Evolution Latest Update Graded A+

Evolution Latest Update Graded A+ adaptation any trait or behavior that increases an organisms likelihood of survival natural selection the natural process whereby those varieties in a population that are better adapted for the environment are more likely to survive nature's forces than those varieties that are not well suited for the environment microevolution a small change within a population macroevolution a large scale change in a population that results in the creation of a new species mutation any change in the DNA sequence; produces new adaptations in a population disruptive selection a type of natural selection where the extreme phenotypes have the best adaptations to survive and make up the majority of future populations fitness measured by the ability of an organism to reproduce fertile offspring directional selection a type of natural selection where one extreme phenotype has the best adaptation to survive and makes up the majority of future populations stabilizing selection a type of natural selection where the intermediate phenotypes have the best adaptations to survive and make up the majority of future populations founder effect a type of genetic drift whereby members of a population leave and create a much smaller population (Amish) gene pool the genes available for intermixing in a population when reproduction happens bottleneck effect a type of genetic drift where organisms are randomly killed off by events such as a natural disaster rather than those less well adapted ones dying off in a population gene flow the transfer of genes from one population to another when organisms migrate into a new population evidence of evolution: comparative embryology comparing the similarities in embryonic development in organisms with the idea that the more similar development occurs between two species the more closely related they are evidence of evolution: biogeography the study of how living things are distributed on the earth evidence of evolution: biochemistry using similarities in DNA Sequences and amino chains that make up proteins to show close evolutionary relationship * the more DNA that two organisms share or the more similar two amino acid sequences are = the more closely related they are in evolutionary history evidence of evolution: comparative anatomy comparing similarities in body structure to show evolutionary relationship evidence of evolution: comparative physiology comparing similarities in the function of cells, tissues, organs, organ systems, etc to show evolutionary relationship phylogenetic tree a branching tree showing the inferred evolutionary relationships between species cladogram a diagram showing the relationship of organisms based on the existence of certain derived characters or adaptations evidence of evolution: fossil record using the remains of living organisms to document evolutionary relationship fossils can include preserved: 1. bone 2. organism in tar or sap 3. footprints 4. nests or egg shells 5. droppings speciation process of creating a new species species Members of a population that are morphologically similar and can reproduce to make fertile offspring. geographic isolation (allopatric speciation) isolation of a population based on a physical barrier where two different populations occupy different habitats and therefore will not cross paths to mate reproductive isolation (sympatric speciation) isolation of a population that prevents mating success where certain behaviors (mating call, coloration, dance, etc) is what attracts one member of the species to another to encourage mating events or where two populations mate at different times homologous structure a structure that several species share because they all share a common ancestor; evidence of divergent evolution analogous structure a structure that exists in two populations not because they are closely related but rather because they live in similar environments with similar environmental pressures vestigial structure a structure that no longer serves a function necessary for survival; an evolutionist would argue that it is left over from our evolutionary past - that the common ancestor of the species needed that structure for survival sexual selection A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. Migration A movement from one population to another; this process causes gene flow Coevolution Process by which two species evolve in response to changes in each other divergent evolution when two or more species sharing a common ancestor become more different over time convergent evolution Process by which unrelated organisms independently evolve similarities when adapting to similar environments