evolution lecture 2 Flashcards
natural selection in action example
- drug resistance in pathogenic microrganisms
- pesticide resistance
- host-switching in insects
example 1 of natural selection: warfarin resistance in rats
- warferin interfers with blood-clotting agents which means you might not stop bleeding when cut –> death
- mutations in gene associatied with warfarin resistence
- resistance increases rapidly in populations after poisoning is introduced
example 2 of natural selection: soapberry bugs
- fruit bugs feed on is fat
- flatter kin of fruit becomes widley spread
- shorter beaks in soapberry bugs are favoured
- shorter beaked soapberry bugs increase in population
evidence for tree of life/ descent with modification?
- homology
- biogeography
- fossil record
homology
- similarity resulting from common ancestory
what is “standard” anatomical homology?
structures with different function, same form
- wing of bat, fin of whale, leg of cat, arm of human
vestical structures
structures with little or no function, coming from more comicated structures
- hind- limb bone in whales
embryological homologies
- organs that share common form during development but different dtructures and/or functions once developed
molecular homologies
homologies on biochemical level
- universal genetic code
analogous structures
similar functions, not similar structure
- ‘convergent evolution’
biogeography
the geographic distributions of organisms
- some taxa are restricted to certain locations
- explanation? : descent from common ancestor that lived in that location
what does endemic mean?
animal restricted to certain region
the fossil record
descent with modification predicts TRANSITIONAL FORMS
what are transitional forms?
the fossilized remains of a life form that connected n ancesteral group to a current living descendant group
