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BIOL 1001
Tamara Kelly

Mosaic evolution is the concept that evolutionary change takes place in some body parts or systems without simultaneous changes in other parts An ancestral character is a character inherited from a common ancestor A derived character is a trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants Systematists look at characters that are genetically independent because these are the true indicators of speciation and differentiation They cannot rely on phenotypic traits because similarities in a species physical appearance may arise from convergent evolution Homologous traits are characteristics that are similar in two species because they inherited the genetic basis of the trait from their common ancestor HomoplasiousAnalogous traits are characteristics shared by a set of species often because they live in similar environments but not present in their common ancestor often the product of convergent evolution If a characteristic between two species is considered homologous the common ancestor must have the trait as well and we would expect its descendants to have the trait too If a characteristic between two species is considered analogous the common ancestor did not have the trait and the similarity arose from convergent evolution Derived characters provide the most useful information about evolutionary relationships because once a derived character becomes established it is usually present in all of that species descendants Similar characters found between species are usually evidence that the common ancestor had this trait as well so they are ancestral characters Outgroup comparison is a technique used to identify ancestral and derived characters by comparing the group under study with more distantly related species that are not otherwise included in the analysis If the two species have the same characteristic that is under study then that character is an ancestral one Cladistics is an approach to systematics that uses shared derived characters to infer the phylogenetic relationships and evolutionary history of groups of organisms Cladistics produces phylogenetic hypotheses and classifications that reflect only the branching pattern of evolution Cladistics ignores morphological divergence SpeciesClassifying Distribution Issues with Defining What a Species isDefinitionsKnowledge QuestionsDefinitionsBiosphereall regions of Earths crust waters and atsomphere that sustain lifeEcosystemGroup of communities interacting with their shared physical environmentCommunityPopulations of all species that occupy the same areaPopulationGroup of individuals of the same kind that is the same species that occupy the same areaMulticellular Organismorganisms that consists of more than one cellAbioticnonliving chemical and physical factors in the environmentradation temperature water atmosphere and soilBioticLiving things that shape an ecosystempredation competition parasitism mutualism and commensalismSpecies RichnessBiodiversityDefine three different types of biodiversity species communityecological genetic
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