History of Life

Cards (25)

  • Fossils
    • remnants, impression, or trace of an animal or plant of a past geologic age that has been preserved in Earth’s crust.
    • Fossil Record - primary source of information about the history of life on Earth.
  • Geologic Time Scale
    • a record of life forms and geologic events in Earth’s history. Divided into Eon, Era, Period, and Epoch.
  • Eon
    • the largest division of geologic time scale; half billion - nearly 2 billion years.
    • 88% happened during the PRECAMBRIAN represented by HADEAN, ARCHEAN, AND PROTEROZOIC EONS.
  • Eons
    1. Hadean
    2. Archean
    3. Proterozoic
    4. Phanerozoic - current geological eon that began approximately 541.0 million years ago.
  • Era
    • Division that spans time periods of tens to hundreds of millions of years.
    • Phanerozoic eon eras:
    • Paleozoic
    • Mesozoic
    • Cenozoic
  • Periods
    • division in geologic history with spans of no more than 100 million years.
  • The Paleozoic Era
    meaning ”ancient or old life”. It started more than 540 million years ago. Many organisms that have emerged during this time were invertebrates.
  • Periods of Paleozoic Era:
    1. Cambrian
    2. Ordovician
    3. Silurian
    4. Devonian
    5. Carboniferous
    6. Permian
  • Cambrian Period
    • following the Precambrian mass extinction, there was an explosion of new kinds of organisms.
    • sponges evolved and small ocean invertebrates called trilobites were very abundant.
  • Ordovician Period
    • oceans were filled with invertebrates of many types.
    • The first fish evolved. Plants colonized the land for the first time, but animals still remained in the water.
  • Silurian Period
    • in the oceans, corals appeared and fish continued to evolve.
    • Vascular plants appeared. With special tissues to circulate water and other materials.
  • Devonian Period
    • The first seed plants evolved. Seeds have a protective coat and stored food to help them survive.
    • Fish with lobes, and fins evolved. They could breathe air when they raised their heads above water
  • Carboniferous Period
    • widespread forest of huge plants left massive deposits of carbon that turned into coal.
    • The first amphibians evolved to colonized land, but they need to return to water to reproduce.
    • the first reptiles evolved. They were the first animals that could reproduce on dry land.
  • Permian Period
    • major land collided to form a supercontinent called Pangaea.
    • Temperature was extreme, and the climate was dry.
  • Mesozoic Era
    • Also known as the “Age of Reptiles” that started more than 280 million years ago.
  • Periods of Mesozoic Era
    1. Triassic Period
    2. Jurassic Period
    3. Cretaceous Period
  • Triassic Period
    • The first dinosaurs branched off from the reptiles and colonized the land, air, and water.
    • Huge seed ferns and conifers dominated the forest.
    • The supercontinent Pangea also started to separate into Laurasia and Gondwanaland.
  • Jurassic Period
    • “The Golden Age of Dinosaurs”, earliest birds evolved from reptile ancestors.
    • Flowering plants also appeared for the first time and new insects also evolved to pollinate the flowers.
  • Cretaceous Period
    • dinosaurs reached their peak in size and distribution.
    • the continents were close to their present locations.
  • Cenozoic Era
    • “Age of Mammals”, translates to “ recent life”, started 65 million years ago and continues up to the present.
  • Periods of Cenozoic era
    1. Tertiary Period
    2. Quarternary Period
  • Tertiary Period
    • Earth’s climate was generally warm and humid.
    • MAMMALS - primate EVOLVED INCLUDING HUMAN ANCESTORS
    • modern rainforest and grassland appeared
    • flowering plants and insects were widespread
  • Quarternary Period
    • EARTH'S CLIMATE COOLED leading to a series of ice age
    • created land and bridges between continents allowing land animals to move to new areas
    • mammals like WOOLY AND MAMMOTHS, adapted to COLD by having thick fur and very large size
  • Epochs
    • Smallest division of the geologic time scale.
  • Epochs of the Quarternary Period
    1. Pleistocene Epoch - hominid line continues to evolve during this period
    2. Holocene Epoch - "Age of Man." the climate has seen some warming and cooling and large mammals have gone extinct. Humans have possibly caused the holocene extinction.