Classification of Living Things Mod B U 1

Classification of Living Things Mod. B U. 1 L. 5 1

Why Do We Classify? Allows us (scientists) to keep track of the 3 to 10 million different living things on Earth! Organized, Easier to study 2

Classification: Is the systematic grouping of organisms into categories on the basis of evolutionary (or genetic) relationships or physical appearance shared traits 3

The Science of classifying is called “Taxonomy” People have been classifying for nearly 2, 000 years! 4

Classification - Scientific Naming □Carolus Linnaeus • The “Father of Taxonomy” • Developed systems for naming species and organizing them into groups • Named over 4000 plants & animals • Used appearance to group species • Used binomial nomenclature 5

What is Binomial Nomenclature? • “Bi-nomial” = “two” - name • “Nomenclature” = a naming system • Language: Latin 6

• Example: Common house cat –Felis domesticus Mountain lion, puma, cougar – Felis concolor Bobcat – Felis rufus Genus species Always capitalized, / always lower-case Both are always italicized in print • Genus and species are the most specific levels of organization 7

Eight Levels of Classification The modern classification system uses several levels to classify organisms. The more characteristics that organisms have in common, the more levels they share. 8

OLD System 1. Kingdom 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Species NEW System 1. 2. 3. 4. 5. 6. 7. 8. Domain Kingdom Phylum Class Order Family Genus Species 9

There are 8 levels of classification that describe a species DOMAIN • Kingdom • Phylum • Class • Order • Family • Genus • Species Eukarya Animalia Chordata Mammalia Carnivora Ursidae Ursus maritimus Eukarya Animalia Chordata Mammalia Primate Hominidae Homo sapiens Animalia Chordata Mammalia Carnivora Canidae Canis familiaris The more levels of organization that two organisms share, the more closely related the two organisms are! 10

There are 3 Domains: 1. Archaea – Prokaryotes(single celled, no nucleus) Live in extreme environments 2. Bacteria - Prokaryotes Cell walls, Binary fission 3. Eukarya Multicellular, Eukaryotes(cells nucleus and membrane-bound 11

6 Kingdoms of Organisms Bacteria (Monera) Archeabacteria Protists Fungi Plants Animals 12

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Branching Diagrams Branching diagrams show the close evolutionary relationships between organisms. As characteristics differ, branches in the diagram 16

Cladograms Common ancestor 17

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Phylogentic (Evolutionary) Tree 19

Dichotomous Keys Taxonomist have developed special guides know as dichotomous keys to aid in identifying unknown organisms. n A dichotomous key consists of several pairs of descriptive statements that have only two responses. n Narrow down your choices till specimen is identified n 20

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