Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chapter 12
The History of Life
| Term | Definition |
|---|---|
| relative dating | estimates the time during which an organism lived by comparing the placement of fossils of that organism with the placement of fossils in other layers of rock |
| radiometric dating | a technique that uses the natural decay rate of unstable isotopes found in materials in order to calculate the age of that material |
| isotope | atoms of an element that have the same number of protons but a different number of neutrons |
| half-life | the amount of time it takes for half of the isotope in a sample to decay into a different element |
| index fossil | a fossil of an organism that existed only during specific spans of time over large geographical areas |
| geological time scale | a representation of the history of Earth |
| era | lasts tens to hundreds of millions of years and consists of two or more periods |
| period | the most commonly used units of time on the geological time scale, lasting tens of millions of years; associated with a particular type of roc |
| epoch | the smallest units of geologic time and lasts several million years |
| nebula | a cloud of gas and dust in space |
| ribozyome | RNA molecules that can catalyze specific chemical reactions |
| cyanobacteria | bacteria that can carry out photosynthesis |
| endosymbiosis | a relationship in which one organism lives within the body of another, and both benefit from the relatioship |
| Paleozoic | the era in which multi-cellular organisms first appeared in; began 544 million years ago |
| Cambrian explosion | the earliest period of the Paleozoic era; involved the evolution of a huge diversity of animals |
| Mesozoic | this era is called the Age of Reptiles (dinosaurs roamed); began 248 million years ago and ended 65 million years ago |
| Cenozoic | the era containing two periods in which mammals evolved and diversified |
| primate | the category of mammals with flexible hands and feet, forward-looking eyes, and enlarged brains relative to body size |
| prosimian | the oldest living primate group; most are small and active at night |
| anthropoid | humanlike primates |
| hominid | walk upright, have long lower limbs, thumbs that oppose the other four fingers, and relatively large brains |
| bipedal | animals that can walk on two legs |
Created by:
tuohybio1415
Popular Biology sets