EE Lecture 40: Biodiversity through Time Flashcards
what was the traditional view of biodiversity through time
short period where diversity arrived, then a coinstant level
how many mass extinctions have there been
five
what were the mass extinctions
End Ordovician Late Devonian End Perminan End Triassic End Cretaceous
what evidence is there to show that we are in the 6th mass extinction
50% of all secies disappearing
why isnt todays current extinction not enough to be considered a mass extinction
its only 50% wherease past extinctions were over 75%
how many orders of magnitude greater than background extinction rates, are our current extinction rates
1 or 2
compare current extinction rates to background extinction rates
current extinction rates are 1 or 2 orders of magnitude above background extinction rates
what drives diversity dynamics (2 hypotheses)
- Court Jester
2. Red Queen Hypothesis
what is the red queen hypothesis
competition suppresses speciation or increases extinction - logistic pattern of diversification
its BIOTIC : diversity
what is the Sepkoski curve
it corrects/accounts for temporal and sampling bias of fossils by using families
what is the Court Jester hypothesis
environmental pertubations (damage) reset diversity = exponential pattern and mass extinction ABIOTIC
what pattern do fossil records suggest?
logistic pattern - by trying to correct for bias
what is the likelihood of representation in the fossil record of a species correlated with
its abundance and geographic range
what increases the chance a species will be known in fossil record
high abundance and wide geographic distribution
when will rate of change of alleles be highest
when allele is at intermediate frequencies
