Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Species distribution wikipedia , lookup
Designer baby wikipedia , lookup
Human genetic variation wikipedia , lookup
Group selection wikipedia , lookup
Genetic drift wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Hybrid (biology) wikipedia , lookup
Population genetics wikipedia , lookup
Big Idea 1: Evolution Vocabulary adaptation a heritable trait that enhances an individual’s fitness adaptive radiation The emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems. allele alternative versions of a gene that produce distinguishable phenotypic effects. allopatric speciation A mode of speciation induced when an ancestral population becomes segregated by a geographic barrier or is itself divided into two or more geographically isolated subpopulations. analogous structure similar structures that evolved separately in different lineages antibiotic resistance the ability of a microorganism to resist the effects of an antibiotic to which they were once sensitive artificial selection the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits. bottleneck effect Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population. cladogram diagram depicting patterns of shared characteristics among species clades a group of species that includes an ancestral species and all its descendants common ancestor an organism that is an ancestor of two different organisms that are not related to each other convergent evolution process whereby organisms, not closely related, independently evolve similar traits as a result of adapting to similar environment’s directional selection Natural selection that favors individuals at one end of the phenotypic range. disruptive selection Natural selection that favors individuals on both extremes of a phenotypic range over intermediate phenotypes. divergent evolution process by which interbreeding populations or species diverges into two or more descendent species, resulting in becoming more dissimilar emigration movement of individuals out of a population evolution All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today fertility ability to produce offspring founder effect Genetic drift that occurs when a few individuals become isolated from a larger population, with the result that the new population's gene pool is not reflective of the original population. gene flow Genetic additions to or subtractions from a population resulting from the movement of fertile individuals or gametes. gene pool The total aggregate of genes in a population at any one time. genetic drift Unpredictable fluctuations in allele frequencies from one generation to the next because of a population's finite size. homologous structures structures in different species that are similar because of common ancestry hybrid an offspring that was given different genetic information for a trait from each parent immigration the influx of new individuals from other areas isolation types six different mechanisms that prevent the sperm and egg from coming together limited resources a resource which cannot be made available on a scale which can sustain its composition rate mutation A rare change in the DNA of a gene ultimately creating genetic diversity. natural selection Differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool. outgroup A species or group of species that is closely related to the group of species being studied, but clearly not as closely related as any study-group members are to each other. phenotype the physical and physiological traits of an organism, which are determined by its genetic makeup phylogenetic tree A branching diagram that represents a hypothesis about evolutionary relationships. population A localized group of individuals that belong to the same biological species (that are capable of interbreeding and producing fertile offspring). protobiont An aggregate of abiotically produced molecules surrounded by a membrane or membrane-like structure random mating the choice of mates in which chance plays the biggest part reproductive isolation the existence of biological factors (barriers) that impede members of two species from producing viable, fertile hybrids serial endosymbiosis A model of the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had been engulfed by larger cells. sexual selection natural selection for mating success speciation origin of new species in evolution species A group whose members possess similar anatomical characteristics and have the ability to interbreed. stabilizing selection natural selection that favors intermediate variants by acting against extreme phenotypes sterility incapable of producing offspring sympatric speciation a mode of speciation occurring as a result of a radical change in the genome of a subpopulation, reproductively isolating the subpopulation from the parent population variation differences between members of the same species vestigial organs Structures of marginal, if any, importance to an organism. They are historical remnants of structures that had important functions in ancestors. viability capable of living