BIOLOGICAL DIVERSITY CHAPTER 26 THE TREE OF LIFE text first two sections pg 508 514 26 1 Origins of Life All organisms share fundamental properties of life cellular organization o all organisms consist of one or more cells o all organisms respond to sensitivity sensitivity growth development reproduction regulation homeostasis environment heredity o living things can assimilate energy and use it to maintain internal order and grow metabolism o unicellular and multicellular undergo gene directed change as they mature and grow o all living things reproduce and pass on genetic info o living things have regulatory systems used to coordinate internal processes o living things maintain constant internal conditions that are different from their o all living things have a genetic system that is based on the replication of DNA allows for evolution all living things evolve 26 2 Classification of Organisms Taxonomy is a quest for identity and relationships Aristotle named things as either plants or animals Greeks and Romans grouped animals and plants into units like cat horses and oaks in the Middle Ages names were systematically written in Latin Linnaeus instituted the use of binomial names Carolus Linnaeus 1707 1778 used polynomial names for some organisms but also used two part short hand names called binomials taxonomy science of classifying living things o no two organisms can have the same scientific name o names are the same throughout the world o names are written as Genus capitalized species not capitalized and is written in italics ex Homo sapiens Taxonomic hierarchies have limitations The Linnaean hierarchy o organisms are grouped into larger and more inclusive categories genera with similar characters families with similar characters common orders family order class phylum kingdom domain classes with similar characters phyla is assigned to one very generalized group archaea bacteria protista fungi plantae animalia three levels and is the eighth level of classification Limitations of the hierarchy groups o many higher taxonomic ranks are not monophyletic and therefore do not present natural common ancestor and all of its descendants is a natural group that results from descent from a common ancestor any other type of group paraphyletic or polyphyletic is an artificial grou o Linnaean ranks are not equivalent in any meaningful way comparisons btw Linnaean categories may be incorrect
View Full Document
Unlocking...