Ch 6 - Geography of Evolution Flashcards
Realms
Some related ones divided by continental drift; after that very little exchange between them
Smaller realms
provinces of flora and fauna shaped by long term weather patterns
Cape York Peninsula in Australia
Mega diverse area in NE Oz
Hardy-Weinburg math and criteria
For Diploid, (p + q)(p + q) = 1; no mutation, no gene flow, no inbreeding, no selection, very large population
Wright
We move away from Hardy-Weinburg; assume inbreeding occurs; Hsj = probability alleles are different; F statistics,
Disjunct distributions
Closely related species found on different continents, evidence of common ancestor that was then separated by continents (ex. cichlids, gators, some pines)
Human influences
European starling: 100 released in New York in 1896. Expands to cover most of NA by 1970.
Saxifrage example. Why at certain disconnected high elevations?
Would have been pushed South by glaciers. Would have died out at lower altitudes as glaciers receded, so they remained at high elevations and in Arctic
How do lineages diverge?
Food source changes (common in insects); geographic dispersal or migration, vicariance (a barrier like a mountain range or climate); behavioural;
Breakup of Gondwanaland*
Break off of antartica; first India and Madagascar which then split; South America last 35 Mya
Hawaiian cricket species
Spread from one island to another as they emerged; don’t go backwards, no extinctions
Lemurs
Phylogenetic analysis shows that they stemmed from African monkeys and then colonized Madagascar after it had already split off. Neat.
Allochthonous
Taxa that originated elsewhere, arrive by dispersal (eg Hawaii)
Autochthonous
Evolved within an area (flightless birds of SA, Africa, NZ, Oz; Lungfish of SA and Africa)
Basal group (fig 6.13)
A branch that diverges earlier, usually show place of origin