Home > Flashcards > Geology > Chap.18 Evolution

Details Title: Chap.18 Evolution Description: The theory and its supporting evidence Total Flash Cards: 30 Created: 02/24/2006 23:24:17	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Allele Definition Alternative form of a single gene controlling different versions of the same trait. Term Allopatric speciation Definition Model for the evolution of a new species from a small, geographically isolated part of a larger parent population. Term Analogous structure Definition Body part, such as wings of insects and birds, that serves the same function but differs in structure and development. Term Artificial selection Definition The practice of selectively breeding plants and animals for desirbale traits. Term Body Fossil Definition The actual remains of an organism, such as bones, teeth, shells, and rarely the soft parts. Term Chromosome Definition Double-stranded, helical molecule of deoxrybonucleic acid (DNA); specific segments of chromosomes are genes. Term Cladistics Definition A type of analysis of orgainisms in which they are grouped together on the bases of derived as opposed to primitive characteristics. Term Cladogram Definition A diagram that shows the probable evolutionary relationships among members of a clad. A group of organisms including their most recent common ancestor. Term Convergent EvOlUtIoN Definition The development of similar features in two or more distantly relating groups of organisms resulting from adapting to a comparable lifestyle. Term Deoxyribonucleic Acid DNA Definition The chemical substance of which chromosomes are composed; the genetic material in all organisms. Term Divergent Evolution Definition The diversification of a species into two or more descendant species. Term Fossil Definition Remains or traces of prehistoric organisms preserved in rocks. Term Gene Definition A specific segment of a chromosome constituting the basic unit of heredity. Term Homologous structure Definition Body part in different organisms that has a similar structure, similar relationships to other structures and similar development but does not necessarily serve the same function. For example, forelimbs in whales, dogs, and bats. Term Inheritance of acquired characteristics Definition Jean Baptist de Lamarck's mechanism for evolution; holds that characteristics acquired during an individual's lifetime can be inherited by descendants. Term Mass extinction Definition Greatly accelerated extinction rate that results in a marked decrease in biodiversity, such as the mass extinction at the end of the Cretaceous period. Term Meiosis Definition Cell division that yeilds sex cells, sperm and eggs in animals and pollen and ovules in plants, in which the number of chromosomes is reduced by half. Term Mitosis Definition Cell division that results in two cells that have the same number of chromosomes as the parent cell; takes place in all cells except sex cells. Term Modern Synthesis Definition A combination of ideas of scientists regarding evolution that includes chromosome theory of inheritance, mutations as a source of variation, and gradualism,but rejects the idea of inhertance of acquired characteristics. Term Mosiac evolution Definition the concept that not all parts of an organism evolve at the same rate, thus yeilding organisms with features retained from the acestral condition Term Mutation Definition A change in the genes of organisms; yeilds some of the variation on which natural selection acts. Term Natural Selection Definition A mechanism that accounts for differential survival and reproduction among members of a species; the Mechanism proposed by Darwin and Wallace to account for evolution Term paleontology Definition The use of fossils to study life history and relationships among organisms. Term Parallel EvOlution Definition The development of similar features in tow or more closely related but seperate lines of descent as a consequence of similar adaptations. Term Phyletic gradualism Definition The concept that a species evolves gradually and continuously as it gives rise to new species. Term Punctuated equilibrium Definition A concept holding that a new species evolves rapidly, in perhaps a few thousand years, and then remains much the same during its several million years of existence. Term Species Definition A population of similar individuals that in nature can interbreed adn produce fertile offspring. Term Theory of EvoLUTion Definition The theory holding that all oraganisms are related and that they descended with modification from organisms that lived during the past. Term Trace Fossil Definition Any indication of prehistoric organic activity such as tracks, trails, and nests preserved in rocks. Term Vestigial structure Definition Structure in an organism that no longer serves any or only a limited function, such as dewclaws in dogs and wisdom teeth in humans.