Week 2 Part 1 Flashcards
What is Biogeography
The study of patterns of species composition and diversity across geographic locations
What determines community composition
Local scales -abiotic factors and species interacations
Broader scales- regional processes
What is the hierachy of spatial scale
Global
Regional
Landscape
Local
What is the global scale
THe entire world species have been isolated from one another on different continents or different oceans by long distances and over long periods
What determines species diversity and composition
Speciation
Extinction
Dispersal
What is the regional scale
Areas with uniform climate the species are bound by dispersal to that region
Provides the raw material for local assmeblys and sets theoretical upper limit on species diversity for communities
What is the regional species pool
What diversity
All the species contained within a region (gamma diversity)
What is landscape scale
Topographic and environemental feature fo a region
Species composition and diversity vary within a region depending on how the lanscape shapes rates of migration and exctions
Defined by moutanins lakes or froests
What is local scale
Equlivalent to a community
Local species diversity (alpha diversity) determined by species physiology and intercation with other species
What is beta diversity
Change in species numbers and composition or turnover from one community type to another conncect local and regional scales
What are global patterns and species diversity and composition controlled by
Geographic area and isolation historical factors and global climate
Who is the father for biogeography and what did he discover
Alfred Russel Wallace
There is a gradient of species diversity with latitude (with more species at the equator than towards the poles)
How many biogeographic regions can earths land mass be divided into and what are they
6
Neartic
Neo-tropical
Ethiopian
Paleratic
Australasian
Oriental
What were the different contient formations
Permian period pangaea
Cretaceous period laurassia and gondwana
Early tertiaray period
Are north and south america similar
they are more different thatn you expect because of there proximity but south america and australia are more similar than youd expect
What is vicariance
Evolutionary separation of species by barriers such as those formed by continental drift
What is an example of vicariance
Large flightless birds had a common ancestor from Gondwana. After isolation on different continents they evolved unique characteristics but retained their large size and inability to fly. South america, africa and australia all have ratties but Laurasian continents do not
What are global patterns of species richness controlled by
Speciation, extinction dispersal
What is species diversification rate
The net increase or decrease of species over time
Which latitude has many more species than
Lower latitudes have more species than higher latitudes
What does the diversification time show
Diversify at the same rate add species at the same time they existed longer in temporal ice age there was nothing
More stable over time and have had more time to evolve
What does the productivity or carrying capacity
There is more resources so higher productivity and higher maximum higher productivity leads to lower extinction rates, greater coexistence and overall higher species richness
What is the species diversification rate
The tropics have many niches into which species can diversify thermally stable decrease extinction
What can the tropics could be seen as
Cradle of diversity many new species are borth there but also a museum species that diversify there tend to stay there
What could the loss of biodiversity in the tropics do
Cut off the supply of new species to higher latitudes in the future
What are regional differens influnced by
Area and distance which determines the balance between immigration and extinctionr ate
What is the species area relationship
Species richness increases with area sampled
What is the species are curve equation
S =zA + c (z is slope, c= yintercept
What does island species diversity show
A strong negative relationship to distance from a source of species so the closer to the mainland more species
What is the equilibrium theory
Mcarthur and Wilson
States the number of species on an island depends on a balance between immigration or dispersal rates and extinction rates
Where should the number of species on the island should fall
The two curves intersect between immigration and extinciton the number of species that should fit on the island regardless of the turnover
