History of Life Flashcards
Astrobiologist
A scientist who searches for evidence of life on other worlds.
Autotroph
An organism that makes its own food by manufacturing organic compounds such as carbohydrates, that it uses as source of energy and nutrients.
Banded iron formation
A sedimentary rock composed of alternating thin layers formed of iron oxide mineals and silica-rich minerals, precipitated from seawater when oxygen, produced by cyanobacteria, reacted with iron dissolved in seawater. Banded iton formations mark the rise of oxygen in the atmosphere.
Biogeochemical cycle
A pathway through which a chemical element or molecule moves between the biologic and environmental components of an ecosystem.
Biosphere
The sum total of all living organisms and the organic matter they produce.
Cambrian explosion
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Chemoautotroph
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Chemofossil
The chemical remains of organic compounds made by an organism while it was alive.
Cyanobacteria
A group of microorganisms that produce oxygen adn carbohydrates by photosynthesis. It is believed that photosynthesis orginated in cyanobacteria.
Ecosystem
An organizational unit composed or organisms and geologic components that function in a balanced, interrelated fashion.
Evolution
The process by which organisms change through time, driven by the process of natural selection.
Evoluationary radiation
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Extremophile
A microbe that lives in environments that would kill any other organism.
Gene
A large molecule within the cells of every organism encoding all the information that determines what the organism will look like, how it will live and reproduce, and how it differs from all othe organisms.
Geobiology
The study of how organisms have influences that been influenced by Earth’s environment.
Habitable zone
In the context of astronomy, a habitable zone is the space surrounding a star where water is stable as a liquid. If a planet is within a habitable zone, there is a chance that life could exist there.
Heterotroph
An organism that gets its food by feeding directly or indirectly on autotrophs.
Metabolism
The process that all organisms use to convert inputs to outputs.
Microbial mat
A layered microbial community commonly occurring in tidal flats, hypersaline lagoons, and thermal springs..
Microfossil
A fossil that can only be studied microscopically. The oldest microfossils that preserve possible morphologic evidence for life arre tiny threads similar in size and appearnace to modern microbes, encased in chert.
Natural selection
The adapation of populations of organisms to new environments. Natural selection is responsible for the development of new species.
Photosynthesis
The process by which organisms such as green plants and algae use energy from sunlight to convert water and carbon dioxide to carbohydrates and oxygen.
Red bed
A bed of sandstones and shales that is red because of the presence of iron oxide cement that bidns the grains together. The presence of red beds around 2.7-2.1 Ga indicates that oxygen must have been present in the atmosphere to precipitate the iron oxide cements.
Respiration
The process that allows an organism to release the energy stored within carbohydrates. All organisms use oxygen to burn, or respire, carbohydrates to creat energy.
