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AP Biology Ch 24-25

AP Biology Chapter 24-25: The History of Life on Earth

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
Created by: Hajra Maqsoos