Evolution of Australian Biota

220-110 (dinosaurs)
1. Aust. still joined to Antarct. cool wet climate semi darkness for weeks in winter, shallow sea
2. Fossils of club mosses, narrabeen shales
45 mya
1. Aust. became separate
2. Fossils of aquatic organisms (crocodiles found in dry inland
20 mya
1. Aust. isolated from other continents and drifting northward. Climate was warmer and wet.
2. Tree rings are circular patterns made up of light and dark bands of woody tissues. There are more bands in summer, rapid growth but no bands in winder. Fossilised trees show this pattern of growth.
8 mya Continued northward drift, becoming drier.
100 thousand years (megafauna)
1. Drifted very close to present day position and decrease sea levels made it temporarily connected to tasmania and NG by land bridges.
10 thousand years
1. Cycles of high and low seas due to freezing and melting of the ice caps, land bridges forming
5 thousand years
1. Present plants show adaptations to harsh dry conditions have leathery leaves. Open forests, heathlands. No fossil remains have yet been discovered

Resource summary

	Created by kara.duncan183 over 10 years ago