Section 5-1
A group of similar organisms that can mate with each other and produce fertile offspring.
What is a species?
The preserved remains or traces of an organism that lived in the past.
What is a fossil?
Similar structures that related species have inherited from a common ancestor.
What are homologous structures?
If two fossils are found in the wall of a cliff, how could you tell which fossil is older?
The fossil further down the canyon wall is older, and the fossil closer to the top is younger.
Any difference between individuals of the same species.
What is a variation?
A trait that helps an organism survive and reproduce.
What is an adaptation?
A type of fossil that forms when minerals replace the remains of an organism buried in sedimentary rock.
What is a petrified fossil?
This is a diagram that shows how scientists think different groups of organisms are related.
What is a branching or phylogenetic tree?
Give an example of how the preserved remains of an organism can be formed?
Organisms falling into tar pits and becoming encased in amber, creatures being frozen in ice, etc.
If no members of a species are still alive.
What is extinct?
The gradual change in a species over time.
What is evolution?
Scientists use this to determine which of two fossils is older.
What is relative dating?
Comparing the skeletal systems horses, zebras and donkeys to determine if they are related is an example of noticing similarities in this.
What is body structure?
Most fossils are found in this type of rock.
What is sedimentary rock?
Any difference between individuals of the same species.
What is a variation?
A well-tested concept that explains a wide range of observations.
What is a scientific theory?
Scientists use this to determine the ACTUAL age of a fossil using its radioactive elements.
What is absolute dating?
When scientists compare the genes of different species to determine how closely related they are, they are noticing the similarities in what?
DNA
How are most fossils formed?
When organisms that die become buried in sediments.
When does a new species form?
When a group of individuals remains separated from the rest of its species long enough to evolve different traits.
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.
What is natural selection?
The millions of fossils that scientists have collected.
What is the fossil record?
Scientists sometimes look at organisms before they are born as evidence of evolution. Why?
To compare similarities in early development.
Scientists use the __________________ of a radioactive element to determine the age of a fossil.
What is half-life?
The name of the supercontinent before continental drift separated it into separate continents.
What is Pangaea?