ERTH 2401 Lecture Notes - Lecture 21: Permafrost, Northern Hemisphere, Mesozoic

• School: Carleton University
• Department: Earth Sciences
• Course: ERTH 2401
• Professor: Claudia Schröder-Adams

Document Summary

Ma(cid:373)(cid:373)als: evolution, lati(cid:374) (cid:449)ord (cid:858)u(cid:374)roll(cid:859, changes through time, proposed by charles darwin (cid:862)o(cid:374) the origi(cid:374) of pe(cid:272)ies(cid:863, principal of natural selection. Individuals compete for space, food and other resources. Fossil record where we are certain it is a mammal is not large: something hard that we have a good fossil record for is teeth. Records exist for certain lineages starting in triassic, into jurassic, cretaceous, and then tertiary: evolution of mammals, origin in late triassic, earliest finds date 225-220 ma, these barely made it over the triassic extinction, were very small: ex. Jurassic to cretaceous: 5 orders of primitive mammals had evolved (small still but a radiation, multituberculates, symmetrodonts, pantotheres, marsupials, placentals. Locomotion from sprawling to semi-erect: change of elbows and knees, ha(cid:374)ds a(cid:374)d feet (cid:373)o(cid:448)ed (cid:272)loser to (cid:271)od(cid:455)(cid:859)s (cid:272)e(cid:374)ter of gra(cid:448)it(cid:455, a reptile adopts a sprawling gait with the limbs emerging horizontally from the.