Classification Organizing Life

Scientists estimate that between 5 & 30 million species of organisms live on our planet, although fewer than 2 million have been identified and named. In order to simplify the study of these organisms, biologists have organized living things into related groups.

Some Key Vocabulary Classification  grouping of objects or information based on similarities Taxonomy  the branch of Biology concerned with the grouping and naming of organisms

WHY CLASSIFY? Taxonomists organize living things into groups using a set of characteristics or criteria that shows similarities or differences Logic Order Taxonomy is a useful tool Pine trees have a resin used as a disinfectant; other evergreens might also have useful substances. (Medicine) similar plants might contain similar chemical substances. It is used in agriculture, forestry, & medicine It is important to the economy

HOW DO WE CLASSIFY? Dichotomous key A set of paired statements that can be used to identify organisms Organisms can be identified and relationships can be determined by ancestors, development, biochemistry, or behavior.

And now….a history lesson…

Aristotle’s system He developed the first method of classification His system had two major groups of organisms – plants and animals He grouped things according to where they were commonly found. Ex: Bats & Birds are related because they both live in the air. Problems with Aristotle’s system Greek Philosopher (384BC – 322BC) Birds, bats, & flying insects would be grouped together even though they have little in common besides the ability to fly. Some animals live both on land and in the water. It did not show natural relationships among organisms

Linnaeus’ system Developed a system that’s still used today He grouped organisms based on shared physical characteristics. Example #1: Flowering plants were grouped according to the number and similarities of reproductive structures Example #2: Bats – fly, hair, feed milk to young Birds – fly (Bats are grouped with mammals not birds)

BINOMIAL NOMENCLATURE Linnaeus’ system He developed a two-word system called: BINOMIAL NOMENCLATURE Capitalized 1st word = genus name (group of closely related species) Lower case 2nd word = species name (description of organism) Examples Grizzly Bear  Ursus arctos Polar Bear  Ursus maritimus

Used to name the organism TAXONOMIC CATEGORIES Organisms are grouped into a series of categories called TAXA: DOMAIN – most inclusive, groupings of kingdoms KINGDOM – group of related phyla PHYLUM – group of related classes CLASS – group of related orders ORDER – group of related families FAMILY – group of closely related genera GENUS Used to name the organism } SPECIES

TAXONOMIC CATEGORIES Grizzly bear Black bear Giant panda Red fox Abert squirrel Coral snake Sea star KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos

THE THREE DOMAINS BACTERIA ARCHAEA EUKARYA Viruses are left our of the kingdoms because they cannot live on their own, they are not considered cells and thus are not considered to be living.

THE SIX KINGDOMS EUBACTERIA ARCHAEBACTERIA PROTISTS FUNGI PLANTS Viruses are left our of the kingdoms because they cannot live on their own, they are not considered cells and thus are not considered to be living. ANIMALS

CONCEPT MAP FOR LIVING THINGS are characterized by such as and differing which place them in which coincides with which is subdivided into Living Things Kingdom Eubacteria Kingdom Archaebacteria Eukaryotic cells Prokaryotic cells Important characteristics Cell wall structures Domain Eukarya Domain Bacteria Domain Archaea Kingdom Plantae Kingdom Protista Kingdom Fungi Kingdom Animalia

Describe Modern Evolutionary classification This classification system grouped organisms based on their phylogeny not just physical similarities. Phylogeny – evolutionary history of a species.

Evolutionary histories are based on the following: Structural Similarities Breeding Behavior Geographical Distribution Chromosome Comparisons Biochemistry

Structural Similarities Shared physical structures -different types of cats -dandelion, sunflower

Breeding Behavior How animals attract the opposite sex. -frogs croak…birds chirp…baboons have colorful backsides

Geographical Distribution Location of species

Chromosome comparisons Chromosomes nearly identical in structure -cauliflower, cabbage, kale -Chimpanzees, humans, gorillas

Biochemistry Similar DNA sequences Red panda and raccoons Giant pandas and bears

Quiz Why was the use of Linnaeus’s system better than Aristotle’s system? Define phylogeny. Name the taxonomic rankings in order from smallest to largest. Name two things that are considered when using Evolutionary classification. Which system is used to name organisms?