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BIO3A: Processes 2 Patterns > S2: W7 (Dr. Hanlie) > Flashcards

S2: W7 (Dr. Hanlie) Flashcards

(64 cards)

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1
Q

Galapagos islands?

A

= a “hotbed” of speciation.

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2
Q

Why are the Galapagos islands a “hotbed” of speciation?

A

It’s because the islands arose from volcanic islands.

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3
Q

Speciation?

A

= process by which new species are formed.

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4
Q

Speciation = …?

A

Cladogenesis.

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5
Q

Modes of speciation? (3)

A

• Allopatric speciation.
• Parapatric speciation.
• Sympatric speciation.

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6
Q

“Patric”?

A

= place.

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7
Q

Allopatric speciation process? (4)

A

• Original population.
|
• Barrier formed.
|
• Populations in isolation.
|
• New distinct species after equilibrium.

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8
Q

Parapatric speciation process? (4)

A

• Original population.
|
• New niche entered.
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• In new niche.
|
• New distinct species after equilibrium.

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9
Q

Sympatric speciation process? (4)

A

• Original population.
|
• Polymorphism.
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• Within the population.
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• New distinct species after equilibrium.

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10
Q

Types of speciation in general? (2)

A

• Allopatric speciation.
• Non-allopatric speciation.

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11
Q

Types of allopatric speciation? (2)

A

• Allopatric speciation by vicariance/Vicariant speciation.
• Peripatric speciation.

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12
Q

Types of Non-allopatric speciation? (2)

A

• Parapatric speciation.
• Sympatric speciation.

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13
Q

What causes speciation to occur?

A
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14
Q

What can happen if drivers disappear?

A

Hybridization (uncommon).

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15
Q

Vicariant speciation?

A

= geographic isolation due to a barrier to dispersal & gene flow.

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16
Q

Egs of barriers? (4)

A

• Uplifting of mountains.
• Continental drift.
• Changes in the flow of rivers.
• Changes in environment (desertification).

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17
Q

Eg of Vicariant speciation?

A

Panamic porkfish & Porkfish.

• the former lives in the Pacific ocean & the latter lives in the Atlantic ocean.

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18
Q

Peripatric speciation?

A

= small, isolated population, usually on the periphery of a larger ancestral species gives rise to a distinct species (founder effect).

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19
Q

Peripatric speciation attributes? (2)

A

• Active dispersal into an area not previously occupied.
• Periphery is isolated.

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20
Q

Egs of Peripatric speciation? (2)

A

• Hawaiian picture-winged Drosophila.
• Mexican prairie dog.

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21
Q

Egs of Peripatric speciation? (2)

A

• Hawaiian picture-winged Drosophila.
• Mexican prairie dog.

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22
Q

Explain Hawaiian picture-winged Drosophila?

A

12 species arose from a single species that migrated from the mainland.

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23
Q

Explain Hawaiian picture-winged Drosophila?

A

12 species arose from a single species that migrated from the mainland.

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24
Q

Explain Mexican prairie dog? (5)

A

• Grassland ecosystems.
• Shifts in distribution related to Pleistocene climate change.
• Divergence from C. ludonicianus.
• Climate change promoted biogeographical substructure within Chihuahua descent.
• Population expansion resulted in secondary co tact between lineages of C. ludovicianus.

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25
What happens if separated populations come into contact after removal of barrier? (3)
• If reproductively isolated, no mating/no viable offspring. • If not completely reproductively isolated, may form secondary hybrid zone where hybrids are sterile/inviable/less fit. • Reinforcement of NS.
26
What happens if separated populations come into contact after removal of barrier if reproductively isolated (prezygotic/postzygotic)?
No mating/no viable offspring.
27
What happens if separated populations come into contact after removal of barrier if not completely reproductively isolated? (2)
• May form secondary hybrid zone. • Hybrids sterile/inviable/less fit.
28
Hybrids sterile/inviable/less fit attributes? (2)
• Lower rates of survival. • Eg due to epistatic incompatibility.
29
Eg of What happens if separated populations come into contact after removal of barrier?
Green-eyed tree frog.
30
Explain Green-eyed tree frog? (3)
• Habitat isolation. • Event = deforestation (remove trees for agricultural areas). • Evolved 2 different mating calls due to different habitat structure.
31
Non-allopatric speciation?
= speciation is initiated when there's incomplete geographic separation of two or more populations of an ancestral species.
32
Non-allopatric speciation attribute?
Limited gene flow continues to occur between populations, yet there is divergence.
33
Parapatric speciation?
= populations occur in adjacent regions with different selection pressures (eg in an ecological cline) or where 2 different habitats meet.
34
Parapatric speciation attributes? (2)
• Gene flow occurs bit "hybrid". • Especially if drivers are weak, we can have a zone of hybridization or secondary contact (ecological niche).
35
Egs of Parapatric speciation? (3)
• Grasses in the vicinity of mines. • Orchid Satyrium hallackii. • Carrion crow & hooded crow.
36
Explain eg 1 of Parapatric speciation? (2)
• Have diverged from neighbouring populations in: - tolerance to heavy metals. - flowering time. - self pollinate more frequently. • Eurasia (uncontaminated) & Northern Africa (mine waste).
37
Explain eg 2 of Parapatric speciation? (4)
• Separation by pollinator shift along ecological gradient. • Different pollinators. • One hawkmoth & other carpenter bee. • Proboscis vs spur length.
38
Explain eg 3 of Parapatric speciation? (2)
• The 2 species of crow meet. • There's a primary hybrid zone.
39
Sympatric speciation?
= occurs when one or more new species arise without geographical segregation of populations.
40
Sympatric speciation attributes? (6)
• Models postulate disruptive selection (eg in 2 microhabitats), which leads to Intermediate phenotypes (heterozygotes) that have low fitness. • May involve one or many loci. • Difficult to prove. • Occupy different microhabitats which leads to Intermediate phenotypes that have lower fitness. • Genetic differences result in reproductive isolation. • Should also be linked to mate selection.
41
Eg of Sympatric speciation?
Apple maggot fly.
42
Explain eg of Sympatric speciation? (5)
• Lay eggs on Hawthorn fruit. • Moved onto apples (shifted host). • Speciated sympatrically. • From Hawthorn to apples. • Timing of fruit mating differs.
43
What do we use to hypothesize modes of speciation? (3)
• Distribution maps. • Habitat & body size information. • Phylogenies.
44
Drivers of speciation? (6)
• Barrier. • Geographical distance. • Ecological. • Reproduction. • Genetic isolation (no gene flow). • Divergences (NS/SS).
45
Eg of where a competitor caused character displacement in a sympatric population?
Geospiza fortis & G. magnirostris.
46
Character?
= useful features that help species to exploit resources.
47
Types of character divergence? (2)
• Character displacement. • Character release.
48
Character displacement attributes? (5)
• Due to competition. • Control. • Character gets displaced. • Evolutionary divergence in resource-exploiting traits. • Caused by interspecific competition.
49
Chatacter release attributes? (3)
• No competition. • No control. • Takes advantage of variety of resources in the absence of competition.
50
Driver of something?
= what is the underlying cause behind a certain geographical speciation pattern.
51
General process in terms of character divergence types? (4)
Character release | Drought/event happens | Competitor introduced | Character displacement
52
Eg of character divergence types?
Geospiza fortis (medium ground finch).
53
Explain eg of character divergence types? (6)
• Daphne major. • Absence of small ground finch. • Medium ground finch. • Presence of new competitor (large ground finch). • Same species, different beak size. • Process: Character release | Drought happened ("killed" small beak variant) | Competitor introduced. | Character displacement (evolved a medium sized beak to "widen diet").
54
Explain Cactus finches? (7)
● Eg of Sympatric speciation. ● Males singing song type A had longer, wider beaks & ate cactus seeds in fruit. Males singing song type B had smaller, narrower beaks & ate insect larvae in cactus pads. ● Divergent selection. ● No two males with the same song type. ● Enforced by continuous climatic changes. ● No assortative mating by females. ● Territorial pattern disappears in wetter year (secondary pattern): • beak size is now intermediate. • songs are no longer different.
55
Cactus finches paper?
Grant & Grant, 1983.
56
Conclusion of Cactus finches? (2)
● Mate choice is not genetically correlated with the use of a particular niche. ● Drivers were weak & didn't prevent genre flow.
57
Explain Warbler finch? (4)
● Ecological adaptation in parapatry (song differences). ● Secondary contact phase (very little discrimination of heterospecific song). ● Two morphologically similar species. ● Occupy similar ecological niches.
58
Warbler finch paper?
Grant & Grant, 2006.
59
Explain Grey warbler finch & Green warbler finch? (4)
● Low levels of genetic divergence/genetic distance. ● Positive correlation between genetic distance & differences in maximum elevation (ecological differentiation ). ● Females have chosen to breed on islands with habitats similar to where they were born. ● Phylogram of mtDNA haplotypes & geographical location.
60
Grey & Green warbler finch paper?
Tonnis et al., 2005.
61
Grey & Green warbler finch conclusion? (2)
● Genetic relatedness among populations is associated with habitat similarity. ● Habitat choice explains genetic & habitat similarities.
62
Explain Disa draconis complex species? (6)
● Habitat isolation (2 adjacent in Western Cape). ● Horse fly (mountain form) with short spur length. ● Long-tongued fly (sandplain form) with long spur length. ● Orchid species have different spur length (evolve/diverge as such). ● If a short spur is in an environment with only long-tounged flies, they will evolve long spur length. ● Therefore, long spur goes with Long-tongued fly & vice versa.
63
Spur?
= part of a flower that allows itself to be pollinated.
64
Interpreting pattern of speciation from phylogeny attributes? (2)
• Dating the phylogeny relative to understanding the history of the landscape helps (historical biogeography). • Match phylogeny to distribution OR distribution to phylogeny.

BIO3A: Processes 2 Patterns (12 decks)

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