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History of Life on Earth definitions Flashcards

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History of Life on Earth definitions
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  • Biogeography

    The study of how species and ecosystems are distributed geographically and through geological time, influenced by factors like continental drift and evolutionary forces.
  • Fossil Record

    A chronological collection of preserved remains or imprints of organisms from past geological ages, providing insights into the history of life on Earth, though incomplete and biased.
  • Radiocarbon Dating

    A method to determine the age of fossils by measuring the ratio of carbon-12 to carbon-14 isotopes, utilizing the known half-life of carbon-14 to estimate the time since the organism's death.
  • Stromatolite

    Layered structures formed by cyanobacteria through sediment trapping and binding, dating back billions of years, and still existing today.
  • Cyanobacteria

    Photosynthetic bacteria that form stromatolites, contribute to oxygen production, and are among the oldest known fossils, often misnamed as blue-green algae.
  • Half Life

    The time required for half of a radioactive substance to decay, used to date fossils by measuring remaining isotopes.
  • Plate Tectonics

    The theory that Earth's crust is divided into large, solid plates that float on the hot mantle, causing continents to drift and influencing the distribution and evolution of species over time.
  • Mantle

    A layer of the Earth beneath the crust, composed of semi-solid rock, which allows tectonic plates to move and is crucial for continental drift.
  • Continental Drift

    The gradual movement of Earth's continents over geological time, leading to the separation and collision of landmasses, influencing the distribution and evolution of species.
  • Pangaea

    A supercontinent that existed during the late Paleozoic and early Mesozoic eras, comprising all Earth's landmasses before they separated due to continental drift.
  • Mass Extinction

    A mass extinction is a rapid event where a significant percentage of Earth's species die out in a short geological period, drastically reshaping ecosystems and evolutionary pathways.
  • Adaptive Radiation

    The process by which organisms rapidly diversify into new forms, often in response to environmental changes that create new ecological niches and shift evolutionary pressures.
  • Cambrian Explosion

    A period around 541 million years ago marked by a rapid diversification of life forms, resulting in the emergence of most major animal phyla in a relatively short geological time span.
  • Symbiogenesis

    The process where two distinct organisms merge to form a new organism, often leading to significant evolutionary changes, such as the origin of eukaryotic cells from prokaryotic cells.
  • Punctuated Equilibrium

    Evolutionary changes occur rapidly during short periods, punctuating long intervals of little change, leading to significant species diversification in brief bursts.