CLASSIFICATION OF LIVING THINGS CLASSIFICATION Biology Taxonomy Scientists
CLASSIFICATION OF LIVING THINGS
CLASSIFICATION Biology
Taxonomy Scientists classify organisms and assign each organism a universally accepted name
Why Should We Classify Organisms? To organize similar organisms So all scientists are discussing the same organisms (species) Species population of organisms that share similar characteristics and can breed with one another and produce fertile offspring Identified 1. 5 million species so far Estimate 2 -100 million have yet to be discovered
What tools can we use to show similarities in organisms? Cladistic analysis identifies and considers only those characteristics of organisms that are evolutionary innovations – new characteristics that arise as lineages evolve over time Cladogram – diagram that shows evolutionary relationships among a group of organisms
Modern Evolutionary Classification Darwin’s ideas about descent gave rise to the study of phylogeny – evolutionary relationships among organisms Evolutionary Classification – Grouping of organisms based on evolutionary history
Traditional Classification Versus Cladogram Appendages Crab Conical Shells Barnacle Limpet Crustaceans Crab Barnacle Gastropod Limpet Molted exoskeleton Segmentation CLASSIFICATION BASED ON VISIBLE SIMILARITIES Tiny free-swimming larva CLADOGRAM
Genes of many organisms show important similarities at a molecular level. Similarities in DNA can be used to help determine classification and evolutionary relationships
Carolus Linnaeus Swedish botanist that developed a two-word naming system called BINOMIAL NOMENCLATURE Gives the Genus and species name, written in italics or underlined Language is usually Latin Example: House cat – Felis domesticus Dog – Canis familaris Human – Homo sapien
Linnaeus’s System of Classification (8 Levels/ Taxa) Domain (most inclusive, less in common) Kingdom Phylum Class Order Family Genus Species (less inclusive, more in common) Each level is called a TAXON; taxa (plural)
Figure 18 -5 Classification of Ursus arctos Grizzly bear Black bear Giant panda Red fox Abert squirrel KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos Coral snake Sea star
Domains Currently, all organisms are grouped into 1 of 3 domains which reflect evolutionary relationships 1) Bacteria 2) Archaea 3) Eukarya ARCHAEA EUKARYA Kingdoms BACTERIA LUCA – last universal common ancestor Eubacteria Archaebacteria Protista Plantae Fungi Animalia
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