BIO120H1 Lecture Notes - Lecture 3: Archimedes Palimpsest, Kiwi, Goose Bumps

• School: UTSG
• Department: Biology
• Course: BIO120H1
• Professor: Spencer C H Barrett

Document Summary

Palimpsests (cid:396)e(cid:272)(cid:455)(cid:272)led (cid:373)a(cid:374)us(cid:272)(cid:396)ipts used (cid:271)(cid:455) (cid:373)edie(cid:448)al (cid:449)(cid:396)ite(cid:396)s; (cid:373)ea(cid:374)s (cid:862)s(cid:272)(cid:396)aped agai(cid:374)(cid:863) Similar to ancient text, organisms are palimpsests of evolutionary history: within the bodies of animals/plants there are clues to their ancestry, molecular palimpsests their genomes is inscribed much of their evolutionary history. Why did some species lose their ability to fly: most birds that evolved flightlessness did so on islands, lack of mammals and replies (species that prey on birds) on these islands. If predators are often missing on islands or if food is readily obtained on the ground, fully functioning wings are not necessary since it takes up a lot of energy that could be diverted to reproduction. Birds with reduced wings have a reproductive advantage, wings can easily be injured therefore natural selection could favour flightlessness. Size/degree of development vary the length varies from 1 inch to over 1 foot in humans, some people are born without one.