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science ch. 7
science ch 7
Term | Definition |
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Darwin | Charles Darwin is one of the best-known scientists of all time. His theory of evolution was a major leap forward in human understanding. It explains and unifies all of life science. |
evolution | a change in the inherited traits of organisms over time |
Galápagos Islands | can be found 966 kilometers (about 600 miles) off the west coast of South America |
natural selection | the process in which living things with beneficial traits produce more offspring |
theory of evolution by natural selection | the process by which organisms change over time as a result of changes in inheritable physical or behavioral traits |
absolute dating | determines about how long ago a fossil organism lived |
fossil | the preserved remains or traces of organisms that lived during earlier ages |
molecular clock | the average rate at which a species' genome accumulates mutations, used to measure their evolutionary divergence |
paleontologist | A scientist who studies fossils to learn about the evolution of living things |
relative dating | determines which of two fossils is older or younger than the other but not their age in years |
vestigial structure | These are body parts that are no longer used but are still present in modern organisms |
allele frequency | The frequency of an allele is the number of copies of that allele divided by the total number of alleles for the gene in the gene pool. |
coevolution | When one of the two species evolves new traits, the other species may evolve matching traits |
convergent evolution | Sometimes two species evolve the same traits |
gene flow | the movement of genes into or out of a gene pool |
gene pool | All the genes in all the members of a population |
genetic drift | a random change in allele frequencies |
macroevolution | Evolution that occurs over a long period of time |
microevolution | Evolution that occurs over a short period of time |
population | a group of organisms of the same species that live in the same area |
speciation | The evolution of a new species |
Cenozoic Era | the age of mammals |
extinction | when a species completely dies out |
geologic time scale | It divides Earth’s history into eons, eras, and periods. |
Last Universal Common Ancestor (LUCA) | Scientists think that one cell gave rise to all of the following life on Earth |
mass extinction | the majority of species die out |
Mesozoic Era | This era is known as the “age of dinosaurs ” It is divided into three periods. |
Paleozoic Era | lasted from 544 to 245 million years ago. It is divided into six periods. |
Precambrian | the first major division of Earth’s history . It covers the time from Earth’s formation 4.6 billion years ago to 544 million years ago |