Biology Ch. 18: Classification

Estimated 5 – 30 million species of organisms live on earth!!! Even with large catalogs and databases of known organisms, there are still places on earth where little is known about the diversity of life. 15% of species in rain forests are unidentified!!!

What is classification? the grouping of objects or information based on similarities. Why is it necessary to classify things? Give examples of classification you see in everyday life.

What is taxonomy? The branch of biology dealing with identifying and classifying organisms based on similar characteristics, chemical makeup and evolutionary history. The term taxonomy comes from the Latin word taxon (pl. taxa), which means “group.” Taxonomists place organisms into groups and give them scientific names.

Aristotle (384 – 322BC) Greek philosopher Developed the first classification system Two groups: plants vs. animals herbs shrubs trees land air water whales, fish & ducks all in same group???

Carolus Linnaeus Linnaeus (1707-1778) a Swedish botanist/naturalist known as the Father of Modern Taxonomy. He designed a system to name and classify organisms based on similarities in body structures and physical forms. Modern classification evolutionary relationships

Carolus Linnaeus His system was based on five different taxa. His taxa were organized from the broadest to the most specific. Modern taxonomy uses 7 taxa, including Linnaeus’ original five.

Binomial Nomenclature Binomial nomenclature (two names): group of closely realted species. Genus Species (scientific name) ex: human beings: Homo ( genus) sapiens (species)

Who uses taxonomy??? Scientists in agriculture, forestry and medicine

The 7 Levels of Classification K angaroos Kingdom P lay Phylum (pl. phyla) C ards Class O n Order F ine Family G reen Genus (pl. genera) S and Species

The 7 Levels of Classification Each taxa is more specific than the previous one. For example, kingdom is the largest, broadest taxon. A kingdom contains several phyla. A phylum contains several classes, and so on, down to species, the smallest, most specific taxon. A kingdom may include millions of organisms. A species includes only one.

An example of classification Classification of the Grizzly Bear (Ursus arctos)

Scientific Naming of Organisms What do you call this organism? Since one organism can have several names, scientists need a system that uses a single name for a single organism.

Scientific Naming of Organisms Linnaeus developed a naming system using Latin names for organisms. His system is known as binomial nomenclature, which means “two-name naming.” Each organism is given a name that includes two words.

Scientific Naming of Organisms The first name is the organism’s genus. The second name is the organism’s species. The genus is always capitalized; the species is always lowercase. The entire name is either printed in italics or underlined.

Scientific Naming of Organisms Ex. What is the scientific name of this organism? Its genus is Homo. Its species is sapiens. Its scientific name is Homo sapiens.

Scientific Naming of Organisms In longer names, the genus name can be abbreviated to a single capital letter. For example, this organism is known as Carcharadon carcharias. This can be shortened to C. carcharias.

Scientific Naming of Organisms So, what do you call this organism? Puma concolor!

The Six Kingdoms Eubacteria Unicellular, prokaryotic organisms. Eubacteria have thick cell walls. They can be autotrophs or hertertrophs. Ex. Cyanobacteria, E. coli

SIX KINGDOMS

The Six Kingdoms Archaebacteria Unicellular, prokaryotic organisms. They can be autotrophs or hertertrophs. They live in very harsh, extreme conditions, like volcanoes or other places without oxygen. Ex. Methanogens, thermophiles

The Six Kingdoms Protista Most are unicellular, eukaryotic organisms. Protists can be autotrophs or hertertrophs. Some plant-like; some animal-like; some fungus-like Live in moist environments Ex. amoeba, algae, paramecium

The Six Kingdoms Fungi Most are Multicellular, eukaryotic organisms. Fungi are heterotrophic decomposers. Absorbs nutrients obtained by decomposing dead organisms and wastes Ex. mushrooms, mold, yeast, penicillin

The Six Kingdoms Plantae Multicellular, eukaryotic organisms. Plant cells have cell walls containing cellulose. Plants are autotrophic. Photosynthesize. Tissues organized into organs and organ systems. Instead of phyla, plants are classified into divisions. Ex. moss, ferns, trees, gymnosperms, angiosperms

The Six Kingdoms Animalia Multicellular, eukaryotic organisms. Animal cells do not have cell walls. Animals are heterotrophic. Animalia is the largest of the six kingdoms. Tissues organized into organs and complex organ systems. Ex. insects, fish, YOU