17 terms

Campbell Biology - Chapter 25

The History of Life on Earth
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macroevolution
evolution on a large scale extending over geologic era and resulting in the formation of new taxonomic groups
protocells
droplets with membranes that maintained an internal chemistry different from that of their surroundings, nonliving structures that are believed to have evolved into prokaryotes
ribozymes
RNA molecules that function as enzymes
radiometric dating
the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products
half-life
the time required for one half of the atoms of a radioisotope to emit radiation an decay products
geologic record
The division of Earth's history into time periods, grouped into three eons—Archaean, Proterozoic, and Phanerozoic—and further subdivided into eras, periods, and epochs.
stromatolites
Rock made of banded domes of sediment in which are found the most ancient forms of life: prokaryotes dating back as far as 3.5 billion years.
endosymbiont theory
the theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.
serial endosymbiosis
supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events
Cambrian explosion
A burst of evolutionary origins when most of the major body plans of animals appeared in a relatively brief time in geologic history; recorded in the fossil record about 545 to 525 million years ago.
plate tectonics
the branch of geology studying the folding and faulting of the earth's crust
mass extinction
event in which many types of living things become extinct at the same time
Pangaea
the name of the single landmass that broke apart 200 million years ago and gave rise to today's continents
adaptive radiation
the development of many different forms from an originally homogeneous group of organisms as they fill different ecological niches
heterochrony
Evolutionary change in the timing or rate of an organism's development.
paedomorphosis
The retention in an adult organism of the juvenile features of its evolutionary ancestors.
homeotic genes
Any of the genes that control the overall body plan of animals by controlling the developmental fate of groups of cells.