Examples Flashcards

1
Q

Example of Divergent, Directional and stabilising selection

A

E.G Spadefoot toads
* 2 morphs 1) omnivore 2) carnivore -> separate feeding niches

Divergent S = mark recapture experiment showed less survival of intermediate morphs

Directional S = Carnivores shown to do better than omnivores

Stabilising S = Intermediate morphs selected for when other species are present and dominant

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2
Q

Example of heterozygote advantage

A

Sickle cell anaemia, heterozygote for gene means you are immune to malaria whereas homozygote Is detrimental

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3
Q

Frequency dependant selection

A

PFDS - Mullerian mimicry
NFDS - Batesian mimicry

NFDS - (Gigord et al 2001) -Negative frequency-dependent selection maintains a dramatic flower color polymorphism in the rewardless orchid ( purple selected for as bees perceive it as “novel” and are attracted to it)

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4
Q

Example of a steep + shallow CLINE

A

Steep CLINE = cryptic + conspicuous morphs of rock pocket mice, reasonable gene flow but high predation selection (wrong morph in wrong area = dead)

Shallow CLINE = Alpha

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5
Q

Primary Hybrid zone

A

Directed reading - ring species Linn et al

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6
Q

Secondary hybrid zone

A
  • Postglacial recolonization in European hedgehogs,
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7
Q

Example of reinforcement , RCD and magic trait/ direct system

A

E.G. Pied flycatchers (+ collared) - normally live in allopatry, when in sympatry males (P) change their plumage to make It different to C’s (female preference for plumage also changes) - the gene that is adaptive is linked to mating preference

EXAMPLE OF

1) Reinforcement
2) Reproductive character displacement
3) Magic trait / direct system

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8
Q

Example of peripatric speciation + founder effect speciation

A

E.G. Paradise Kingfishers (New Guinea)

  • small periphery population split off and colonised islands
  • each different island has own species which are morphologically different
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9
Q

Example of habitat isolation , hybrid inviability , sexual isolation and cryptic isolation

A

E.G. Timema Cristinae ( stick insect)

  • 2 different ecomorphs , specialised to 2 different host plants (demonstrate a level of reproductive isolation)
  • hybrids inviable as camouflage ineffective
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10
Q

Example of sympatric speciation

A

E.G Howea palm

  • thatch + curly palm
  • 1 island , 6 hybrids ever found
  • differing soil preference + phenology
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11
Q

Example of ecological character displacement

Inter species

A

E.G. Brook + ninespine stickleback

- when ninespines present, brooks show evidence of benthic living (stronger jaws + wider bodies)

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12
Q

Sexual selection vs Natural selection

A

E.G. Marine Iguanas of Galapagos

  • male size is sexually selected for
  • increase in size shown to have negative effect on male fitness (harder to maintain larger body in extreme conditions)
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13
Q

Examples of sexual selection being affected by : Food resources, predation , parasitism,

A

FR: Red crossbills - (10 ecotypes + minimal gene flow) females select based of feeding efficiency + strategies

Predation: Guppys, red spots attrative to females but increase predation

Parasitism: Common Yellow throat , females select for melanin based black marks (which are linked to immunity) , parasites can affect production of these black marks

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14
Q

Example of mutation accumulation

A

E.G. Huntingtons disease - caused by a dominant allele expressed at 30+ years old

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15
Q

Example of Antagonistic pleiotropy

A

E.G. gene that causes overproduction of sex hormones can cause cancer later on

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16
Q

Example of mullers ratchet

A

E.G. Chao et al. RNA virus

  • created 20 lines of RNA virus , fored genetic drift by randomly sampling 1
  • regrew a culture from that 1
  • repeated for 20 generations
  • fitness (growth rate) declined over generations
17
Q

Example of Red-queen dynamics

A

E.g. Morra et al (2011)

  • co evolved nematode with bacterial pathogen
  • resulted in higher rate of outcrossing
  • when population was made asexual = extinction
  • sexual populations were able to respond to parasitism pressures
18
Q

Costly sexual traits

A

1) Red deer antlers
2) Guppies bright tails + red spots
3) Macaw has large tails - aerodynamic costs

19
Q

Example of more than 2 mating systems

A

Ciliates - no sexual selection

20
Q

Example/evidence for sensory bias theory

A

Crested auklets

  • put ornament on least auklet
  • auklet showed significantly more courtship displays
21
Q

Examples of female choosiness for : fecund males, parenting ability and resources

A

1) Lemon tetra fish , females select for male who have not recently spawned (pipefish is opposite way round)
2) Mottled sculpin
3) Female scorpion flys swap copulations for gifts (prey)

22
Q

Example of fisherian run-away selection

A

e. g. Stalk eyed fly
- range of genetic dimorphism based on width of eyes
- experiment artificially selected flys from different lineages
- females from long stalk lineage always choose long eye stalk fly’s

23
Q

Example of chase away selection

A

E.g. Drosophila , toxic male semen

  • toxins in male semen reduce females lifespan
  • females evolve resistance
  • males evolve increasingly toxic semen ( kills other sperm + increases females egg laying rate)
24
Q

Good genes model

A

Peacocks

25
Q

Example of two-level selection + genome conflict

A

E.g. Y chromosome genes

  • for y chromosome female s= useless
  • y chromosome favours adaptations that bias sex allocation
  • Autosomal + X chromosomes have their own optima, selected to oppose any hypothetical Y adaption for sex bias
26
Q

Example of two-level selection + genome conflict

A

Mitochondria and host conflict
E.g. Yeast cells (petite) mutations
- defective mitochondria shorter so replicates faster
-selected for at mitochondrial level
- mutation has negative effects on yeast cell (impairs cellular growth)

clear genome conflict

27
Q

Segregation distortion

A

Drosophila male SR gene

- however males with SR bred half as much

28
Q

Example of antagonism herbivory behaviour + coevolution

A

1) Passiflora (passion flower) , vines have cytotoxins in them
2) Heliconius caterpillars , can detoxify and disable them for use against predators

29
Q

Example of altruism

A

Beldings ground squirrels, call to alert for predators, singles them out

30
Q

Examples of eusociality

A

naked mole rats