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science ch. 7

science ch 7

TermDefinition
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
Created by: tmanfred