ECOL 1000 1nd Edition Lecture 21 Outline of Last Lecture I. Tropical BiodiversityII. Why care about diversity?a. Nature’s medicine cabinetIII. Components of DiversityOutline of Current Lecture II. MacArthur-Wilson Equilibrium Model III. Passenger pigeonIV. Carolina parakeetV. Extinction EventCurrent Lecture- MacArthur-Wilson Equilibrium Model for Island Biogeography: model compares immigration extinction rates as a function of patch size and patch isolationo As more species are added the rate of colonization decreaseso Looks at extinction rates and island size Rate of extinction is lower on larger islands-larger islands can hold more species- Equilibrium shifts to the right, greater numbero Extinction rates and distance from mainland Islands near the mainland have more species than islands far away Near islands have a higher rate of colonization and shift equilibrium to the right- Mamala tree: extracts formed new drug “prostatin”o Didn’t help fight cancero Used to fight hiv- Biodiversity- Extinction is normal- Passenger pigeonThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Initially huge flockso Communal bird, with hundreds of nests togethero Hunted by native americans and colonistso 1850s railroads gave easier access to hunting and easier to transport bird meato The last one “Martha” died in captivity in 1914o Allee effect-did not reproduce when population got low- Carolina Parakeeto Lived in eastern USo Habitat destruction, hunting for feathers, collecting for pets, being shot as “pests” greatly reduced populationo Went extinct-perhaps because of contact with poultry disease Kept in close contact with domestic animals and contracted a disease from chickenso The last one “Incas” died in captivity in 1918- Extinction event: a sharp decrease in the diversity and abundance of macroscopic life, and occurswhen the rate of extinction increases with respect to the rate of speciationo In the past 540 million years there have been 5 major extinction eventso The most recent , the Cretaceous extinction event - The background rate of extinction is the average rate of extinction that occurred before the appearance of humanso Based on fossil recordo About 1 species out of every 1 million per
View Full Document
Unlocking...