Chapter 7-8 Flashcards
Species
A group of organisms that can mate with one another to produce fertile offspring.
Adaption
A characteristic that helps an organism survive and reproduce in its environment.
Evolution
The process in which populations gradually change over time.
Fossil
The remains or imprints of once-living organisms found in layers of rock.
Fossil record
A timeline of life.
Trait
A genetically determined characteristic.
Selective breeding
The process in which humans select which plants or animals to reproduce based on certain desired traits.
Natural selection
The process by which organisms that are better adapted to their environment survive and reproduce more successfully than less well adapted organisms do.
Generation time
The average time between one generation and the next.
Speciation
The formation of new species as a result of evolution.
Relative dating
Any method of determining whether an event or object is older or younger than other events or objects.
Absolute dating
Any method of measuring the age of an object or event in years.
Geologic time scale
The calendar scientists use to outline the history of life on earth.
Extinct
Describes a species that has died out completely.
Plate tectonics
The theory that explains how large pieces of the Earth’s outermost layer, called tectonic plates, move and change shape.
Precambrian time
The time from the formation of Earth 4.6 billion years ago to about 542 million years ago.
Paleozoic ear
Began at about 542 million years ago and ended about 251 million years ago.
Mesozoic era
Began about 251 million years ago and lasted about 185.5 million years ago.
Cenozoic era
Began about 65 million years ago and continues today.
Primates
A group of mammals that includes humans, apes, monkeys, and lemurs.
Hominids
Includes only humans and their human-like ancestors.
Homo sapiens
The species of hominids that includes modern humans and their closest ancestors and that first appeared about 100,000 to 160,000 years ago.