Term | Definition |
Protocells (protobionts) | Droplets with membranes that maintained an internal chemistry different from that of their surroundings |
Ribozymes | RNA catalysts; some can make complementary copies of short pieces of RNA |
Endosymbiont theory | relationship in which one organism lives inside of another and both benefit; thought to be the process that gave rise to organelles like mitochondria and chloroplasts |
Mass extinction | Large numbers of species become extinct throughout Earth |
Adaptive radiations | Periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles |
Heterochrony | An evolutionary change in the rate or timing of developmental events |
Homeotic genes | Master regulatory genes that determine such basic features as where a pair of wings and a pair of legs will develop on a bird or how a plant's flower parts are arranged |
Hox genes | Provide positional information in an animal embryo |
Abiotic Synthesis | the process of chemical evolution forming complex organic molecules from inorganic materials or simple organic molecules |
Stanley Miller and Robert Urey | scientists who recreated the environment of early Earth to show that organic molecules like amino acids could form by combing water vapor |
RNA World hypothesis | hypothesis that RNA served as the genetic material on early Earth rather than DNA |
Prokaryote | organisms that lack a membrane-bound nucleus and organelles (bacteria and archaea) |
cyanobacteria | type of bacteria that can carry out photosynthesis |
4 stages of cell synthesis | 1. simple organic compounds 2. abiotic synthesis of macromolecules 3. Protocells (protobionts) 4. Self-replicating dna |
Cambrian explosion | Sudden increase in diversity of animal phyla. mainly invertebrates |
First atmosphere on Earth | very hot with water vapor |
Fossil record | shows changes in organisms including extinct. shows hot groups arose from sedimentary strata which reveal the RELATIVE ages of fossils. absolute ages are estimated with radiometric dating |