Geological Time Chart
(Evolution of major groups of animals)
| Era | Period | Epoch | Million Years | Organisms evolved |
Coenozoic | Quaternary | Holocene | 0.01-0 | Dominance of man. Domestication of animals and agriculture. Modern genera and species evolved. Last ice age 30-40 thousand years ago. Woolly mammoth extinct. |
Pleistocene | 1.5-0.1 | Mass extinction. Huge floods. Ice age. Many large mammals extinct. Mastodons and woolly mammoth extinct. Prehistoric man evolved. Cave paintings. | ||
Tertiary | Pliocene | 6-1.5 | Dry climate. Oceans shrink. Mammals increase specialization. Mountains rise. First hominids appear. First orchids. | |
Miocene | 23-6 | Ice age. First man-like apes. Evolution of apes, monkeys, horse, elephant. Radiation of grazing mammals. Huge grasslands. All grass subfamilies distinct. | ||
Oligocene | 37-23 | Archaic mammals attain their maximum diversity. Creodonts (archaic carnivores) appear. First apes. Origin of grasslands. | ||
Eocene | 53-37 | Forests of monocotyledons and flowering plants appear. Ancestors of horse, camel, elephant appear. First bats. | ||
Paleocene | 65-53 | Climate warm. Vegetation abounds. Ancestors of most modern mammals appear. Insectivores abundant. First grasses, Rhododendrons, whales and rodents. | ||
Mesozoic | Cretaceous | 135-65 | Mass extinction. 60% of tetrapod families extinct. Himalayas, Andes, Alps arise. Dinosaurs and Ammonites extinct. First monocotyledons. First marsupials and placental mammals (Pantotheres). First flowering plants. Climate cool. Angiosperms radiate. | |
Jurassic | 205-135 | First bird, Archaeopteryx. Dominance of dinosaurs. Earliest mammals. Dicotyledons and conifers common. Continents become high. Origin of insect pollinators. | ||
Triassic | 250-205 | Massextinction. 80% of tetrapod families extinct. Continental drift begins. Arid conditions. Gymnosperms dominate. First dinosaurs.Mammal-like reptiles. First teleosts, first crocodiles and first flying reptiles. | ||
Palaeozoic | Permian | 290-250 | Mass extinction. 70% of tetrapod families extinct. Single land mass, Pangaea and single ocean. Continents rise. Glaciations set in. Expansion of reptiles, origin of Cotylosauria and Therapsida. Last trilobites. | |
Carbonife- rous | Pennsylva- nian | 290 | Warm and humid climate. Swamps abundant. First modern soils. First reptiles. Sharks abundant. First mammal-like reptiles. Earthworms. | |
Mississipp- ian | 350 | Forests of ferns and gymnosperms. Foraminiferans and shell-crushing sharks abound. First winged insects. Radiation of amphibians. Little seasonal variations. | ||
Devonian | 410-350 | Mass extinction. Arid climate. First gymnosperm forests. First amphibians (Labyrinthodonts). First spiders. Dominance of fishes. First ferns. First vascular plants. First insects. | ||
Silurian | 440-410 | Algae dominate. Land plants definite. Trilobites decline. First scorpions and millipedes appear. First fishes, ostracoderms and placoderms appear. | ||
Ordovician | 510-438 | Land submerged. Warm climate. Algae abound. Plants invade land. First corals. First vertebrates. Cephalopods and snails. First Agnatha. | ||
Cambrian | 600-510 | Mass extinction. Mild climate. Marine algae. Many invertebrates. Trilobites. Brachiopods. Sponges. Molluscs. Explosion after mass extinction. | ||
Proterozoic | 3,500-600 | Primitive aquatic algae and fungi. Annelid burrows. Protozoa. Oxygenation of atmosphere. Prokaryote radiation. Skeleton of sponges. | ||
Archeozoic | 4,600-3,500 | Calcareous deposits by algae. Origin of life. Fossils of cyanobacteria. | ||
Solar | 5,000-4,600 | Formation of Solar system. Strong solar wind. Formation of primitive atmosphere on earth. | ||
Cosmic | 20,000-5,000 | Big Bang and matter synthesis. |