History of Life on Earth PDF

History of life on Earth Teacher: Zayra M.Atrero  Hadean Eon (4.6 to 4 billion years ago) Characteristics: This is the earliest eon in Earth's history, beginning with the formation of the Earth. It was a time of intense volcanic activity, frequent meteorite impacts, and a hostile environment w...

History of life on Earth Teacher: Zayra M.Atrero  Hadean Eon (4.6 to 4 billion years ago) Characteristics: This is the earliest eon in Earth's history, beginning with the formation of the Earth. It was a time of intense volcanic activity, frequent meteorite impacts, and a hostile environment with little to no life. Organisms: No life forms are thought to have existed during this period. Earth's surface was too hot for stable water bodies, and the atmosphere was likely made up of volcanic gases.  Archean Eon (4 billion to 2.5 billion years ago) Characteristics: During this time, the Earth's crust cooled, and the first solid continents formed. The atmosphere was still rich in methane and ammonia, and oceans began to form. Organisms: Prokaryotes (single-celled organisms without a nucleus), including bacteria and archaea, dominated the Earth. The earliest forms of life were likely anaerobic (not requiring oxygen). The first photosynthetic organisms, cyanobacteria, began to release oxygen, which would eventually lead to changes in Earth's atmosphere. Archean Eon (4 billion to 2.5 billion years ago) Archean Eon (4 billion to 2.5 billion years ago) Notable Events: The Great Oxygenation Event (around 2.4 billion years ago) occurred when cyanobacteria began producing oxygen, leading to a significant increase in atmospheric oxygen. Proterozoic Eon (2.5 billion to 541 million years ago) Characteristics: This eon saw the gradual increase in oxygen levels in the atmosphere and the development of more complex life forms. The first supercontinents began to form, and Earth experienced multiple ice ages. Organisms: The first eukaryotes (cells with a nucleus) appeared, followed by multicellular organisms. The earliest multicellular life forms were likely simple algae and other soft-bodied organisms. Proterozoic Eon (2.5 billion to 541 million years ago) Dickinsonia the first Red Algae animal on Earth Proterozoic Eon (2.5 billion to 541 million years ago) Notable Events: By the end of the Proterozoic, multicellular life became more diverse, and the first multicellular animals appeared. The snowball Earth hypothesis suggests that Earth may have experienced global glaciations during this time. Paleozoic Era (541 to 252 million years ago) 1. Cambrian Period (541 to 485 million years ago) 2. Ordovician Period (485 to 444 million years ago) 3. Silurian Period (444 to 419 million years ago) 4. Devonian Period (419 to 359 million years ago) 5. Carboniferous Period (359 to 299 million years ago) 6. Permian Period (299 to 252 million years ago)  Cambrian Period (541 to 485 million years ago): Characteristics: The Cambrian Explosion marked a rapid diversification of life forms, especially invertebrates. The first hard-shelled organisms, such as trilobites, appeared. Organisms: Diverse marine invertebrates, early arthropods, brachiopods, and mollusks dominated. The first vertebrates, like early fish, appeared. Trilobites  Ordovician Period (485 to 444 million years ago): Characteristics: Life was mostly marine, and the first jawless fish appeared. Organisms: In addition to early fish, corals, cephalopods, and primitive plants (such as mosses) began to colonize land. myllokunmingia  Ordovician Period (485 to 444 million years ago): Notable Events: A major mass extinction occurred at the end of the Ordovician, possibly due to climate change and glaciation.  Silurian Period (444 to 419 million ⚬ Characteristics: years ago): Stable climate, rise in biodiversity, and significant developments in plant life on land. cooksonia ⚬ Organisms: Sarcopterygii The first vascular plants appeared on land. Early tetrapods (four-limbed vertebrates) began to emerge from aquatic environments.  Devonian Period (419 to 359 million years ago): ⚬ Characteristics: Often referred to as the "Age of Fishes," the Devonian saw significant diversification of fish and the rise of the first forests on land. ⚬ Organisms: The first amphibians (early vertebrates that could live on land) evolved from fish. Ferns, horsetails, and club mosses Archaeopteris Forest dominated the terrestrial flora. ⚬ Notable Events: A major extinction event occurred at the end of the Devonian, affecting marine life. Ichthyostega  Carboniferous Period (359 to 299 million years ago): ⚬ Characteristics: This period saw the rise of vast coal swamps, which led to the formation of extensive coal deposits. It also marked the evolution of reptiles. ⚬ Organisms: Amphibians flourished, and reptiles appeared. Giant ferns and seed plants covered the land. ⚬ Notable Events: Gilboa Forest The first true forests and large-scale terrestrial life. Permian Period (299 to 252 million years ago): Characteristics: Therapsids The Permian ended with the largest mass extinction in Earth’s history, the Permian- Triassic extinction event, which wiped out nearly 90% of life on Earth. Organisms: Early dinosaurs and mammal-like reptiles (therapsids) appeared. nyasasaurus parringtoni Nyasasaurus Parringtoni  Permian Period (299 to 252 million years ago): Notable Events: The formation of the supercontinent Pangaea, leading to changes in climate and sea levels.  Mesozoic Era (252 to 66 million years ago) The Mesozoic Era is famous for the dinosaurs, the rise of birds, and the first appearance of flowering plants. 1.Triassic Period (252 to 201 million years ago) 2.Jurassic Period (201 to 145 million years ago) 3.Cretaceous Period (145 to 66 million years ago)  Triassic Period (252 to 201 million years ago) Trivia: The earliest dinosaurs were small, bipedal creatures that evolved during the late Triassic. Earth's Conditions: The climate was hot and dry, and the first dinosaurs began to dominate.  Triassic Period (252 to 201 million years ago) Key Event: The first true dinosaurs and the emergence of mammals. Life: The first dinosaurs like Coelophysis roamed the Earth. Example: Coelophysis, an early dinosaur, was relatively Coelophysis small but one of the first to appear.  Jurassic Period (201 to 145 million years ago) Trivia: The Jurassic period is known for the rise of the giant Brachiosaurus s a u r o p o d d i n o s a u r s l i ke Brachiosaurus and Apatosaurus.  Jurassic Period (201 to 145 million years ago) Earth's Conditions: The continents began to drift apart, creating new seas and coastlines. Jurassic Period (201 to 145 million years ago) Key Event: The first birds evolved from theropod dinosaurs (e.g., Archaeopteryx). Life: Dinosaurs dominated both land and sea, while early mammals were still small and nocturnal. Archaeopteryx Example: Archaeopteryx, considered one of the first birds, is a key example of early dinosaur-bird evolution.  Cretaceous Period (145 to 66 million years ago) Trivia: The Cretaceous ended with the K-T extinction event, wiping out the non-avian dinosaurs. Earth's Conditions: Flowering plants evolved and spread, and the first mammals began to diversify.  Cretaceous Period (145 to 66 million years ago) Key Event: The Cretaceous-Paleogene extinction event, likely caused by an asteroid impact, led to the extinction of the dinosaurs. Life: Dinosaurs were still dominant, but mammals began evolving larger sizes. Example: Tyrannosaurus rex, one of the largest predatory dinosaurs, lived during the late Cretaceous. Cenozoic Era (66 million years ago to present) The Cenozoic Era is characterized by the rise of mammals, the appearance of humans, and the development of modern ecosystems. 1. Paleogene Period (66 to 23 million years ago) 2. Neogene Period (23 million years ago to 2.6 million years ago) 3. Quaternary Period (2.6 million years ago to present)  Paleogene Period (66 to 23 million years ago) Trivia: The Paleogene period saw the rise of mammals into large, diverse forms. Earth's Conditions: The Earth's climate cooled, and the first primates (Plesiadapiforms) appeared. Purgatorius  Paleogene Period (66 to 23 million years ago) Key Event: Mammals rapidly evolved into many forms, filling ecological niches left vacant by the extinction of dinosaurs. Life: Early primates, whales, and bats appeared. Example: Protocetids, early whale ancestors, lived in shallow waters. Protocetids  Neogene Period (23 million years ago to 2.6 million years ago) Trivia: The Neogene period includes the evolution of early humans. Earth's Conditions: Modern ecosystems began to develop, and Earth's climate cooled further. Key Event: The evolution of early hominids and the spread of grasslands.  Neogene Period (23 million years ago to 2.6 million years ago) Life: Early humans appeared, alongside large mammals like mammoths and saber-toothed cats. Example: Australopithecus, one of the earliest human ancestors, lived in Africa during this time.  Quaternary Period (2.6 million years ago to present) Trivia: The Ice Ages were a defining feature of the Quaternary, with the rise of Homo sapiens (modern humans). Earth's Conditions: Ice sheets covered large portions of Earth, and modern climates and ecosystems emerged.  Quaternary Period (2.6 million years ago to present) Key Event: The extinction of many large mammals (e.g., woolly mammoths) and the rise of modern humans. Life: Humans became the dominant species on Earth, using tools and developing complex societies. Example: The woolly mammoth was an iconic species during the Ice Age before its extinction around 4,000 years ago. Thank You