University:
University of Cincinnati
Course:
BIOL 2084C | Evolution and Ecology
Academic year:

2023
Views:

151

Pages:

3
Author:

awing997pgyd

Evolution of Multicellular Life Precambrian Time • • • Earth Forms First Life (Bacteria) First multicellular organisms Life existed only in the sea. The Start of the Paleozoic Era Cambrian Explosion Appearance of many complex lifeforms Paleozoic Era 540 MYA - 250 MYA Rich fossil evidence shows that early in the Paleozoic Era, there was a diversity of marine life. The Paleozoic Era 450 A - 360 MYA - The first vertebrates appeared. The first land plants - Insects appear on land Most fishes had jaws, bony skeletons, and scales Vertebrates began to invade the land. The Paleozoic Era 360 MYA - 250 MYA - Reptiles evolved from certain amphibians. Winged insects Vast swampy forests. Remains of ancient plants formed thick deposits of sediment that changed into coal over millions of years. The end of the Paleozoic Worst Mass Extinction ever 95% of the complex life disappeared. Mesozoic Era 250 MYA - 65 MYA - The age of the dinosaurs First flowering plants Triassic Period 245-208 MYA Organisms that survived the Permian mass extinction became the main life forms early in the Triassic. These organisms included fishes, insects, reptiles, and cone-bearing plants. Jurassic Period 208-145 MYA Dinosaurs became the dominant animals on land. One of the first birds, Archaeopteryx, appeared. Cretaceous Period 145-65 MYA Dominant animals during this period included: reptiles, birds, turtles, crocodiles, fishes, and marine invertebrates, leafy trees, shrubs, and small flowering plants. The end of the Mesozoic Era The Cretaceous Period ended with a mass extinction. More than half of all plant and animal groups were wiped out, including all of the dinosaurs. Cenozoic Era 65 MYA - Present -The age of mammals During the Cenozoic, mammals evolved adaptations that allowed them to live in various environments—on land, in water, and even in the air. The Cenozoic often is called the Age of Mammals. The Cenozoic is divided into the Tertiary Period and the Quaternary Period. Tertiary Period 65 MYA - 1.8 MYA - Marine mammals evolve (whales, dolphins) Some mammals became very large, as did some birds. How big were mammals before the mass extinction that ended the Mesozoic Era? Quaternary Period 1.8 MYA - Present - Series of ice ages until 20,000 YA. In the oceans, algae, coral, mollusks, fishes, and mammals thrived. Insects, birds, and land mammals were common. Early Humans Early ancestors first appeared 4.5 million years ago. The first fossils of Homo sapiens 200,000 years ago in Africa.