t09 biogeography wrksht.ppt - clark university€¦ · 8/19/2013 1 how would these distributions...
TRANSCRIPT
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Topic 9: Biogeography
� What is biogeography?
� What are the different disciplines of biogeography?
� What are important concepts in biogeography?
� Herpetological examples
What is biogeography?
� Study of past and present ___________, ___________ and _______ of organisms
� Based on premise that history of _______ and _____________ are interconnected
� Addressing why organisms have the patterns of distribution that they have
What is biogeography?
Biogeographic
Distribution
HistoryEcology
Organism Environment Vicariance Dispersal
Phylogeny
All of these nested factors influence the distribution and abundance
of organisms, either directly or indirectly
What are the four disciplines of biogeography?
� __________ biogeography
� __________ biogeography
� __________ biogeography
� _____________________
� Each of these focuses on different factors that influence distribution and abundance
� Each has something to say about why Amphisbaenidae are distributed
Pough et al. 2004, Fig. 4-22
� ___________ biogeography� How distributions have
been shaped by organismal biology
� ___________ biogeography� How presence/absence and
diversity are determined on islands
� ___________ biogeography� How distributions have
been shaped by the Earth’s history
� Phylogeography� Next lecture
� Important considerations when studying frog distributions� Pipidae� Pelobatidae� Megophrydae
Pough et al. 2004, Fig. 3-27
What are the four disciplines of biogeography?
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� How would these distributions have come about?
Pough et al. 2004, Fig. 3-27Pough et al. 2004, Fig. 4-22
Amphisbaenidae
Pipidae MegophrydaePelobatidae
What are the four disciplines of biogeography?
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Ecological biogeography - Concepts
� How distributions have been shaped by organismal biology
� Physiological tolerances
� _______________ biology
� Moisture
� _______________
� Altitude
� ______________________
Miller 2003, Ricklefs 2000
Ecological biogeography - Concepts
� Agreeable places for a species to live can change through time
� Long term
� ___________
� ___________
� Short term
� ______________
� ______________
Ecological biogeography - Concepts
� How distributions have been shaped by organismal biology
� Niche characteristics
� __________________
� Terrestrial
� __________________
� Aquatic
� __________________
Powell and Russell, 1992
© J. Losos
© Auburn
Herp Soc
Twig giant
Crown giant
Trunk-crown
Trunk-crown dwarf
Trunk-ground© Reptilien-
Center.de
© KP Bergmann
Ecological biogeography - Example
� Interspecific competition
� Availability of niches
� Availability of resources
Duellman & Pianka, 1990
� Geckos & frogs fill similar niches
� Both are mainly nocturnal
� Diverse in the tropics
Thecadactylus
Ecological biogeography - Example
� Pattern is pronounced all over the world
Duellman & Pianka, 1990
� Geckos & frogs fill similar niches
� Both feed on small insects
Ecological biogeography - Example
� _______________
� Some species are better than others
� Leathery vs. hard eggs
� Starvation resistance
� Some move further than others
� Chance…
Censky et al. 1998; Photos PJB, KP Bergmann
Iguana iguana
introduced to Anguilla by
hurricane
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Ecological biogeography - Example
� Elevational distributions of hylid frogs in Oaxaca
� Considerable ________________ changes with __________
� Most diverse at mid-elevation
Pough et al. 2004, Fig 5-20
� Pond breeders at low elevations
� Stream breeders at mid-elevations
� Bromeliads used on Atlantic slopes – more moist
Island biogeography - Concepts
� How presence/absence and diversity are determined on islands
� Important island factors
� _______________________
� Proximity to _____________
� Important processes
� _____________
� _____________
Photo © PJB
Island biogeography - Concepts
� Important island factors
� Size
� Proximity to mainland
� Important processes
� Immigration
� Extinction
� # of Species
� ______________ with increased island area
� ______________ with increased distance from mainland
Government of Canada
Island biogeography - Concepts
� Important island factors� Size� Proximity to mainland
� Important processes� Immigration� Extinction
� With increased # of species� _____________ decreases� _____________ increases
� Results in equilibrium
� Large, near islands have� __________ extinction rate� ________ immigration rate� __________species
# of SpeciesRate of Immigration/Extinction
Equilibrium
I ENear
SmallNearNearNear
SmallSmallSmall
Equilibrium
I EI E
# of Species
I E
Rate of Immigration/Extinction
# of Species
I E
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Island biogeography
- Example
� Isolation by distance
� Faunal similarity
� Closer islands have more species in common
� Differences between frogs and snakes
� ____________________
� ____________________
� ____________________
� Ecological biogeography is also important…
Pough et al. 2004, Fig. 5-13
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Island biogeography
� Not all islands are surrounded by water!
� Island biogeography applies to suitable patches of habitat
� Habitat surrounded by obstacles/”bad” habitat
� Examples:
� Reefs
� __________________
� Oases of various kinds
� __________________
© J Palkiewicz; www.birddigiscoper.com
Historical biogeography - Concepts
� How distributions have been shaped by the Earth’s history
� Changes in ___________
� Changes in ______________
� _________________
Pough et al. 2004, Fig 5-3b
• Much of Mesozoic (251-65 mya)
• Forested•Warm
•Home to many animals
including reptiles
Antarctica’s climate has
changed considerably over
millions of years
Historical biogeography - Concepts
� Changes in sea level
Pough et al. 2004, Fig 5-12
• Land masses become connected…
•…or they become disconnected
Historical biogeography - Concepts
� ___________________
� Fundamental force behind many changes
� Huge driver of biogeographic patterns
� The continents move!!!
Campbell 1993
� Continents are on tectonic plates
� Compose the crust
� Float on the mantle
� Spread apart
� Collide
Historical biogeography - Concepts
Zug et al. 2001, Fig 13.15
� Pangea �
� Laurasia
� Nearctic
� Palearctic
� Oriental*
� Gondwana
� Neotropical
� Ethiopian
� Australian
� Oriental*
Historical biogeography - Concepts
� _____________ & ____________
� Two major mechanisms behind patterns of distribution
� Competing theories
� Both clearly important
� Much past controversy
Pough et al. 2004, Fig 5-1b
T1
T2
T3
Vicariance
Vicariance
Dispersal
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Historical biogeography - Concepts
� _______________� The separation of a group
of organisms by a geographic ____________
� A barrier becomes erected, splitting a population
� Separated populations __________________
� Many possible vicariant agents:
� Plate tectonics
� ___________________� Rivers changing course� ___________________
� Canyon building, etc.
© Google, PJB
Historical biogeography - Concepts
� Vicariance
� Example: Distribution of the Amphisbaenidae
� Multiple vicariant events giving modern distribution
Pough et al. 2004, Fig 4-22
1. Break up of ____________
2. Eastern movement of
____________ plate
3. Drying of _____
_____________
Historical biogeography - Concepts
� _____________
� The permanent movement of organisms from one geographic location to another
� Hard to test for, but clearly important
� Many dispersal agents:
� Some organisms move
� ____________________
� Ocean currents & rivers
� ____________________
� Humans
Censky et al. 1998
Historical biogeography - Concepts
� “Lizards took Express Trail to Polynesia”
� Lipinia noctua (Scincidae)
� Low mtDNA divergence among Polynesian populations
� __________-mediated dispersal
Austin, 1999
Historical biogeography - Concepts
� Dispersal is only way that anything gets on __________ islands…
� Galapagos, Hawaii, Lesser Antilles, Krakatoa (natural experiment)
� Ocean currents can play a big role
� Also dispersal ability of organisms
Pough et al. 2004, Fig 5-11
Historical biogeography - Example
� The Caribbean has a complex history
Pough et al. 2004, Fig 5-5
� Heated debate about roles of vicariance and dispersal
� Only when V is disproven, can you suggest D?
� How might we distinguish V & D?
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Historical biogeography - Example� Look at timing of phylogenetic
divergences
� Dated divergences between species on different landmasses
Hedges et al. 1992
� Distinct times when vicariance possible, otherwise dispersal
� Anolis, Eleutherodactylus,
Sphaerodactylus
Historical biogeography - Example
� Explaining a disjunct distribution pattern
� South America + Madagascar, but not Africa
Noonan & Chippindale 2006
� Malagasy Oplurinae are nested within the New World Iguanidae
� Why aren’t Iguanids in Africa?
Historical biogeography - Example
� Explaining a disjunct distribution pattern
� South America + Madagascar, but not Africa
Noonan & Chippindale 2006
Similar pattern in:
• Boinae
• Podocnemidae
Historical biogeography - Example
� Madagascar was more closely associated with ____________________ (and India) than Africa
� Not complete picture
� Why aren’t these herps in India?
� Fossil Boid Madtsoia has been found all over Gondwana
� Perhaps climate change and competition played a role
Noonan & Chippindale 2006
Historical biogeography - Example
� Climate: Africa has undergone considerable drying, but there are still wet areas, without these animals
� Competition: Ecologically analogous taxa exist
Pough et al. 2004, Fig 4-18
� “Agamidae” and Pythoninae have similar ranges �
� Origin in SE Asia with dispersal into Africa & Australia…
“Agamidae”