Ch 7-8 Flashcards
Species
A group of organisms that are closely related and can mate to produce fertile offspring.
Evolution
The process in which inherited characteristics within a population change over generations such that new species sometimes arise.
Fossils
The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock.
Fossils record
A historical sequence of life indicated by fossils found in layers of the earths crust.
Trait
A genetically determined characteristic.
Selective breeding
The human practice of breeding animals or plants that have certain desired traits.
Natural selection
The process by which individuals that are better adapted to their environment survive and reproduce more successfully that less well adapted individuals do.
Generation time
The period between the birth of one generation and the birth of the next generation.
Speciation
The formation of new species as a result of evolution.
Adaption
A characteristic that improves an individual’s ability to survive and reproduce in a particular environment.
Relative dating
Any method of determining weather 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 standard method used to divide the Earths long natural history into manageable parts.
Extinct
Describes a species that has died out completely.
Plate tectonics
The theory that explains how large pieces of the Earths outermost layer, called tectonic plates, move and change shape.
Precambrian time
The period in the geologic time scale from the formation of the earth to the beginning of the Paleozoic era, from about 4.6 billion to 542 million years ago.
Paleozoic era
The geologic era that followed Precambrian time and that lasted from 542 million to 251 million years ago.
Mesozoic era
The geologic era that lasted from 251 million years ago to 65.5 million years ago, also called age of reptiles.
Cenozoic era
The most recent geologic era, beginning 65 million years ago, called age of mammals.
Primate
A type of mammal characterized by opposable thumbs and binocular vision.
Hominid
A type of primate characterized by bipedalism, relatively long lower limbs, and lack of a tail.
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.
