Bio 116 exam 1 Already Passed!!

What are the 8 characteristics of life? - 1. Common chemical components (proteins, nucleic acids, etc) 2. Composed of Cell(s) 3. Be able to grow 4. Cells obtain energy from environment 5. Have universal genetic code 6. Similar genes 7. Evolving populations 8. Maintain homeostasis......must have all 8 to be considered living What is the scientific method? - Make observations, ask questions, make a testable hypothesis, make a prediction, conduct experiment..........results may lead to more questions thus more experiments What is a scientific theory? - a far-reaching explanation supported by such wide body of evidence that it's considered scientific fact; start as hypothesis that goes through many tests with no significant contradictory evidence Approximately how old is the Earth and how long ago did life first appear? - Earth = 4.6 billion years old and the oldest life is 3.8 billion years old *humans developed about 500,00 years ago What is stratigraphy and how is it used as a dating method? - The study of layers; uses rock strata (layers) to get a relative age of something; higher strata = younger and lower strata = older *Fossils of similar organisms found in widely separated places *Certain fossils found in older strata...certain fossils found in younger strata *Fossils in younger strata are similar to extant organismsRadiometric Dating***** - What signifies time period divisions? What drives these causes? - Time period divisions come from BIG changes on Earth (mass extinction); Massive glaciation, climate changes, volcanoes, extraterrestrial events, and oxygen concentration drives these big changes