BC= Billion years
Made from igneous, metamorphic, or other sedimentary rocks. When these rocks are exposed at the earth’s surface they begin the long slow but relentless process of becoming sedimentary rock. First sedimentary rock found in Greenland 3.8 billion years ago.
The first bacteria was cyanobacteriabacteria, cyanobacteria are larger than most bacteria, and may secrete a thick cell wall. More importantly, cyanobacteria may form large layered structures.
3.4 billions years ago.
Microbial mats are specialized microbial communities that are composed mainly of photosynthetic prokaryotes.
Carbon isotopes and fossil stromatolites are the evidence to early microbial life.
Large cells are present suggesting eukaryotic emdosymbiosis has occur and sexual reproduction is now present. 1.4 billion years ago.
First known multicellular organisms are formed. Are very jelly-fish like. 2.1 billion years ago.
Fossils from species like brachiopods, tribolites, anthropods are formed. 550 million years ago.
During this time period most continents came together to form super-continent Gondwana, also the first sea animals came to land; horse shoe crabs began to mate and spawn on land. 500 million years ago.
Corals and other marine organism thrived, also first land plants; didn’t have leaves at first but then turned into mosses and ferns. 440 million years ago.
Many fish and amphibians appeared during this time period; ray-fish and lobe-finned boney fish are examples. 400 million years ago.
Giant spore producing trees are abundant. 350 million years ago.
During carboniferous period, evolved from water animals; Hylonomous is the oldest know reptile. 345 million years ago.
Last period of the paleozoic era, largest mass extinction recorded in history of earth, Pangea was formed. 285 million years ago.
Started after mass extinction, beginning of Mesozoic Period and age of reptiles, dinosaurs evolved from archosaurs (lizard type things). 245 million years ago.
Pangea starts to drift apart, and many dinosaurs and first birds start to appear. 205 million years ago.
Jurassic period, developed from dinosaurs, Aves was the biological class these birds were in. 150 million years ago.
Warm climate and many shallow inland seas. New birds, mammals, and flowering plants appeared. Many dinosaurs stayed on land and reptiles were in the water. 140 million years ago.
Cretaceous-Tertiary (K/T) Extinction Event. This may have been caused by an iridium-rich meteorite or comet hitting Earth and causing dust to block out the sun. 65 million years ago.
Mammals/primates develop different characteristics. Ex: flat nails, thumbs, better vision. 60 million years ago.
Phosphatherium, small pig sized elephant. 5 million years after dinosaurs went extinct. 38 million years ago.
The animals crossed the ice bridge to Eurasia, and then dispersed to North America. 30 million years ago.
This was a time of global cooling after the warmer Miocene. The cooling and drying of the global environment may have contributed to the enormous spread of grasslands and savannas during this time. The change in vegetation undoubtedly was a major factor in the rise of long-legged grazers who came to live in these areas.
Studies show we are related to an ancestor that looked like a squirrel. The ankle bones show that it had a mobile ankle joint like primates today that live in trees. 2 million years ago.
Many genera and even species of Pleistocene conifers, mosses, flowering plants, insects,mollusks, birds, mammals, and others survive to this day. Yet the Pleistocene was also characterized by the presence of distinctive large land mammals and birds.
Around 130,000-110,000 years ago the Earth's climates were generally much like those of today, though somewhat warmer and moister in many regions. As the cold grew more severe, the Earth's climate also became drier because the global 'weather machine'.
10,000 years ago.