4.6 bya earth starts
3.7-3.8 bya carbon isotopes found in greenland- biomarkers
2.2 bya eukaryotes arise
600-800 mya first metazoans appear
700-800 mya oldest animals- may have been older but didn't leave fossils
650 mya earth was frozen and possible cause of cambrian explosion.
from 570 mya (precambrian) until cambrian era. they are fossils of exixsting phyla cnidarians. enigmatic tubular and frond-shaped, mostly sessile organisms
543 mya trace fossils show at start of cambrian and indicators of activity. Tracks and burrows.
small shelly organism arise
trilobites 520 mya easily fossilized and extremely successful and diverse early animal. died in the devonian and permian extinction
450 mya first big mass extinction- global cooling- first forests too up all the CO2 and caused global cooling
after first vascular plants on land we have first invertebrates on land in silurian
silurian is first common vascular plants.
fish develop jaw
400 mya devonian. first forests
first vertebrates go to land in the devonian - co evolution with first forests.
375 mya extinction pulses green house gasses was a prolonged time
251 mya largest extinction the great dying. rapid warming. possible methane explosion.
250 mya therapsids take over. mammal ancestors. were replaced by diapsids.
220 -65 mya archasaur is first bipedal animal and gave rise to dinos
205 mya global warming
145 mya first known bird
first angiosperm that cause a severe radiation in animals and plants. soon 90% of plants were flowering
impact extinction dinos go extinct.
Australopithecus developed bipedalism as they left forests for grassland
4-2.75 mya1.2 m tall, bipedal, strong sexual dimorphism, ape-like features, massive brow ridges, low forehead, forward jutting jaw
Brain capacity - 380-450 cc
10-20% larger than modern chimps -
30-35% of modern hominids
3-1.6 mya Minor differences from afarensis
1.4 m tall, slightly flatter face
Brain capacity - 400-600 cc
homo genus arrives
Similar thigh and pelvis bones
First use of stone tools
Chopper/ Pebble tools
2 mya brains significantly enlarged in hominoids
More complex stone tools
Homo sapiens sapiens and
homo sapiens neaderthalenis
lower forehead; prominent, heavy brow ridges; weak chin.
Body tends to be more massive and more heavily muscled with shorter limbs.
Lived in caves in Europe
Made highly specialized tools of stone and bone
Buried their dead in ritual burials
first eon 4.6-4 bya
3.8 bya to 2.5 bya
eon - 2.4 bya - 544 mya
544 mya to present eon
544 to 248 mya era
era 248-65 mya
65 my to present era
beginning of earth to cambrian
4.6 bya to 544 mya
440 - 410 mya
410 to 360 mya
360 to 286 mya
268 - 248 mya
248 to 213 mya period
213 mya to 145 mya period
145 mya to 65 mya
65 mya to 1.8 mya period
1.8 mya to present