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Many groups; extinctions largely the result of human activities.
Current extinction.
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Which extinction are we on?
6th
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This extinction was reptiles (dinos); many marines species, including many foraminiferans and molluscs.
Cretaceous
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This extinction 25% of animal families, including many reptiles and marine molluscs. 180 millions years
Triassic
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This extinction 250 million years. 50% of all animal families, including over 95% of marine species; many trees, amphibians, most bryozoan and brachiopods, all trilobites.
Permian
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This extinction took place 345 years ago. 30% of animal families, including Agnatha and placoderm fishes and any trilobites.
Devonian
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This extinction took place 500mill years ago. 50% of animal families, including many trilobites.
Ordovician
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The number of species on an island can be predicted from the islands?
Area
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This model describes the relationship between the rates of colonization and extinction is islands.
The island biogeography model.
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According to the island biography model, the number of species present in an area does what?
Increases asymptotically
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Is the effective population Ne approaches 1 what happens with the genetic variations?
If the genes are all the same then the variation plummets.
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Effective population size.
Ne
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Effective population size males.
Nem
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Effective population size females.
Nef
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Unequal sex ratios formula for real population size.
Ne =(4NmNf)/(Nm+Nf)
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What is the Harmonic mean?
Multiple generations with available Ne. G1 100 G2 100 G3 100 G 4 10 etc.
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How do you calculate the Harmonic mean?
Ne= t/(1/N1 + 1/N2 …. 1/Nt)
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One a population drops below a certain size, it enters an extinction vortex in which factors that affect small populations tend to drive sits size ………
Progressively lower.
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When population size is infinite.
HW
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What is the formula when H= heterozygous
(1 – 1/Ne)Ht
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Name a bunch of things that will lead to extinction?
Environmental stochasticity, catastrophic events, Habitate distraction, environmental degradation, habitat fragmentation, overharvesting, effects of exotic species, disease, and climate change.
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Agricultural ecosystems, forestry activities, and industries are usually valued by?
The products they produce
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Wealthy countries with higher gross domestic product (GDP)per person tend to have higher?
Environmental Performace Index scores (EPI)
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Although many grassland systems are adapted to grazing, overgrazing reduces ecosystem services and can lead to?
Decreased ecosystem productivity and increased soil erosion,
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As plant coverage increases on the prairie what happens to the ecosystems?
They become more diverse
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Bees provide ecosystems for humans by?
Pollinating food crops
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Ecotourism can provide an economic justification for protecting
Biodiversity
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What are the three use values?
Direct, Indirect, and Option
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What are slime examples for direct use values?
Food and fuel.
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What are some examples of indirect use values?
Flood controls, tourism, education, pollution control.
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What are some option use values?
Future products: Meds, food coursed, building supplies, genetic resources.
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This act was brought to light due to putting existence value to things, weakened due to consequences, and based on data.
Endangered species act.
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Is one of the most comprehensive biological surveys in the world.
The North American Bird Survey (BBS)
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What kind of analysis is needed to predict how much habitat is needed to ensure 95% of the species to survive?
Population Viability analysis.
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What kind of population size is needed to the perisistence of a species for as long a s possible minimally?
Minimal Viable population size
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When comparing small herbivores, larger herbivores, and large carnivores, what is the scale for land that is needed?
SH, LH, LC. Carnivores need more habitat space
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