Evolutionary History of Life on Earth PDF

TOPIC 2 EVOLUTIONARY HISTORY OF LIFE ON EARTH Prepared by: Sheryl H. Dungog  Learning Objectives: Identify the dates and sequence of the periods in the geologic time scale; Identify the major events in each major period;...

TOPIC 2 EVOLUTIONARY HISTORY OF LIFE ON EARTH Prepared by: Sheryl H. Dungog  Learning Objectives: Identify the dates and sequence of the periods in the geologic time scale; Identify the major events in each major period; Identify the different types of fossils; Explain the causes of mass extinctions; and Suggest ways on how to protect the endangered species from deterioration and extinction. GEOLOGIC TIME SCALE Geologic Time Scale is a record of life forms and geologic events in Earth’s history. Key Concept: Because the time span of Earth’s past is so great, geologists use the geologic time scale to show Earth’s history. GEOLOGIC TIME SCALE In the geologic time scale, time is divided into bigger blocks than years or centuries. The scale begins when Earth formed 4.6 billion years ago and goes to the present.  DIVISIONS OF GEOLOGIC TIME SCALE eo The largest unit of time is an eon. An eon is an extremely long, indefinite period of time. n Division in an Era that span time periods of tens to hundreds of millions of years era period A division of geologic history that spans no more than one hundred million years The smallest division of the geologic time scale characterized by distinctive organisms epoc Eons: Precambrian: Earliest span of time Phanerozoic: Everything since Eras: Paleozoic Mesozoic Periods: Cenozoic Cambrian Ordovician Paleozoic Silurian “Age of Devonian Invertebrates” Carboniferous (Missipp. & Pennsylvanian) Permian Epochs: Triassic Paleocene Jurassic Eocene Mesozoic Cretaceous Oligocene “Age of Reptiles” Paleogene Neogene Miocene Quaternary Cenozoic Pliocene “Age of Mammals” Pleistocene Holocene PRECAMBRIAN TIME (4.6 Billion Years Ago) This period is MOST of Earth’s history. For nearly 4 billion years, during most of Precambrian time, no plants or animals existed. Multicellular organisms develop late in the Precambrian.  PALEOZOIC ERA (544 Million Years Ago) LIFE EXPLODES! At the beginning of the Paleozoic era, all life lived in the oceans. Early invertebrates developed and later reptiles became dominant on land. Early plant included simple mosses, ferns, and cone-bearing plants.  PALEOZOIC ERA Divided into 6 periods: 1. Cambrian period Sponges, snails, clams, and worms evolve 2. Ordovician period First fishes evolved and other species become extinct  CAMBRIAN EXPLOSION Cambrian explosion is the belief that there was a sudden, apparent explosion of diversity in life forms about 545 million years ago. The explosion created the complexity of multi-celled organisms in a relatively short time frame of 5 to 10 million years. This explosion also created most of the major “extant” animal groups today. PALEOZOIC ERA 3. Silurian period Land plants, insects, and spiders appear 4. Devonian period Amphibians evolved and cone-bearing plants start to appear.  PALEOZOIC ERA 5. Carboniferous period Tropical forests appear and reptiles evolve 6. Permian period Seed plants become common and insects and reptiles become widespread. Sea animals and some amphibians begin to disappear. MESOZOIC ERA (245 to 65 Million Years Ago) Age of the Reptile/Dinosaurs Dinosaurs lived along with the first mammals, birds, and flowering plants. Reptiles were dominant. The era ended with the great meteorite impact and caused mass extinction wiping out all dinosaurs.  MESOZOIC ERA Divided into 3 periods: 1. Triassic period Turtles and crocodiles evolve and dinosaurs appear. 2. Jurassic period Large dinosaurs roam the world. First mammals and birds appear. MESOZOIC ERA 3. Cretaceous period Flowering plants appear, mammals become more common, dinosaurs become extinct.  CENOZOIC ERA (65 mya to Present Day) The first humans appeared in the later part of the Cenozoic era, which continues today. The diversity of life forms increased. New mammals and birds appeared while other became extinct. Flowering plants became most common. CENOZOIC ERA (65 mya to Present Day The Cenozoic Era is only a tiny fraction of Earth’s geologic history.  CENOZOIC ERA Divided into 2 periods: 1. Tertiary period First primates appear and flowering plants become the most common. 2. Quaternary period Humans evolve and large mammals like woolly mammoths become extinct. We live in the Cenozoic era! Present day Earth is in the Cenozoic era and the Quaternary period in the Holocene epoch. Geologic time has NOT ended! MYA ERA PERIOD EPOCH LIFE -Mastadons become extinct 0.01 Holocene -Human culture flourishes -Accelerating extinction of many species Quaternary -Modern humans develop 1.8 Pleistocene -Asians arrive and settle the Americas 5.3 Pliocene Hominids develop Cenozoic Horses, mastadons, mammoths, tigers, and camels 23.8 “Age of Mammals” Miocene live in South Carolina 33.7 Oligocene Cats, dogs, and apes appear Tertiary -Grass spreads widely 54.8 Eocene -Diverse array of animals develop, including whales, rhinos, and elephants -First horses appear (size of a cat) 65.0 Paleocene -Tropical plants dominate -T-Rex develops but number of dinosaur species decline 144 Cretaceous -Snakes appear and first primates appear -Angiosperms appear Mesozoic “Age of Reptiles” -First birds appear 206 Jurassic -Golden age of dinosaurs First dinosaurs, mammals, crinoids, and modern 248 Triassic echinoids appear -90% of Earth’s species become extinct, including 290 Permian trilobites, blastoids, fish and amphibians because of heavy volcanism in Siberia  -Reptiles develop from amphibians 320 Pennsylvanian Carbo -Flying insects appear nifero us -First seed plants appear 354 Mississippian -Sea life flourishes including coral, brachiopods, blastoids, and bryozoa -Dominant animals: fish 417 Devonian -Amphibians, evergreens and ferns appear First land plants appear and land animals 443 Silurian follow -First animals with bones appear 490 Ordovician -Dominant animals: marine invertebrates including corals and trilobites -Explosion of life -All existing phyla came into being here -Life forms in warm seas as oxygen levels rose 540 Cambrian enough to support life -Dominant animals: trilobites and brachiopods No life possible as the Earth initially forms 4.6 billion years ago. Simple, single-celled forms of life appear 3.8 Precambrian billion years ago. They will become more 4600 (Hadean, Archean, and Proterozoic Ages) complex and successful over the next 3 billion years: Prokaryotes then Eukaryotes Cyanobacteria begins producing free oxygen (photosynthesis) FOSSILS A fossil is the preserved remains of an organism that has died. Fossils tell scientists, called paleontologists, about living things such as their biology and environmental conditions over earth’s history through the rock record. In addition, they give clues to the conditions of the earth (i.e. climate) at the time that the fossil was preserved and possibly relate changes of an organism over time. TYPES OF FOSSILS  ESSENTIAL QUESTIONS 1. How will you describe what was the Earth like millions of years ago? 2. How can fossils be used as evidence for the evolution of living forms? 3. How does understanding of geologic time and the significant geologic events of the past impact your understanding of humans’ unique responsibility and place on Earth? 4. How does understanding the past help us understand the present?  Learning Task 2 – long-sized bond paper Personal Timeline: Create a timeline of events that happened to you since you were born up to the present time. Choose only 20 events that you think are the most important. Time Machine: Look around your community. Make a narrative on how the place looked like several years ago and how it will be several years (maybe after 50 years) from now. Deadline: a week from now