deciduous forest

A
  • seasonal temp
  • precipitation high year-round
56
Q

boreal forest

A
  • highly productive
  • highly seasonal
  • unevenly represented in the 2 hemispheres ➞ N only
  • drives oscillations in CO2 levels
57
Q

arctic tundra

A

very little precipitation
high seasonality in temp
only couple months above freezing

58
Q

temperate grassland

A

high seasonality in temp
high seasonality in precipitation
warm season = wet season

59
Q
A

temperate grassland

60
Q

Mediterranean or chaparal

A

high seasonality in temp
high seasonality in precipitation

61
Q
A

mediterranean or chaparral

62
Q

how to define ecosystems

A
  1. salinity
  2. flow & movement
  3. depth
63
Q

aquatic ecosystems & salinity

A
  • freshwater ➞ low salt content
  • brackish: where fresh & salt water meet/mix ➞ salt content between ocean & freshwater
  • extra salty bodies ➞ evaporation, bedrock
64
Q

aquatic ecosystems & flow & movement

A

flow & movement ➞ difference between fresh river & fresh lake
* stagnant vs flowing
* speed
* direction
* over terrain: waterfalls