Chapter 6 Flashcards
What kind of traits can be acted upon by natural selection
Inherited traits
What are differences between members of the same species called
Variation
In order for a new species to form what has to happen first
Geographic isolation
What are fossils
Preserved remains or traces of an organism that lived in the past
How do most fossils form
Organisms die and become buried in sediment
What is the difference between radioactive and relative dating
Relative- determining which of two fossils are older
Radioactive – determining the actual age of fossils
What are you comparing when performing relative dating
Their placement in the layers of rock
Defined the word extinct
No members of that species are still alive
What is the difference between gradualism and punctuated equilibria
Gradualism – evolution occurs slowly but steadily
Punctuated equilibria – small period of big changes and then a small period of no changes and repeats
What theory is supported by fossil records that show no intermediate forms for long periods of time
Punctuated equilibria
What term refers to similar structures that related species inherit from a common ancestor
Homologous structures
List the four types of evidence that scientist use to determine evolutionary relationships
Fossils, DNA, body structure, similarities in early development
What is a branching tree
A diagram that shows how scientists think different groups of organisms are related
What difference did Darwin observe among the finches on the Galapagos islands
Beak size and shape
What is a trait that helps an organism to survive and reproduce called
Adaptation
Explain the concept of natural selection
Process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other numbers of the same species
How does natural selection lead to evolution
Helpful variations may gradually accumulate in a species while unfavorable ones may disappear
What term refers to a species creating more offspring that can survive
Overproduction
What is the difference between a mold and a cast
Mold – a hollow space in sediment in the shape of an organism or part of an organism
Cast– A copy of the shape of the organism that made the mold
In sedimentary rock where are the oldest fossils found
Bottom
What is the first span of time in the geologic time scale
Precambrian
Define the word species
A group of similar organisms that can mate with each other and produce fertile offspring
In what type of rock are most fossils formed
Sedimentary
Define the term half-life
The time it takes for half of the atoms in a sample to decay of a radioactive element
How is a scientific theory different from the term theory used everyday conversation
Scientific – well tested concept that is generally accepted as true
Theory – guess
What is a mass extinction
When many types of organisms become extinct at one time
What could cause a mass extinction
Climate change, astroid, volcanic eruptions
