ANT203Y1 Lecture Notes - Lecture 13: Adapis, Treeshrew, Mesozoic
Document Summary
Last period of the mesozoic (paleocene) is when mammals first appeared: cenozoic the age of mammals . Primates, tree shrews, flying lemurs and bats are more closely related to each other than other. Stem group: all taxa in a clade before a major speciation event: don"t have the derived shared characteristics. Crown group: all of the taxa that come after major speciation event: do have the derived shared characteristic. Sister group: two new clades that result from the splitting of a single common lineage. 225 mya all continents were one, called pangaea. 135 mya there were two main continents, laurasia (north) and gondwanaland (south: dinosaurs were extinct by this point. 65 mya continents looked more like they do today, with some differences here and there. Important to study continental drift because of: where the continents are can effect climate and therefore the species of that area, different environments (and species within) have to adapt to these gradual changes.
