Antiquity of Life Flashcards
How old is the Earth?
Our own solar system formed 4.55-4.56 billion years ago.
Our universe is about 13.7 billion years ago
What was Primitive Earth’s atmosphere consisted of?
Methane, ammonia, water vapor, and a negligible amount of free oxygen
To oxidize substances means?
To remove one or more electrons from an atom, ion, or molecule
The early atmosphere was highly reducing means?
capable of gaining electrons and forming more complex molecules
Autotrophs
An organism capable of making its own food from inorganic sulfur and iron compounds
Heterotrophs
Consuming organic molecules
Continental drift
The continents are constantly rearranging themselves
Plate tectonics
Movement of large plates of Earth’s crust due to activity at spreading centers and subduction zones.
When first organisms appeared on earth?
3.5 billion years ago
Four great eras of the geological time scale
Precambrian (oldest), Paleozoic, Mesozoic, and Cenozoic (we are in the Quaternary period of Cenozoic era)
Dating Fossil:
Relative Dating
Absolute Dating
RD: Deeper sedimentary layers formed earlier and their fossils are older than those found in shallow layers of rock
AD: Radiometric dating dendrochronology and racemization
Archaea
One of three major domains that contains more simple cells (prokaryotes)
Dendrochronology
A type of absolute dating technique that relies on the fact that trees have annual growth rings that reflect the age of the tree (one ring is produced each year).
Eukarya
One of three major domains that contains complex cells with a nucleus and an array of organelles that perform different functions within the cell (eukaryotes).
Eukaryote
Member of the Eukarya that have complex cells with a nucleus and an array of organelles that perform different functions within the cell.
Fossil
Preserved remnants of organisms (e.g., bones and teeth) or whole organisms embedded in amber, acid bogs and tar pits, or anywhere bacteria can’t decompose a dead body. Fossils can be found in other forms such as an animal’s footprint.
Geological time scale
classification of different periods in Earth’s history that is used to divide fossils into age groups. Four great eras of the geological time scale are Precambrian, Paleozoic, Mesozoic, and Cenozoic eras.
Heterotroph
An organism unable to make its own food, and therefore must consume organic molecules to gain energy.
Half-life
A radioisotope’s half-life is the amount of time it takes for one-half of the parental atom population to decay into daughter atoms.
Isomer
Isomers are compounds with the same formula, but each of them have a different arrangement of atoms in the molecule and different properties.
Isotope
Isotopes of an element have the equal numbers of protons, but different numbers of neutrons. Different isotopes have different, but predictable stabilities. Radioactive isotopes’ nuclei decay at predictable rates (unique for each isotope) and give off energy and atomic particles.
Pangaea
The supercontinent from about 250 million years ago where all of the landmasses were joined. Pangaea did not start to break apart until about 180 million years ago.
Prokaryote
Any of the typically unicellular microorganisms that lack a distinct nucleus and membrane-bound organelles
Reduction
A chemical reaction that involves the gaining of electrons and therefore lowering the oxidation state of the element that gains electrons.
