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Biogeography Flashcards

1
Q

What is biogeography? Why is it a composite science?

A

Study of species’ distributions in space and time. It is a composite of ecology (niche theory, community ecology), evolution (speciation), and earth sciences (geology)

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2
Q

How are spatial patterns of biodiversity explained by physical and biological processes?

A

History: origination, extinction, dispersal, evolution of physical environment

Ecology:
- biotic and abiotic interactions

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3
Q

Where organisms live, it is related to their environment. How?

A

Abiotic characters, such as climate and substrate or temperature, salinity, light, pressure

Biotic factors such as interactions (competition, mutualism, parasitism etc)

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4
Q

What does it mean by referring to the “geographic template?”

A

The geographic template is the foundation of all biogeographical patterns, characterized by PREDICTABLE PATTERNS OF CHANGE ALONG MAJOR GRADIENTS (latitude, elevation, salinity, depth, etc)

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5
Q

What are the two Great Engines?

A
  1. Energy from the Earth’s core (plate tectonics - mountains & volcanoes)
  2. The Sun (primary productivity and heat from radiant energy -> wind, precipitation); higher latitudes cooler due to solar radiation dispersing over greater surface area
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6
Q

What is convection? Describe the basic pattern across the hemispheres and each cell name

A

Convection is when heated tropical air rises, is replaced by cooler surface winds and then descends (so from 0 degrees to 30 degrees; Hadley - then 30-60; Ferrel and 60-90; Polar)

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7
Q

What is the Coriolis Effect? Explain the types of winds and their directions

A

Coriolis effect: points at higher latitudes travel shorter distances per rotation, so winds to the N or S deflect to the right above the equator and left below it.
Trade Winds: westward approaching equator
Westerlies: Eastward Winds between 30-60 deg. latitude

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8
Q

What are Trade Winds? What are Westerlies?

A

Trade Winds: westward approaching equator

Westerlies: Eastward Winds between 30-60 deg. latitude

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9
Q

Explain how ocean currents are affected by Trade Winds and Westerlies

A

Trade Winds: make currents westwards at equator

Westerlies: cause currents to go eastward at higher latitudes

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10
Q

Explain directions of oceanic gyres in different hemispheres

A

N: Clockwise
S: Counterclockwise

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11
Q

Explain precipitation and elevation relationship

A

Hot air rises, cools (losing density and pressure - like refrigerators - reduced greenhouse effect); condenses and causes precipitation and then dry air

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12
Q

What is the greenhouse effect?

A

Retention of radiant heat from the Earth’s surface

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13
Q

Explain precipitation pattern across latitude

A

Warm air equator -> rainfall at low latitudes & mid-elevations = tropical rainforests
30N/S -> cool air descends and causes aridification (deserts and mediterranean)

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14
Q

How does soil form?

A

Weathering: mechanical breakdown (wind, water, heat)
chemical breakdown (water, CO2 - dissolve solutes)
Biological breakdown: CO2 and organic acids from lichens

Also: Organic material decay

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15
Q

Names of soil formation and the regions

A

Temperate: Podzolization (cool and precipitation)

Tropical: Laterization (warm and precip)

Arid Grasslands: Calcification (cool to hot, no precip)

Tundra (cold; moist)

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16
Q

When did biogeographers accept plate tectonics?

A

mid 1900’s

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17
Q

Who was Alfred Wegener, what did he do?

A

Developed continental drift theory; Pangea-> but did not have the mechanism!

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18
Q

What is the mechanism behind continental drift?

A

plate tectonics; CONVECTIVE forces of molten rock in asthenosphere -> pushing and pulling

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19
Q

Explain the major plate patterns through time
220 MYA
80 MYA
65 MYA
40 MYA
10 MYA
30 thousand YA

A

220: Gondwana (Triassic)

80: Tethyan Seaway (Cretaceous)

65: Cretaceous-Paleocene boundary

40: Eocene (Mediterranean N Africa)

10: Mid-Miocene, similar today

30-18 TYA: Last Glacial Maximum

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20
Q

What is vicariance biogeography? What inspired it?

A

Vicariance Biogeo: Study of disjunct distributions to find the treelike historical signal of continental breakup

Inspired by: Plate tectonics

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21
Q

What were the tectonics and climate of the Cenozoic like?

A

Gondwana collides with Eurasia = HIMALAYAS (Alps, Pyrenees etc)

Wallacea contact & Land bridge of North

Diversification of mammals, birds, plants

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22
Q

What were the tectonics and climate of the Paleocene?

A

66-65 MA
- Tropical climate (Ice-free poles)
EXTENSIVE tropical rainforests

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23
Q

What were the tectonics and climate of the Eocene?

A

56-34 MA
- Thermal maximum = ocean acidification
- Tropical climate at high latitude (think palm trees wyoming)
- Cooled later = antarctic ice sheet
- Mediterranean sea forms

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24
Q

What were the tectonics and climate of the Oligocene?

A

34-23 MA
- MAJOR cooling, ice expansion, seasonality
- C4 photosynthesis origin (CAM too)
- S America and Africa isolated

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25
What were the tectonics and climate of the Pliocene?
5.3 - 2.58 MA - Climate warmer, sea levels higher - Climatic oscillations - Arctic Ice Cap - GABI! - Homo
26
What were the tectonics and climate of the Quaternary?
2.58 - 0 MA Glacial-Interglacial Cycles - Milankovitch Cycles drive these cycles
27
What feedback effects occur during milankovitch cycles?
- Albedo (from ice extent), changes in CO2 with plant productivity
27
Explain the Milankovitch Cycles
Varies from a circular to elliptical orbit which lasts 90,000, 41,000, and 22,000 years In a more elliptical orbit, there is a greater difference in solar radiation between summer and winter.
28
What is geographic range?
Locations where all individuals of a species occur; An emergent property; product of a species' physiology, ecology, and evolutionary history; fundamental unit underlying biogeographic patterns
29
What is an irruption?
Movement in years of resource change
30
Why is range tricky regarding the concept of species?
Because defining a species is tough! Range is an emergent property (group thing), so you have to decide what the group is
31
What is the basis of range? Specifically, the "atomic basis"
Record of occurrence (like photo, museum specimen, etc) - Surveys, Community Science, inventories, museums
32
What are the types of maps?
Dot Outline Contour Predictive
33
What are dot maps?
Precise locations; biased; fixed in time
34
What are outline maps?
Informed subjective estimate of occurrence -> occurrence, geography, climate, ecosystem, physiology included in the making
35
What are Contour Maps?
Maps of abundance; hard to do unless a lot of sampling; interpolation required
36
What are predictive maps?
Species distribution models -> correlate occurrence with environmental variables and predicts suitable habitat areas
37
What are some problems and considerations for making range maps?
- Quality of data inconsistent; sampling bias (roads) - Core range vs outliers - Native vs invasive ranges
38
What is a Wallacean Shortfall?
For most species we know very little about range, esp. thru time.
39
What are the 2 quantities for measuring geographic range? Measuring is important for comparison!
1. Extent of Occurrence (along a dimension; distance, latitude, elevation) 2. Area of Occupancy (2D; ellipse, hull, area over grid)
40
What questions can be answered with comparing the extent of occupancy of a species?
- Ecological niche relationship - Extinction Risk - Gene Flow - Dispersal Ability - Phenotypic Plasticity
41
What are ways to measure area of occupancy?
Ellipse Convex Hull Grid Cells
42
What is Spatial Dispersion? What are the patterns?
- Distribution of points (organisms) - Clumped, Random, Even SCALE-DEPENDENT
43
What is important about cells and grids for area of occupancy?
It is SCALE-DEPENDENT! Think about the spatial dispersion
44
What size are most ranges?
Small!
45
What is something that determines range sizes?
Body Size (constraint against large body and small range)
46
What is Rapoport's Rule?
Range increases with latitude (and elevation, sea depth)
47
Why are ranges bigger at higher latitudes and elevations?
Physiological limits (fitness)
48
What is Hutchinson's Niche Concept
Curve over all relevant aces of variation -> n-dimensional hypervolume = Fundamental Niche!
49
What did Janzen say about mountains and what is the reasoning?
Mountain passes are higher in the tropics; the seasonality of temperate mountains is greater, so species have wider niches and can cross mountains more easily vs highly specialized tropical species
50
What is the fundamental niche?
the full range of environmental conditions under which an organism can live
51
Give an example of range limited by physiological requirements
Plants - like Saguaro Cacti - ranging to the frost zone (die from cavitation and prolonged freezing)
52
What limits geographic range?
abiotic factors (temp, soil moisture, elevation), dispersal ability, disturbance (fire) and biotic factors (predation, competition, parasitism)
53
What is the realized niche?
where and how a species is actually living; the combination of realized environment and fundamental niche limited by abiotic and biotic factors
54
What is competitive exclusion?
the inevitable elimination from a habitat of one of two different species with identical needs for resources.
55
What is parapatric competitive exclusion?
When ranges are adjacent (not overlapping) of incredibly similar species, suggesting competitive exclusion processes
56
What is Gause's Law
Species competing for the same limited resource cannot stably coexist
57
What is an example of natural experiments of competitive exclusion?
Local absences show competitors respond to absence of competition
58
Explain the barnacles thing
- too high and they desiccate - too low and they compete - the lower ones kept at bay with the snails
59
What is Dobzhansky-MacArthur Phenomenon?
Poleward range limited by physiological constraints and equatorial range enforced by biotic factors
60
What are equilibrial limits? These are things other than niche that determine range size
Independent of time; geometric constraint, habitat availability, climatic variability, dispersal, body size, mating system
61
What are some non-equilibrial limits to range size? What are patterns of this?
Dispersal Barrier changes (GABI, post-glacial migration_ Patterns: Stasis, idiosyncratic, age-and-area, stasis post expansion, species age
62
Explain Time for Dispersal vs Time for Adaptation
- What limits expansion of range? is it dispersal or adaptation? DISPERSAL: if you transplant core and periphery, no negative impact on fitness ADAPTATION: transplant and negative affects to the transplanted group
63
What is species distribution modeling?
Mapping the fundamental niche; combines occurrence with environmental variables and predict suitability
64
Steps to do SDM
1. Gather occurrence data 2. Gather enviro data 3. Extract enviro conditions at occurrence points 4. build model (probability) - absence data gives priors! 5. Project model in geographic space 6. evaluate model with K-fold cross validation
65
Does SDM truly estimate the fundamental niche?
Sorta - it CORRELATES; response curve is limited to range of variation in region studies, so if extremes of an axes, no clue how would respond past the extreme
66
Buffon's Law
Isolated regions with similar climates have distinct species assemblages
67
What is phylogeny?
Ancestor-descendant relationships based on genetic information; genes & populations & lineages
68
Tokogenetic:
Ancestor-descendant relationships of individuals
69
Phylogenetic
Ancestor-descendant relationship of populations/species
70
Evolutionary species concept
species: organisms that maintain identity from others; independent evolutionary fate and historical tendencies
71
What things do species concepts emphasize?
Relatedness (history) or Ecology
72
What is relatedness in species concepts?
- Exclusive groups more closely related to each other than outsiders - phylogenetic species concepts (monophyly) - looks at the past
73
What role is ecology used for in species concepts?
- Distinct ecological niches - reproductive isolation - biological, ecological, trait-based concepts - predict future
74
What goes into geographic models of speciation?
Range expansion + genetic/ecological differentiation - gene flow (think mountains)
75
What is a ring species?
Interbreeding between adjacent pops, but terminal pops cannot interbreed
76
What is Dobzhansky-Muller incompatibility?
genetic isolation negative epistasis; geographic isolation & mutations; secondary contact doesnt allow for hybrid
77
What is allopatric speciation? Can it be ecological? What about not?
geographic isolation which results in speciation; yes can be both ecological and nonecological
78
What does sympatric speciation require?
ecological differentiation (or chromosome stuff - polyploidy)
79
Vicariance vs Founder Event
Vicariance: mountains; population split, no huge Ne change Founder/peripheral: tiny founder population; diversity reduced
80
What does secondary contact do after allopatric divergence?
It can drive character displacement! -> no stable coexistence in sympatry with niche stuff
81
Radiation
Speciation events in rapid succession in a clade
82
Adaptive Radiation
speciaton event = ecological!; or nonecological followed by ecological differentiation; can be sympatric
83
Nonadaptive Radiation
Nonecological speciation; descendants are allopatric or parapatric from competitive exclusion
84
Modes of range evolution
Dispersal (expansion) Local Extinction (contraction) Speciation
85
What is dispersal?
Movement away from birthplace (often during particular life history stage); this influences demography; it is a limiting factor in realized range of a species
86
What ISNT dispersal?
Migration (seasonal ranges) Nomadism (irregular response to resource) Vagrancy (unpredictable few individuals; hurricanes)
87
Why disperse?
- reduce competition - increase fitness in higher quality enviros - reduce risk of extinction
88
When might selection favor shorter vs longer dispersal?
Shorter: habitat suitability usually decreases with distance Longer: but suitability could be incredibly ideal and competition reduced in far places like islands!
89
Types of dispersal
Active (vagility) Passive (pagilitiy)
90
Phoresy
animals hitchhiking on others
91
Zoochory, Anemochory, hydrochory...
Passive dispersal of propagules via different things
92
How does range expansion decrease risk of extinction
How does range expansion decrease risk of extinction
93
Diffusion (think CAEG)
Slow: generations (iterative steps) Rapid: founder events free of competition & disease; human mediated many times
94
Secular Migration Dispersal
Gradual (thousands to millions of years) coupled with evolutionary change; think camelids
95
Long distance jump dispersal
fast: individuals travel great distances; rare
96
Barriers to dispersal
Species-specific Niche-breadth (Janzen) Physiological (Severe) Ecological
97
What is phyletic extinction?
species disappears due to evolutionary change in lineage
98
What causes local extinction?
Climate Change (habitat, disease, acidification) Disturbance/natural disasters Invasion by exotics Humans Stochastic fluctuations
99
Explain relationships of demography and extinction
Smaller pop = stochastic extinction Nonlinear relationship; small pops high risk, but birth > death dramatically, grow quickly
100
Why is abundance higher at center of ranges?
- Habitat suitability (fundamental niche constraint) -resource/mutualists/antagonists (realized niche constraints) - duration of occupancy (abundance reflects how long lived there)
101
Explain immigration and chance for adaptation
Source pop can swamp out sink/edges if immigration is high, inhibiting adaptation
102
What is species richness?
the number of species in a community
103
Different types of diversity
Alpha: species richness single subunit Gamma: Species richness of entire region Beta: Turnover across units; the change in composition between! not the immigration
104
What is phylogenetic diversity?
Independent + shared evolutionary history!
105
What causes high vs low phylogenetic diversity?
High: competition (close relatives ecologically similar) Low: environmental filtering (physiological tolerances of local conditions require adaptations that evolve rarely and are conserved)
106
Functional Diversity
Measure diversity of ways which species influence ecosystem function - measure functional traits
107
patterns of functional diversity, phylogenetic diversity, and species richness
they generally correlate; lineages diverge and more traits are different
108
Where are patterns of phylogenetic and functional diversity disparate?
Tropics! -> the mismatch shows LOW functional diversity relative to the phylogenetic diversity; opposite for temperate regions higher latitude
109
Tropical Diversity variable vs temperate uniformity
Environmental conditions are harsh in temperate; poles are severe, tropics suggest no one mechanism determines the richness
110
Why are some taxa more diverse outside tropics?
They may have overcome temperate issues = key innovation & are free of the restraints, so can speciate
111
What are parameters that control the latitudinal gradient?
Origination, Extinction, Immigration
112
Cradle vs Museum vs Out of Tropics
Cradle: Origination in tropics high Museum: extinction greater in temperate Out of Tropics: Origination higher in T, Extinction lower in T, Immigration out of tropics higher
113
As opposed to parameters that control, what are the drivers of the latitudinal gradient?
Geographic area and time Available Energy Climate Stability Biotic Interactions
114
How do area and time contribute to the latitudinal gradient?
Area: bigger area has more barriers, heterogeneity -> increases range size Time: allows processes to proceed for longer time = affect accumulates = Speciation
115
How does time-integrated area explain modern patterns?
Tropical areas have been around for longer, so longer time for speciation
116
How has climate stability been a part of the latitudinal gradient?
it is more stable at equator; broader tolerances at poles (like seasonality); stability favors specialization (less extinction, longer time)
117
How do biotic interactions drive the latitudinal gradient?
Biotic interactions are more prevalent in the tropics; but haven't been tested really; specialize; Diversity begets diversity
118
What is diversity begets diversity?
Stable environments = arms race between pathogens & hosts, predator prey etc -> accelerate speciation
119
What is the "Janzen-Connell hypothesis"? How does this hypothesis purport to explain high diversity of trees in tropical forests?
Overcompensating negatice density-dependent mortality; aka, pathogens and predators kill things that are close together, so more diverse low density species better; rare species advantage
120
How does energy drive the latitudinal gradient?
(Metabolic) Thermal Kinetic Hypothesis: higher temp = higher metabolic rate = more evolution (higher speciation rate) (Productivity) Chemical Potential Energy Hypothesis: more primary production = more plants = more animals = lower extinction rate
121
However, speciation and extinction are found to be faster outside the tropics. Does this support metabolic or productivity hypotheses?
Contrary to Metabolic; shallower divergence times in birds outside tropics
122
What is the null model of richness? How does this also contribute to the latitudinal gradient?
Mid-domain effect from geometric constraint - if you randomly distribute ranges across a gradient with hard bounds, more ranges and larger ranges fall towards the middle
123
So, why are there more species in the tropics?
Time-integrated area (speciation) Climatic Stability (persistence) Tropical Niche Conservatism (speciation, movement) Biotic interactions (janzen-connell, diversity begets...) Energy and productivity (rate of evolution)
124
What is humbold's enigma?
High species richness in mountains not explained; even outside tropics; 25% land area but 85% of a lot of animals Species richness and temp + precip = predict tropics, but not mountains
125
Who was Alexander von Humboldt?
German rich naturalist who went around the globe pre-Darwin. He wasnt a jerk which was cool; coordinated global research!
126
What are potential drivers of richness across elevation?
Area: Elevational band area decreases towards peak; mid-domain effect Climate: gradients of climate on mountains (esp higher latitudes constraint; arid and cold) Biotic Interactions (red queen, begets)
127
What about topographic diversity pattern?
Higher complexity = more species; while stability promotes persistence, dynamic nature of mountain formation also accelerates diversification
128
Explain how mountain formation may drive speciation
Orogeny: mountains build and erode; species move up and are pushed down Glacial Cycles: valleys separate & speciation; glaciers push down into contact; character displacement or adaptive introgression

Biogeography (2 decks)

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