Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biogeography > Final > Flashcards

Final Flashcards

1
Q

What is a central aim in biogeography?

A

Classify the world’s biota into meaningful geographical units for analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Endemism is…

A

To occur in one place and nowhere else (singular species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Provincialism is…

A

Area of endemism, or, a coincident distribution of endemics in a particular place (multiple species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Disjunction is…

A

The occurrence of close relatives in widely separated areas (think ratites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the terms for the causes/patterns of endemism?

A

Autochthonous & Allochthonous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does it mean to be autochthonous? Give examples

A

When a species is endemic to an area because it originated there and never moved
- Radiations following colonization of remote islands
- Isolation of biotas by vicariance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does it mean to be allochthonous? Give examples

A

When a species is endemic to an area different from where it arose, due to the evolution of its range
- Pleistocene climate change caused species’ ranges to shift
- secular migration (shift in geographic range associated with evolutionary change; extinction in the area of origin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the terms for old vs young endemics?

A

Paleoendemic (old)
Neoendemic (young)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the pattern of endemism?

A

nonrandom! Species ranges tend to be aggregated into biogeographic regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are endemism patterns nonrandom?

A

Turnover within regions is relatively low & between regions, turnover is relatively high!

Species within regions may also tend to be more closely related; esp at larger spatial scales (this is due to time for speciation + dispersal = in situ origins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are key questions about biotic regions we should be asking?

A
  1. what criteria should be used to distinguish them?
  2. How many should be recognized?
  3. How do transition zones relate to geo history, geo features, and climate?
  4. How does recognizing regions help us conserve biodiversity?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Criteria for delimiting regions

A

Functional: Vegetation type (physiognomy)

Compositional (turnover in species occurrences - a taxonomic criterion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is functional classification of bio regions?

A

Classification of terrestrial biomes based on vegetation type due to its tight relationship with climate (temp and precip + soil conditions)

These biomes are NOT unique geographic regions; the same biome can occur in multiple places (Buffon’s Law -> different species in same biomes, due to convergent adaptations)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sclater vs Wallace COMPOSITIONAL Criteria

A

Compositional = taxa-based, so biome doesn’t occur in multiple places (Nearctic, Neotropical, Oriental, etc)

Sclater: 6 terrestrial regions based on bird distribution

Wallace: 6 terrestrial regions based on non-volant mammals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are compositional criteria? What are some interesting pattern examples?

A

Primary divisions following continental margins and major climatic patterns - taxon-based

Wallace’s & Lydekker’s Line -> Sunda and Sahul shelves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain geo history of Wallace’s and Lydekker’s Lines

A

Pleistocene: lowered sea levels exposed land connections between islands of each shelf, but the shelves themselves separated by deep water

Wallace’s line is north side of Wallacea, Lydekker is S side of Wallacea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Wallacea

A

Wallacea is seasonally dry monsoon climate (the area between Sahul and Sunda plates -> Australia and SE Asia)

Biota is characterized by high vertebrate endemism (40-60%)

Plant distributions less fidelity to the line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain how Sulawesi came to be

A

Largest island in Wallacea -> formed from convergence of 3 continental platese (Eurasian Sunda shelf), (Australasian Sahul shelf), and Pacific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many biotic regions should be recognized? Compositional-based, ofc

A

SCALE DEPENDENT: inherently hierarchical..but is this real or an artificial assumption imposed by our models?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Non-hierarchical model: Grade of Membership

A

motifs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are ecoregions?

A

Biotic regions delineated using both functional/compositional criteria for a specific purpose (like conservation)
- identify units for conservation action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are biodiversity hotspots?

A

regions identified where exceptional concentrations of endemic species undergoing exceptional loss of habitat are

Endemism + functional criteria (region of elevated threat to habitat degradation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Does Wallace’s Line represent a functional or compositional separation of biotic regions?

A

Compositional; turnover of taxa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do we know if a temperate group has tropical origins?

A

Fossil record (but what about lack of fossil record?)
- current geographic ranges + phylogenetic trees!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the way to infer the most probable ancestral area state?

A

Maximum Likelihood -> what set of ancestral states maximized the probability of the states at the tips if changes are constant rate?

Parsimony doesnt consider branch lengths -> if rate of change is low, then ML matches parsimony

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Geographic range is what type of property of a species?

A

Emergent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Modes of range evolution

A

Dispersal (expansion)

Local Extinction (range contraction)

Speciation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Explain Dispersal pattern with blob-o-gram

A
  1. Ancestral state (blob in one side)
  2. Dispersal (blob one side -> other side)
  3. Derived state (blob on both sides)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Explain Local Extinction pattern with blob-o-gram

A
  1. Ancestral state (blob on both sides)
  2. Local extinction
  3. Derived state (blob on only one side)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How many steps for a blobl to go from one side to the other side?

A

2 steps.
START: 1 side
- STEP to dispersal to other side
- STEP to extinction on ancestral side
END: 1 on other side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Explain speciation with blob-o-gram (node) (“SYMPATRIC”)

A

START: species in one area
- STEP of splitting in the one area
END: two species in the same area

  • The ancestral range is SUBDIVIDED but doesnt mean ecologically sympatric!!!!!!) can still be allopatric in region!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Explain speciation with blob-o-gram (node) (“VICARIANCE”)

A

START: one species in both regions
- STEP the one species is isolated between the two regions
END: now two species, one in each region

The ranges of the descendants do NOT match the ancestral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Explain speciation with blob-o-gram (node) (“PERIPHERAL-ISOLATE”)

A

START: one species in both regions
- STEP: budding in one region
END: one species with same distribution as ancestral area, one species with just range in the budded region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a speciation scenario that cannot happen in the blob-o-grams?

A

Ancestor AB may. NOT give rise to descendants AB & AB (you cant have ancestral area being both, then splitting in both regions at the same time, then both descendants having the same distribution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Dispersal-extinction-cladogenesis Model (DEC)

A

Range evolves by 2 modes:

  1. Anagenetic: dispersal & local extinction along branches
  2. Cladogenetic: subdivision and inheritance of ancestral range
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

In parsimony perspective, what events do not count in DEC?

A

Cladogenetic! only Anagenetic count (incur cost)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Larger ranges should have what affect on evolution of reproductive isolation?

A

Acceleration!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Ranges that span isolated regions should have what affect on evolution of reproductive isolation?

A

Acceleration! Reduced gene flow between isolated areas - like islands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is jump dispersal?

A

Instant speciation by dispersal to an isolated area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are the two ways area isolation accelerates speciation?

A
  1. Inhibition of gene flow
  2. isolated areas are more likely to have differences that promote local adaptation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What keeps biotas separate?

A

Barriers: transition zones between major regions (generally marked by physical features that inhibit dispersal - oceans, mountains, deserts)

Filters: permeable barriers via organisms adapted to withstand the crossing - no barrier is impermeable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Standstill Hypothesis

A

Human pops. diverged from Siberian ancestors 25kya -> beringia refugium during maximum; isolated until retreat 15-16kya for North American southward migration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

buffon’s law & evolutionary convergence

A

Environmentally similar but isolated regions have taxonomically distinct biotas

Species may have similar ecological traits that have convergently evolves (think sclerophylls in Mediterranean climates)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Explain the GABI broadly

A

Great American Biotic Interchange

S America isolated during Cenozoic from other continents (“splendid isolation”)
- endemic mammal fauna evolved (think monkeys rafting, sloths, capybara, monotremes etc)

Isthmus of Panama closes = land bridge (3-4Myr, versus new model - 15Myr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Explain GABI new “old isthmus” model

A

ancient river deposits of zircons = only come from Panama = 13-15myr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Explain GABI asymmetry

A

The net movement across isthmus is asymmetric, favoring a north to south colonization and diversification pattern (10% of north American species descend from S American immigrants versus 50% of S American species descend from N American immigrants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What explains this asymmetry in the GABI (specifically nonvolant mammals)

A
  1. Northern lineages superior migrators; pre-adapted for savanna habitats that dominate the isthmus in the Pleistocene
  2. Northern lineages superior competitors; evolved on larger and more diverse continent = more “battle tested”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is disjunction? Compare to Buffon’s Law

A

occurrence of closely related taxa in widely separated areas

Buffon’s Law: geographically isolated but environmentally similar regions harbor distinct communities of species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What were the two competing beliefs of range dynamics in the 19th century?

A

Catastrophism and Uniformitarianism (gradualism)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Explain catastrophism

A
  • periods of stasis punctuated by cataclysmic change (extinction & creation)
  • Georges Curvier
  • Species do not change
  • species ranges remain near site of creation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Explain uniformitarianism

A
  • geological processes are slow but continual (mountain building for example)
  • earth is ancient
  • Charles Lyell
  • species ranges can change
52
Q

How did uniformitarians explain species ranges across continents when at the time, it was thought that the position of the continents were fixed?

A

Extensionists -> (Hooker, Lyell) dispersal across ancient land bridges

Dispersalists -> (Darwin, Wallace) long-distance dispersal; eventually won over

53
Q

What were the two paradigmatic shifts of the 1970s?

A
  • plate tectonics (sequential fragmentation and separation of continents)
  • phylogenetic systematics (sequential branching of lineages)
54
Q

Synapomorphies

A

shared derived characters

55
Q

What are taxon-area cladograms?

A

branching history of species; substitute tips for areas

56
Q

What is Hennig’s Progression Rule?

A

Progressively derived lineages move away from the ancestral area (Think Elepaio)

57
Q

What is vicariance?

A

General patterns of disjunction caused by sequential emergence of barriers (phylogenies reveal vicariance history of the areas)

58
Q

What pattern does long-distance dispersal show?

A

None! it is idiosyncratic and lineage-specific - it holds no predictive power for explaining general patterns

59
Q

How might we falsify thee vicariance hypothesis?

A

The timing of divergence and timing of continental fragmentation do not align

Fossil taxon outside area of current occurrence

If many other clades do not show same pattern

60
Q

What is the general area cladogram and who inspired it?

A

GAC = hypothesis of area history intended to be a common cause/explanation of disjunct distributions across unrelated taxa (inspired by Nelson and Platnick); so a lot of taxon-area cladograms together

61
Q

What are inconsistent patterns with vicariance?

A
  • Failure to speciate
  • Redundant distributions (multiple endemic lineages to same region)
  • Missing distributions
62
Q

Three processes that lead to disjunction

A
  1. Vicariance
  2. Extinction
  3. Dispersal
63
Q

What does true congruence require?

A

Matching of topology of branching and the times of divergence

64
Q

Kinds of islands

A
  1. oceanic (volcanic)
  2. continental shelf
  3. continental fragment
  4. habitat
65
Q

What is the species-area relationship?

A

of individuals per species is lognormally distributed (few species are common, many are rare); richness increases with area sampled

66
Q

Linear log-log function for species-area relationship; explain terms

A

log(S) = log(c) + zlog(A)

S: species #
A: area sampled
z: how quickly number of species increases (slope)
log(c): expected # of species in 1 unit of area

67
Q

Island Species-Area relationship

A

Larger islands = more species

68
Q

How do values of z (slope) in the species-area equation change for islands vs mainland?

A

Islands: higher
Nested samples of mainland: lower

69
Q

Species-isolation relationship

A

of species declines with island isolation (exponentially or sigmoidally); isolation is measured in distance, barrier permeability, time, etc.

70
Q

Why do smaller islands have fewer species than equal-sized area of mainland?

A

Smaller populations are more prone to extinction

71
Q

Why do more-isolated islands have fewer species than less-isolated ones?

A

Less likely to be colonized by immigrants

72
Q

MacArthur and Wilson Equilibrium model of island biogeography

A

of species on an island is the net result of opposing processes (immigration and extinction)

73
Q

Explain S, P, I, and E in the island Equilibrium Model

A

S = # of speciees on an island (Immigration & Extinction = net)

P = theoretical maximum # of species available for immigration from mainland

I = immigration rate (declines as S approaches P)

E = extinction rate (increases as S approaches P)

74
Q

What type of equilibrium is the Equilibrium Model of Island Biogeo

A

dynamic and stable (new species arrive & others die; returns to equilibrium if disturbed)

75
Q

Explain island size and extinction relationship

A

smaller island = higher rates (size constrains population) & also, extinction due to stochastic fluctuations in birth and death

76
Q

Explain isolation and size for rates of immigration and extinction on islands; including equilibrium turnover and species number

A

Near island: higher rates immigration

Small island: higher rates extinction

Small Near Island: highest equilibrium rate of turnover

Large Far Island: lowest equilibrium rate of turnover

Largest S (# of species): large near islands

77
Q

What is the target area effect?

A

immigration rates should be higher on larger islands than smaller islands

78
Q

What is the rescue effect?

A

extinction rates should be lower on near islands due to conspecific immigration (gene flow) from mainland populations

79
Q

Does M&Ws equilibrium model consider evolution?

A

No! It is only ecological. It does not consider in situ speciation & endemism

80
Q

What is ecological release?

A

Colonization of a place devoid of pressures from competition/predation = allow shift/expansion in niche (pronounced on small remote islands)

81
Q

What is adaptive radiation?

A

single colonizing lineage diversifies into separate species with more specialized nichees

82
Q

List some Hawaiian radiations

A

Silverswords
Honeycreepers
Bidens (haha)

83
Q

What do the biotas of islands neither near nor far from a continental biota reflect?

A

Dynamics of:
- colonization from mainland
- colonization between islands
- adaptation and speciation within and between islands

84
Q

What are taxon cycles?

A

Colonization, adaptation, speciation, and extinction on archipelagos have distinct phases

85
Q

What is the evidence for taxon cycles?

A

Range size (endemism) and ecological differentiation
1. Initial expansion
2. Differentiation, specialization, speciation
3. Contraction
4. Relictual endemism

86
Q

What is the island rule of body size evolution in mammals?

A

Pervasive, but not universal, trend that on islands, small mammal species become larger (gigantism) and large species become smaller (dwarfism)

Also in birds, reptiles - but not amphibians

87
Q

Why does the island rule of body size in mammals happen?

A

Small species: ecological release from competition and predation = larger species niches open

Large species: ecological release from competitors in smaller niches & resource-limited = favor smaller size

88
Q

What is flightlessness driven by?

A

limited resources, ecological release from predators (reduction of metabolically expensive flight; gigantism)

89
Q

What are evolutionary consequences of flightlessness and reduced dispersal ability?

A
  • traits aiding in colonization now maladaptive (disperse past island bounds = nowhere to go; die)
  • reduced gene flow among islands and between populations = accelerate speciation
90
Q

What is Baker’s Law?

A

Self-fertilizing plants are more likely to colonize islands because only 1 individual is needed

91
Q

What is dioecy?

A

separation of sexes (often an outcrossing mechanism); sometimes comes after island colonization to replace self-incompatibility

92
Q

What scale are phylogeographic studies?

A

Shallower; focus on geographic patterns and processes

93
Q

What are some examples of questions you can ask in the study of phylogeography?

A
  • origination point
  • spatial genetic structure (how are populations bounded)
  • migration -> how/when and where has gene flow occurred?
  • historical demographics & spatial patterns
  • comparative phylogeographic historiees
94
Q

What was an early assumption about gene trees?

A

That they accurately represent phylogeny, but coalescence is stochastic…

95
Q

What is incomplete lineage sorting?

A

the stochastic coalescent event that does not follow true species relationships

96
Q

What is the probability of coalescence?

A

1/(2N)
N diploid individuals in each generation, two random alleles coalesce in generation previous

97
Q

What is the expected time to coalescence?

A

2N generations; geometric distribution, but coalescence is highly variable

98
Q

What is the multi-species coalescent model?

A

It provides the likelihood of a gene tree topology given a branching history of populations through time (takes into account topology, branch lengths (time), and branch widths (population size))

99
Q

What is the ideal gene for phylogeographic analysis?

A

One that coalesces rapidly and has a high rate of mutation (fast evolving genes!)

100
Q

What makes organellar genomes good for phylogeographic study? What makes them bad?

A

They are uniparentally inherited (haploid), meaning that their expected time to coalescence is ONE QUARTER that of autosomal nuclear genes - but it lacks recombination, so it acts as a single gene!

101
Q

What are common methods of NGS?

A

target enrichment (gene trees)
RADseq (SNPs)
WG resequencing (mapped to reference)

102
Q

Linked vs unlinked SNPs

A

linked SNPs: build gene trees (linked gene by gene)

unlinked: just SNPs in general; can still enable inference of population tree

103
Q

What models are best for shallow population histories?

A

Drift-based (unlinked SNPs & allele frequencies -> no mutation, just neutral drift)

104
Q

Explain D statistics / ABBA BABA test

A

Infer gene flow using 3 tips and an outgroup
ABBA = gene flow between inner branches

105
Q

Explain ABBA BABA frequencies and conclusions from them

A

Equal ABBA BABA = ILS

ABBA&raquo_space; BABA = gene flow between 1 and 2

(3, 2, 1, O)

106
Q

List the mass extinctions

A

Ordovician (445 Mya)

Late Devonian (370 Mya)

Permian-Triassic (252 Mya)

Triassic-Jurassic (201 Mya)

Cretaceous-Paleogene (65 Mya)

Anthropocene (current)

107
Q

What percent do anthropogenic biomes cover Earth’s ice-free land survace?

A

75%

108
Q

What are the evidences for the Anthropocene being a distinct epoch?

A

Technofossils (concrete, plastic, aluminum)
Fossil fuel combustion (black carbon)
Deforestation & road construction (erosion)
Geochemical signatures (pesticides)
Atmospheric carbon dioxide & methane
Global Temps & sea levels

109
Q

How have humans affected the distributions of species?

A

Extinction of native species

Spread of non-native species

Climate change-induced range shifts

New and altered selection pressures and niches

110
Q

What is the trend of island vs mainland extinctions caused by humans?

A

Mainland increased in 20th century

111
Q

What have we done that causes extinction?

A

Introduction of alien species, habitat loss

112
Q

What are extinctions preceded by?

A

Range contraction and subsequent collapse

113
Q

What are the melting range and contagion hypotheses?

A

Melting Range: extinctions proceed from edges towards core

Contagion: extirpation proceeds towards periphery (more common in observed range collapses - like taxon cycles)

114
Q

What is the Linnean shortfall?

A

incomplete knowledge of the total number of species out there, so rates of extinction are extrapolations

115
Q

What are some vectors of exotic species?

A

Agriculture
Transport
Pest control
Corridor creation (panama canal)

116
Q

What is the elevator effect?

A

Mountains and high-latitude regions are sensitive to change and experience highest rates of global warning. Species ranges shift upwards in response to warming, effectively causing species at the top to be driven to extinction because it is too warm

117
Q

What are some examples of how species have adapted/reacted to urban environments?

A
  • higher mutation rates
  • chemical defenses
  • decreased genetic diversity
118
Q

What are the reasons that we think biotic regions are hierarchical?

A
  • a range of a taxon is nested within the ranges of its higher taxa (species, genus, family)
  • strongest ecological forces shape the largest regional divisions and are weaker at smaller spatial scales
  • hierarchical sequence of continental fragmentation of Pangea
119
Q

What are biogeographically meaningful units?

A

organization that reflects responses to abiotic and biotic forces -> shared evolutionary history of lineages, shared tectonic history of areas

120
Q

What are the parameters controlling interchange (GABI)?

A

Dispersal Rates
Speciation & extinction rates of colonizing clades
(N clades migrators = >D; N clades competitors = >S or <E)

121
Q

Who were Nelson and Platnick?

A

Two guys who adapted vicariance hypothesis -> phylogenies are valuable to biogeography; reveal patterns of disjunction caused by vicariance

122
Q

Plant vs Animal patterns of vicariance with gondwana

A

animals = congruence
Plants = dispersal more frequent, discordant directions

123
Q

What is the pattern of phylogenesis (in situ speciation; evolution) on islands regarding size and distance?

A

Speciation to endemic species richness increases with isolation (time and distance)

123
Q

What is pseudo-congruence?

A

Matching topologies but not times

124
Q

What is the loss of dispersal ability in plants associated with?

A
  • island colonization
  • shifts from marginal disturbed habitats to stable interior forests (heavier seeds); taxon cycle
125
Q

What are the challenges of inferring population trees for phylogeography?

A

closely related & recently diverged lineages = short wide branches (so high discordance)
Mutation required to estimate gene tress - dont have much time to accumulate

126
Q
A

Biogeography (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions