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29 Cards in this Set
- Front
- Back
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biogeography |
distribution of species , more vs less , quantifying patterns understanding these patterns |
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how to map biogeography |
survey , and map species field data how do we measure geographic range of species from this data Use GIS, there is no perfect way to map species range= can be mapped as polygon we are interpolating from data range is actually 3D |
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range size distributions |
tails out from large to really small majority of species have small geographic ranges mechanisms restricting area is not known Reasons: Climate, speciation(young species not as spread out)/ local extinction, habitat specialization, phyical intolerances , |
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ranges can change over time |
european starling, habitat spread over many years, range spread Range contraction , Grizzly bear , habitat spread from Mexico, now it has contracted more north driven by extinction |
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Functions of physical and biotic factors of range limits Physical |
barriers to dispersal, mountains , coast, RIVER temperature, physiological limits, seasonality , cannot live in high fluctuation of seasons from winter to summer precipitation, rain fall patterns salinity ocean currents: larvae traveling |
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Functions of physical and biotic factors of range limits habitats |
absence of suitable habitat |
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Functions of physical and biotic factors of range limits biotic |
biotic interactions competiton: 2 closely related species, ranges do not overlapp, one species is ahead predation: whatever constrains the distribution of prey constrains distribution of predator mutualisms: plants and pollinators: constrained by distribution of plants. zooxanthellae constrained by coral |
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Functions of physical and biotic factors of range limits adaptation and gene flow |
Most not all species , is in a given area, individuals spread to new areas, most common towards center of distribution ranges. Called Abundant Center Hypothesis individuals form new populations outside of center , they become locally adapted constaint, gene flow from center to outside, gene flow will try to push boundary towards center , collaspe inward. determines range boundary |
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Endemism |
species occuring nowhere else, can have large or small geographic area. endemic to continent or region 2 ways: originate in a place and never disperse or range collapse , grizzly |
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Cosmopolitanism |
widely dsitrbuted across planet few species are cosmopolitan human introduction are making species cosmopolitan, deliberate or accidental many families and genera Biotic Homogenization: this may be good or bad |
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distribution |
species and higher taxa are not distributed randomly. provinces= distinct region with unique fauna boundary provinces are sharp |
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how many species can you fit into an area |
species- area relationship S= cA^z s= # of species A=area c= constant z= fitted parameter number of species in an area is dependent ojn the sizes and fitted parameters |
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species area relationship |
are scale dependent larger area more species, |
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theory of island biography |
1 factor, area habitat islands, or oceanic x-axis= # of species y-axis = rate of immigration or extinction immigration rates high early on in islands as more and more come, rate of immigration goes down due to crowding. as the island gets crowded rate of extinction goes up , due to competition. The Number of species we see at a point in time, reflects equilibrium between immigration and extinction rates |
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main points theory of islands |
# of species increases with size and decreases with with isolation continous turnover of species , not static Assumptions : not true , biota are in equlibrium: not true immigrationa and extinction are independent no speciation on island: not true |
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diversity at different geographic scales |
alpha diversity , smallscale, = # of species in a sample medium scale , beta diversity = extra species gain in multiple sample combined , measure of turnover higher beta means high turnover , low beta means same species in 2 areas gamma diversity , large scale = all species present in a region or in all samples |
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relationship between local- regional diversity |
how are alpha and gamma related? 3 possibilities 1 to 1 type 1 = as regional richness goes up so does local rich but not at same rate, regional factors determine species richness, no local saturation, seen most often , type 2 = as regional goes up local flatlines but asymptotes , high beta, community is saturated, local factors control species richness |
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macroecology |
LARGE SCALE ecological patterns understand major biodiversity patterns species richness , abundance, on global scale quantify statistical patterns comparative, non-experimental a bridge from small to large scale patterns |
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Latitudinal Diversity Gradient |
species richness decreases from equator to poles both marine and terrestrial few species reserve trend gradient is not symmetrical / uniform |
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why are there more species in tropics ? |
still poorly understood ecological and volutionary |
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gradient trend ecological density- dependent mortality |
specific for plants. as density goes up , less recruitment of seedling slope is less than one if rare , seedling recruitment goes up , seedling recruitment is negatively density dependent. high species density= lower density it allows more species to coexist locally, prevents 1 species from taking over mortality , may be due to specialized predator or pathogen MAy explain LDG, at higher latitudes if seedling recruitment is not negatively dependent, there are less species coexisting |
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Species-Energy Hypothesis |
tropical areas are warmer, more solar energy |
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converting energy to diversity |
more energy supports more biomass, more individuals, more species PROBLEMS for plants more energy means get bigger not more individuals |
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Evolutionary explanation of LDG |
age and climatic stability of tropics tropics have been around longer, more stable, biggest change in climate has been in higher latitudes Changes in rates of speciation |
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Changes in rates if speciation and or extinction or both with latitude Cradle or Museum |
1. tropics is a cradle , generates high speciation rate 2. tropics is museum, extinction rate is really slow, species accumulation is high missing spatial dynamic |
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Out OF the Tropics theory |
tropics have high origination and low extinction rates things spread out over time. towards higher latitudes immigration is from tropics to outside |
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Body Size Distributions macro ecology |
there are more individuals from smaller species than larger ones - most species are small -but smallest size is not the most common -modal size is about 100 grams for mammals |
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Size Frequency Distributions |
sizes are set by fundtional and physiological constraints - smaller preferred but not the smallest - distribution of sizes controlled energy , fractal habitat (point of view) ` |
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Energetic Model of Body Size |
kw |
