Chapter 17 - The History of Life Flashcards
What does the fossil record provide?
evidence about the history of life on Earth
What does the fossil record show in regards to evolution?
how different groups of organisms, including species, have changed over time
How is the age of a fossil determined through relative dating?
By comparing its placement with that of fossils in other layers of rock
Which rock layer is older, the top or bottom?
the bottom
What are index fossils?
fossils used to compare the relative ages of fossils
What is a half-life?
the length of time required for half of the radioactive atoms in a sample to decay
What is radioactive dating?
the use of half-lives to determine the age of a sample
How is the age of a fossil determined through radioactive dating?
Scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains
What is the half-life of Carbon-14?
5730 years
What are the eras following the Precambrian time?
Paleozoic, Mesozoic and Cenozoic respectively
What period are we currently in?
Quaternary
What is macroevolution?
large-scale evolutionary patterns and processes that occur over long periods of time
What are the 6 important topics in macroevolution?
extinction, adaptive radiation, convergent evolution, coevolution, punctuated equilibrium, and changes in developmental genes
What is adaptive radiation?
when a single species or a small group of species has evolved into diverse forms that live in different ways (ex. finches)
What is convergent evolution?
unrelated organisms come to resemble one another (ex. shark, penguins and dolphin)
