All terms in this list:
mutation: a random change in an organisms' DNA, which results in that organism having a different trait or characteristic
trait: a characteristic that an organism has (examples: brown fur, blue eyes, long neck, etc.)
law of superposition: the law which states that the further down you dig, the older the rocks (and fossils) are.
natural selection: the slow process by which organisms adapt to new environmental pressures, sometimes referred to as "survival of the fittest."
evolution: Developed by Charles Darwin, this theory states that organisms change very slowly over time to become more advanced new species. This process is driven by natural selection.
ancestor: An organism from which another has descended
descendent: an organism that has descended from an ancestor
common ancestor: When two organisms evolved from the same organism we call that organism their ___________ ___________.
vertebrate: An organism that has a backbone
invertebrate: An animal that has no backbone
Cambrian Explosion: A period of time during the Paleozoic Era when many marine invertebrates evolved and appeared in the fossil record for the first time
geologic time scale: How scientists measure Earth's long history
Paleozoic Era: "Ancient life." This was the first era after Precambrian time, when many group of animals were evolving, including invertebrates, and the first vertebrates
Mesozoic Era: "Middle life," The Age of Reptiles, when dinosaurs evolved and became extinct at the end
Cenozoic Era: "Recent Life," The Age of Mammals, characterized by several dramatic changes in climate and periodic ice ages
Jurassic: The second period of the Mesozoic
Triassic: The first period of the Mesozoic, dinosaurs and mammals appear in the fossil record for the first time
Cretaceous: The third and final period of the Mesozoic Era which ended in a mass extinction
Permian extinction: The largest mass extinction of Earth's history, took place at the end of the Paleozoic, over 95% of marine life became extinct
Periods: Eras are broken down into smaller chunks called ___________.
epochs: Periods are broken down into smaller chunks of time called ____________.
mass extinction: When a large number of species become extinct within a relatively short period of time.
environmental pressure: Any factor that makes it more difficult for organisms to survive (limited food, water, space, predators, etc.)
adaptation: A characteristic that helps an organism survive the process of natural selection
Pangaea: giant supercontinent that broke apart during the Mesozoic Era.
amphibian: an animal that lives part of its life on land and part under water
reptile: a vertebrate with scaly skin, that lays eggs, some have a shell
mammal: a warm-blooded vertebrate that feeds its young milk (examples: mice, humans, tigers, bears, horses, elephants, sloths, etc.)
Tertiary Period: The first period in the Cenozoic Era
Quaternary: The second period of the Cenozoic Era, the one we are living in now
radioactive dating: a method scientists use to figure out a rock or fossils absolute age
relative age: The age of a rock or fossil compared to other rocks or fossils
absolute age: the exact number of years since a rock or fossil formed
index fossil: fossils of widely distributed organisms who lived during a known amount of time