Term | Definition |
absolute dating | tells you when the fossil was formed by using radioactive elements found in rocks and fossils such as uranium |
adaptation | an inherited trait that gives an organism an advantage in its environment; can be a physical characteristic such as fur color or an internal characteristic such as resistance to harsh weather condition |
ancestor | an early form of an organism from which later forms descend |
Charles Darwin | British naturalist who came up with the theory of natural selection |
common ancestor | an important theory of natural selection; i.e. through this theory, we can look at fossils of ancient algae and see how they adapted to become modern plants |
Cretaceous Extinction | around 65 million years ago and dinosaurs and over half of all living species at the time became extinct; no one knows the real reason why; scientists hypothesize that it is a meteorite |
Darwin's Theory | giraffes had traits for long necks and short necks; since trees were tall, the short neck giraffes would starve to death, leaving the tall neck giraffes to reproduce |
evolution | when organisms change to be more fit for their environment |
fossil record | the information about fossils found in a particular area; scientists use these to examine periods of time in which different species lived and died; they develop an overview of Earth's history |
fossils | you can use these to find a common ancestor; many _______ showed that tow species with a common ancestor can develop differently in different locations |
isolation | when organisms in a species will be _______ from others; in different environments, the species will adapt to their environments, which create different variations |
Lamarck's theory | over time, giraffes stretched their necks to reach tall trees |
mass extinction | a period of time where huge numbers of species become extinct in a very short time |
natural selection | this states that individuals in a species that have the best traits to survive in an environment will reproduce, while the ones with less desirable traits will not; based off key principles |
overproduction | many animals produce more offspring than they can support; offspring that are not the fittest will die off or get eaten, keeping the population at a regular level; i.e. when fish lay eggs, they lay hundred, but many of the eggs do not hatch |
Permian Extinction | occurred around 250 million years ago, and 90% of the species living the ocean became extinct and many land animals disappeared; scientists think it was because two land masses joined together and changed the climate |
relative dating | used to find the age of fossils; one fossil is compared to another, which tells if one fossil was formed before another; you look at layers of rock and minerals/materials |
selection | the evolution of new species from an existing species; can occur when environments change drastically or gradually |
similarities in development | many animals look similar in early stages of life inside the womb or egg; as animals age, they begin to look different as they get older |
speciation | the evolution of new species from an existing species; can occur when environments change drastically or gradually |
variation | mutations that are desirable (and sometimes undesirable) are passed down from parent to offspring, making individuals within a species different in some ways; this can help or hurt survival rates |
vestigial organ/structure | physical structures that were fully developed and functional in an ancestral group of organisms but are reduced and unused in later species; can also be bones that are not used; your appendix and tailbone |