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Con Bio Lecture 5 - Extinction
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- 1What are the 5 Past Mass Extinctions?Oldest - most recent:
- Ordovician
- Devonian
- Permian (largest)
- Jurassic
- Cretaceous (dinosaurs) - 24 things island species have- limited range areas
- small pop sizes
- small numbers of pops
- limited predators, competitors, diseases - 3Island Biogeography ModelBy MacArthur and Wilson, 1967
- for estimating future extinction rates
- species area relation
- larger island = more species
- S=CA^z (s = species, A = area)
- small island far from mainland = lowest amt of spp, and lowest rescue affect - 4Assumptions for estimating extinction rates1. estimates based on typical values for species- area curve
2. all endemic species are eliminated
3. habitats are eliminated at random
4. fragmentation may affect extinction rates - 5Rare Species (4)- live in narrow geographical range
- occupy only a few specialized habitats
- found only in small populations
- more likely to go extinct - 6Endemic vs. Neoendemic vs. Paleoendemic Speciesendemic = found naturally in single geographical area (high risk)
neodendemic = occupies small area bc they recently evolved from related species
paleoendemic = its close relatives have all gone extinct (last of their kind) (panda) - 75 Categories frequently used in conservation planning- species w/ narrow geographical range
- only a few populations
- small population sizes
- population size is declining
- species hunted or harvested by people - 8Categories of species linked to extinction (a lot)- need a large home range
- have large bodies
- not effective dispersers
- seasonal migrants
- little genetic variability
- have specialized niche requirements
- no prior human contact
- low reproductive rates - 9IUCN Conservation Categories (flowchart)
- 105 Criteria to be Red listed (critically endangered)A) low number of individuals
B) restricted range and predicted habitat loss
C) predicted decline in numbers
D) less than 50 mature individuals left
E) >50% chance to go extinct in 10 yrs/3 gen.
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- Fichas sobre Con Bio Lecture 5 - Extinction , creado por aharricharan el 22/04/2016.
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