Term |
Definition |
Stromalites |
the first single-celled organisms and the oldest known fossils; rocks formed by the accumulations of sedimentary layers on bacterial mats. |
oxygen revolution |
from 2.7 to 2.3 billion years ago caused the extinction of many prokaryotic groups.
|
endosymbiotic theory |
proposes that mitochondria and plastids (chloroplats and related organelles) were formerly small prokaryotes living within larger host cells. |
endosymbiont |
a cell that lives within a host cell. |
serial endosymbiosis |
supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events. |
the "snowball Earth hypothesis" |
suggests that periods of extreme glaciation confined life to the equational region or deep sea vents from 750 to 580 million years ago. |
Ediacaran biota |
an assemblage of larger and more diverse soft-bodied organisms that lived from 575 to 535 million years ago. |
Cambrian explosion |
the sudden appearance of fossils resembling modern animal phyla in the Cambrian period (535 to 525 million years ago). |
Permian extinction |
the boundary between the Paleozoic and Mesozoic eras 251 million years ago. |
Cretaceous mass extinction |
65.5 million years ago separates the Mesozoic from the Cenozoic; caused the extinction of the dinosaurs
|
adaptive radiation |
the evolution of diversely adapted species from a common ancestor. |
heterochrony |
an evolutionary change in the rate or timing of developmental events |
paedmorphosis |
the rate of reproductive development accelerates compared with somatic development. |
homeotic genes |
determine such basic features as where wings and legs will develop on a bird or how a flower's parts are arranged. |
hox genes |
a class of homeotic genes that provide posotional information during development. |
binomial |
the two part scientific name of a species. |
epithet |
unique for each species within the genus. |
taxon |
the taxonomic unit at any level of hierarchy. |