Precambrian - hadean eon ( origin of earth)
4600
4000 Precambrian
archaean eon( origin of protocells)
3500 ma precambrian
arcanean eon - oldest fossils of cells appear these cells are called prokaryotic meaning their genetic material dna is not contained in the nucleus
2700ma precambrian - archaean eon
concentration of atmospheric oxygen begins to increase ( oxygen evolution)
2000ma precambrian ( Proterozoic eon )
oldest fossils of eukaryotic cells appear;. Eukaryotic cells have a nucleus to contain their genetic information
1500 ma precambrian - proterozoic eon
earliest multicellular eukaryote fossils appear. more complex forms of life are now emerging.
635
the ediacaran biota appears in the fossil record. these are diverse algae and soft bodied
541ma paleozoic
the Cambrian explosion is an event that is characterized by a rapid diversification of many animal phyla ( groups). increased competition and predator- prey relationships leads to an evolutionary arms race causing the sudden appearance of defensive and predatory body parts like armour and claws
485 ma paleozoic - ordovician period
colonization of the land by living organisms. The first land Fungi, animals( insects) and land plants. The first land plants were the bryophytes ( mosses). These plants are small because they are non vascular plants. meaning they do not possess vascular tissues to transport water and nutrients.
444ma - paleozoic - silurian period
appearance of the first seedless vascular plants. These plants possess vascular tissues to transport water and nutrients through their bodies so they could grow larger than the already existing bryophytes.
419ma - paleozoic - Devonian period
diversification of bony fishes and first appearance of tetrapods , four legged land animals that evolved from lobed finned bony fishes
393 ma - paleozoic period - middle Devonian period
appearance of the gymnosperms, the first seed bearing vascular plants. Well- developed vascular tissues and the protected seeds allowed these plants to proliferate into the dominant form of plant on earth
359 - paleozoic 0 carboniferous period
extensive forests of vascular plants ( gymnosperms)
amphibians are the dominant land animals and are closely tied to water for reproduction. The first amniotes, the reptiles evolve. These animals have soft shelled amniotic eggs which make them able to reproduce on land without their eggs desiccating.
299 ma - paleozoic - permian period
radiation of reptiles and most present day groups of insects
252ma - paleozoic / mesozoic - permian - triassic period boundary
end permian extinction - the largest extinction event in earths history marked by the eradication of 96% of marine organisms and most terrestrial organisms due to global warming and oxygen depletion
252 ma - mesozoic - triassic period
extinction of most organisms on earth at the end of the permian opened niches for new organisms to proliferate. Gymnosperms dominate the landscape and a group of reptiles, the archosaurs evolve and become the dominant land animals. Archosauria includes crocodilians, pterosaurs and avian and non avian dinosaurs
201 - mesozoic - jurassic period
gymnosperms continue to be the dominant plants on land. Dinosaurs are large abundant and diverse
145 - mesozoic - cretaceous period
angiosperms, the flowering plants appear and rapidly become the dominant form of land plants
66 ma - mesozoic/ cenizoic - cerataceous paleogene
the end cretaceous mass extinction event caused by long standing volcanism from the Deccan traps in what it is now western India
66 ma - cenozoic - paleogene period - paleocene epoch
the abundant open niches in earths ecosystems allowed for the major radiation of mammals and of the last dinosaurian lineage, the birds. Eventually, the mammals become the dominant large terrestrial animals on earth.
56 ma - paleogene period- Eocene Epoch
angiosperms continue to dominate the land. Most present day mammalian orders are established including early primates
34 ma - cenozoic - paleogene period - oligocene epoch
continued radiation of mammals, including many ungulate ( hoofed mammal) groups
23 ma - cenozoic - neogene period - miocene epoch
mammals and angiosperms continue to dominate the land. The first apes, including ape like ancestors of humans evolve.
5 ma - cenozoic - neogene period - Pleistocene epoch
the most recent glaciation events the ice ages occur. the Pleistocene megafauna, extremely large mammals, dominate the landscape but will mostly become extinct by the end of this epoch. First appearance of Homo sapiens
