Changes over time Flashcards
Charles Darwin
a scientist that traveled to the galapagos islands to learn more about the diversity of living things, remains of ancient organisms, and characteristics of organisms
species
a group of similar organisms that can mate with each other and produce fertile offspring
fossil
preserved remains or traces of an organism that lived in the past
adaptation
a trait that helps an organism survive and reproduce
what did darwin hypothesize when he saw that the animals on the galapagos islands were different than those on the mainland
the species gradually changed over many generations and became better adapted to the new conditions
evolution
the gradual change in a species
scientific theory
a well-tested concept that explains a wide range of observations such as survival of the fittest
natural selection
the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species
variation
any difference between individuals of the same species
what factors affect the process of natural selection (3)
overproduction, competition, variation
what did darwin think natural selection was doing
he thought that over time, n.s. would lead to change. helpful variations may gradually accumulate in a species while unfavorable ones may disappear
what things provide evidence that organisms changed over time (3)
fossils, patterns of early development, similar body structures
homologous structures
similar structures that related species have inherited from a common ancestor
what do scientists put together to see evolutionary relations among species (5)
DNA, protein structure, fossils, early development, body structure
branching tree
a diagram that shows how scientists think different groups of organisms are related
how can a new species form
when a group of individuals remains isolated from the rest of its species long enough to evolve different traits
how do fossils form
when organisms that die become buried in sediments
petrified fossils
fossils that form by having minerals and water soak into rock
mold
hollow space in the sediment in the shape of an organism
cast
copy of the shape of the organism that made the mold
how can scientists find a fossil’s age (2)
relative dating, radioactive dating
relative dating
determines which of two fossils is older
radioactive dating
determines actual age of fossil
radioactive elements
unstable elements that decay, break down, into different elements
half life
the time it takes for half of the atoms in a sample to decay
fossil record
the millions of fossils that scientists have collected
geologic time scale
calendar of earths history
extinct
if no members of a species are alive
gradualism
theory that evolution occurs slowly but steadily
punctured equilibria
theory that species evolve quickly during relatively short periods of time
