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
Q

What were the tectonics and climate of the Pliocene?

A

5.3 - 2.58 MA
- Climate warmer, sea levels higher
- Climatic oscillations
- Arctic Ice Cap
- GABI!
- Homo

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26
Q

What were the tectonics and climate of the Quaternary?

A

2.58 - 0 MA
Glacial-Interglacial Cycles
- Milankovitch Cycles drive these cycles

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27
Q

What feedback effects occur during milankovitch cycles?

A
  • Albedo (from ice extent), changes in CO2 with plant productivity
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27
Q

Explain the Milankovitch Cycles

A

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.

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28
Q

What is geographic range?

A

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

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29
Q

What is an irruption?

A

Movement in years of resource change

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30
Q

Why is range tricky regarding the concept of species?

A

Because defining a species is tough! Range is an emergent property (group thing), so you have to decide what the group is

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31
Q

What is the basis of range? Specifically, the “atomic basis”

A

Record of occurrence (like photo, museum specimen, etc)
- Surveys, Community Science, inventories, museums

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32
Q

What are the types of maps?

A

Dot
Outline
Contour
Predictive

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33
Q

What are dot maps?

A

Precise locations; biased; fixed in time

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34
Q

What are outline maps?

A

Informed subjective estimate of occurrence -> occurrence, geography, climate, ecosystem, physiology included in the making

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35
Q

What are Contour Maps?

A

Maps of abundance; hard to do unless a lot of sampling; interpolation required

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36
Q

What are predictive maps?

A

Species distribution models -> correlate occurrence with environmental variables and predicts suitable habitat areas

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37
Q

What are some problems and considerations for making range maps?

A
  • Quality of data inconsistent; sampling bias (roads)
  • Core range vs outliers
  • Native vs invasive ranges
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38
Q

What is a Wallacean Shortfall?

A

For most species we know very little about range, esp. thru time.

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39
Q

What are the 2 quantities for measuring geographic range? Measuring is important for comparison!

A
  1. Extent of Occurrence (along a dimension; distance, latitude, elevation)
  2. Area of Occupancy (2D; ellipse, hull, area over grid)
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40
Q

What questions can be answered with comparing the extent of occupancy of a species?

A
  • Ecological niche relationship
  • Extinction Risk
  • Gene Flow
  • Dispersal Ability
  • Phenotypic Plasticity
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41
Q

What are ways to measure area of occupancy?

A

Ellipse
Convex Hull
Grid Cells

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42
Q

What is Spatial Dispersion? What are the patterns?

A
  • Distribution of points (organisms)
  • Clumped, Random, Even
    SCALE-DEPENDENT
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43
Q

What is important about cells and grids for area of occupancy?

A

It is SCALE-DEPENDENT! Think about the spatial dispersion

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44
Q

What size are most ranges?

A

Small!

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45
Q

What is something that determines range sizes?

A

Body Size (constraint against large body and small range)

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46
Q

What is Rapoport’s Rule?

A

Range increases with latitude (and elevation, sea depth)

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47
Q

Why are ranges bigger at higher latitudes and elevations?

A

Physiological limits (fitness)

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48
Q

What is Hutchinson’s Niche Concept

A

Curve over all relevant aces of variation -> n-dimensional hypervolume = Fundamental Niche!

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49
Q

What did Janzen say about mountains and what is the reasoning?

A

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

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50
Q

What is the fundamental niche?

A

the full range of environmental conditions under which an organism can live

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51
Q

Give an example of range limited by physiological requirements

A

Plants - like Saguaro Cacti - ranging to the frost zone (die from cavitation and prolonged freezing)

52
Q

What limits geographic range?

A

abiotic factors (temp, soil moisture, elevation), dispersal ability, disturbance (fire) and biotic factors (predation, competition, parasitism)

53
Q

What is the realized niche?

A

where and how a species is actually living; the combination of realized environment and fundamental niche limited by abiotic and biotic factors

54
Q

What is competitive exclusion?

A

the inevitable elimination from a habitat of one of two different species with identical needs for resources.

55
Q

What is parapatric competitive exclusion?

A

When ranges are adjacent (not overlapping) of incredibly similar species, suggesting competitive exclusion processes

56
Q

What is Gause’s Law

A

Species competing for the same limited resource cannot stably coexist

57
Q

What is an example of natural experiments of competitive exclusion?

A

Local absences show competitors respond to absence of competition

58
Q

Explain the barnacles thing

A
  • too high and they desiccate
  • too low and they compete
  • the lower ones kept at bay with the snails
59
Q

What is Dobzhansky-MacArthur Phenomenon?

A

Poleward range limited by physiological constraints and equatorial range enforced by biotic factors

60
Q

What are equilibrial limits? These are things other than niche that determine range size

A

Independent of time; geometric constraint, habitat availability, climatic variability, dispersal, body size, mating system

61
Q

What are some non-equilibrial limits to range size? What are patterns of this?

A

Dispersal Barrier changes (GABI, post-glacial migration_
Patterns: Stasis, idiosyncratic, age-and-area, stasis post expansion, species age

62
Q

Explain Time for Dispersal vs Time for Adaptation

A
  • 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
Q

What is species distribution modeling?

A

Mapping the fundamental niche; combines occurrence with environmental variables and predict suitability

64
Q

Steps to do SDM

A
  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
Q

Does SDM truly estimate the fundamental niche?

A

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
Q

Buffon’s Law

A

Isolated regions with similar climates have distinct species assemblages

67
Q

What is phylogeny?

A

Ancestor-descendant relationships based on genetic information; genes & populations & lineages

68
Q

Tokogenetic:

A

Ancestor-descendant relationships of individuals

69
Q

Phylogenetic

A

Ancestor-descendant relationship of populations/species

70
Q

Evolutionary species concept

A

species: organisms that maintain identity from others; independent evolutionary fate and historical tendencies

71
Q

What things do species concepts emphasize?

A

Relatedness (history) or Ecology

72
Q

What is relatedness in species concepts?

A
  • Exclusive groups more closely related to each other than outsiders
  • phylogenetic species concepts (monophyly)
  • looks at the past
73
Q

What role is ecology used for in species concepts?

A
  • Distinct ecological niches
  • reproductive isolation
  • biological, ecological, trait-based concepts
  • predict future
74
Q

What goes into geographic models of speciation?

A

Range expansion + genetic/ecological differentiation - gene flow (think mountains)

75
Q

What is a ring species?

A

Interbreeding between adjacent pops, but terminal pops cannot interbreed

76
Q

What is Dobzhansky-Muller incompatibility?

A

genetic isolation
negative epistasis; geographic isolation & mutations; secondary contact doesnt allow for hybrid

77
Q

What is allopatric speciation? Can it be ecological? What about not?

A

geographic isolation which results in speciation; yes can be both ecological and nonecological

78
Q

What does sympatric speciation require?

A

ecological differentiation (or chromosome stuff - polyploidy)

79
Q

Vicariance vs Founder Event

A

Vicariance: mountains; population split, no huge Ne change

Founder/peripheral: tiny founder population; diversity reduced

80
Q

What does secondary contact do after allopatric divergence?

A

It can drive character displacement! -> no stable coexistence in sympatry with niche stuff

81
Q

Radiation

A

Speciation events in rapid succession in a clade

82
Q

Adaptive Radiation

A

speciaton event = ecological!; or nonecological followed by ecological differentiation; can be sympatric

83
Q

Nonadaptive Radiation

A

Nonecological speciation; descendants are allopatric or parapatric from competitive exclusion

84
Q

Modes of range evolution

A

Dispersal (expansion)

Local Extinction (contraction)

Speciation

85
Q

What is dispersal?

A

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
Q

What ISNT dispersal?

A

Migration (seasonal ranges)
Nomadism (irregular response to resource)
Vagrancy (unpredictable few individuals; hurricanes)

87
Q

Why disperse?

A
  • reduce competition
  • increase fitness in higher quality enviros
  • reduce risk of extinction
88
Q

When might selection favor shorter vs longer dispersal?

A

Shorter: habitat suitability usually decreases with distance

Longer: but suitability could be incredibly ideal and competition reduced in far places like islands!

89
Q

Types of dispersal

A

Active (vagility)
Passive (pagilitiy)

90
Q

Phoresy

A

animals hitchhiking on others

91
Q

Zoochory, Anemochory, hydrochory…

A

Passive dispersal of propagules via different things

92
Q

How does range expansion decrease risk of extinction

A

How does range expansion decrease risk of extinction

93
Q

Diffusion (think CAEG)

A

Slow: generations (iterative steps)
Rapid: founder events free of competition & disease; human mediated many times

94
Q

Secular Migration Dispersal

A

Gradual (thousands to millions of years) coupled with evolutionary change; think camelids

95
Q

Long distance jump dispersal

A

fast: individuals travel great distances; rare

96
Q

Barriers to dispersal

A

Species-specific
Niche-breadth (Janzen)
Physiological (Severe)
Ecological

97
Q

What is phyletic extinction?

A

species disappears due to evolutionary change in lineage

98
Q

What causes local extinction?

A

Climate Change (habitat, disease, acidification)
Disturbance/natural disasters
Invasion by exotics
Humans
Stochastic fluctuations

99
Q

Explain relationships of demography and extinction

A

Smaller pop = stochastic extinction

Nonlinear relationship; small pops high risk, but birth > death dramatically, grow quickly

100
Q

Why is abundance higher at center of ranges?

A
  • Habitat suitability (fundamental niche constraint)
    -resource/mutualists/antagonists (realized niche constraints)
  • duration of occupancy (abundance reflects how long lived there)
101
Q

Explain immigration and chance for adaptation

A

Source pop can swamp out sink/edges if immigration is high, inhibiting adaptation

102
Q

What is species richness?

A

the number of species in a community

103
Q

Different types of diversity

A

Alpha: species richness single subunit
Gamma: Species richness of entire region
Beta: Turnover across units; the change in composition between! not the immigration

104
Q

What is phylogenetic diversity?

A

Independent + shared evolutionary history!

105
Q

What causes high vs low phylogenetic diversity?

A

High: competition (close relatives ecologically similar)

Low: environmental filtering (physiological tolerances of local conditions require adaptations that evolve rarely and are conserved)

106
Q

Functional Diversity

A

Measure diversity of ways which species influence ecosystem function

  • measure functional traits
107
Q

patterns of functional diversity, phylogenetic diversity, and species richness

A

they generally correlate; lineages diverge and more traits are different

108
Q

Where are patterns of phylogenetic and functional diversity disparate?

A

Tropics! -> the mismatch shows LOW functional diversity relative to the phylogenetic diversity; opposite for temperate regions higher latitude

109
Q

Tropical Diversity variable vs temperate uniformity

A

Environmental conditions are harsh in temperate; poles are severe, tropics suggest no one mechanism determines the richness

110
Q

Why are some taxa more diverse outside tropics?

A

They may have overcome temperate issues = key innovation & are free of the restraints, so can speciate

111
Q

What are parameters that control the latitudinal gradient?

A

Origination, Extinction, Immigration

112
Q

Cradle vs Museum vs Out of Tropics

A

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
Q

As opposed to parameters that control, what are the drivers of the latitudinal gradient?

A

Geographic area and time
Available Energy
Climate Stability
Biotic Interactions

114
Q

How do area and time contribute to the latitudinal gradient?

A

Area: bigger area has more barriers, heterogeneity -> increases range size
Time: allows processes to proceed for longer time = affect accumulates = Speciation

115
Q

How does time-integrated area explain modern patterns?

A

Tropical areas have been around for longer, so longer time for speciation

116
Q

How has climate stability been a part of the latitudinal gradient?

A

it is more stable at equator; broader tolerances at poles (like seasonality); stability favors specialization (less extinction, longer time)

117
Q

How do biotic interactions drive the latitudinal gradient?

A

Biotic interactions are more prevalent in the tropics; but haven’t been tested really; specialize; Diversity begets diversity

118
Q

What is diversity begets diversity?

A

Stable environments = arms race between pathogens & hosts, predator prey etc -> accelerate speciation

119
Q

What is the “Janzen-Connell hypothesis”? How does this hypothesis purport to explain high diversity of trees in tropical forests?

A

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
Q

How does energy drive the latitudinal gradient?

A

(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
Q

However, speciation and extinction are found to be faster outside the tropics. Does this support metabolic or productivity hypotheses?

A

Contrary to Metabolic; shallower divergence times in birds outside tropics

122
Q

What is the null model of richness? How does this also contribute to the latitudinal gradient?

A

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
Q

So, why are there more species in the tropics?

A

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
Q

What is humbold’s enigma?

A

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
Q

Who was Alexander von Humboldt?

A

German rich naturalist who went around the globe pre-Darwin. He wasnt a jerk which was cool; coordinated global research!

126
Q

What are potential drivers of richness across elevation?

A

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
Q

What about topographic diversity pattern?

A

Higher complexity = more species; while stability promotes persistence, dynamic nature of mountain formation also accelerates diversification

128
Q

Explain how mountain formation may drive speciation

A

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