The History of Life Chapter 17
Fossils and Ancient Life Paleontologists: scientist who study fossils
Relative Dating The age of a fossil is determined by comparing its placement with that of fossils in other layers of rock Index Fossils: used to compare relative age of fossils.
Radioactive Dating absolute ages to rocks Half-life: the length of time required for half of the radioactive atoms in a sample to decay
Formation of Earth 4.6 billion years old Pieces of cosmic debris collided with one another Elements rearranged themselves according to density Conditions were toxic, hot, and anaerobic (no oxygen)
Miller and Urey Experiment Experiment that simulated the conditions of Early Earth: They added hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water with an electric spark (simulating lightning) They produced organic molecules…the stuff life is made of. It is thought life could have arisen in this manner.
Evolution of Life on Earth: Order of appearance: Prokaryotes (no nucleus or organelles - Bacteria) Eukaryotes (nucleus and organelles ) Multicellular organisms (many cells) Invertebrate animals (no backbone) Vertebrate animals (backbone) Dinosaurs and Small Mammals Humans
Geologic Time Scale
Patterns of Evolution Macroevolution: large-scale evolutionary patterns and processes that occur over long periods of time
Adaptive Radiation How a single or a small group of species has evolved through natural selection Created variation in organisms
Convergent Evolution unrelated organisms come to resemble one another
Coevolution An evolutionary change in one organisms may be followed by a change in another organism
Evolutionary Classification Phylogeny: the sequence of events involved in the evolution of a species, genus, etc.
Finding Order in Diversity Binomial Nomenclature: each species is assigned a two-part scientific name Always written in italics
Linnaeus’s System of Classification Hierarchical system of classification includes seven levels: (page 450) Species Genus Family Order Class Phylum kingdom