1. The History of Life
Chapter 17

2. Fossils and Ancient Life
Paleontologists: scientist who study fossils

3. 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.

4. Radioactive Dating absolute ages to rocks
Half-life: the length of time required for half of the radioactive atoms in a sample to decay

5. 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)

7. 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.

8. 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

9. Geologic Time Scale

10. Patterns of Evolution
Macroevolution: large-scale evolutionary patterns and processes that occur over long periods of time

11. Adaptive Radiation
How a single or a small group of species has evolved through natural selection
Created variation in organisms

12. Convergent Evolution
unrelated organisms come to resemble one another

13. Coevolution
An evolutionary change in one organisms may be followed by a change in another organism

14. Evolutionary Classification
Phylogeny: the sequence of events involved in the evolution of a species, genus, etc.

15. Finding Order in Diversity
Binomial Nomenclature: each species is assigned a two-part scientific name
Always written in italics

16. Linnaeus’s System of Classification
Hierarchical system of classification includes seven levels: (page 450)
Species
Genus
Family
Order
Class
Phylum
kingdom