Classification

Sorting it all outSorting it all out

Why Classify?

• Classification is putting things into orderly groups based on similar characteristics.

• Allows us to figure how many species there are in the world

• Tells us the defining characteristics of each species

• Shows us the relationship between species

• Think of a classification system you may use in your everyday life. Why do you use this system?

Taxonomy

• Taxonomy: the science of describing, naming, and classifying organisms

• In the 1700’s Carolus Linnaeus discovered the seven level system of classification that we still use today

These levels of classification incorporate all of the living organisms of the world. Even though we are constantly discovering new organisms and new species, we are able to fit these new species into Linnaeus’ levels of classification.

Seven Levels of Classification

DomainKingdom

PhylumClassOrderFamily

Genus

Species

Domains• A three-domain system is used to classify living

organisms. Organisms are placed into domains and kingdoms based on their cell type, their ability to make food, and the number of cells in their body.

1.Bacteria (Eubacteria): unicellular prokaryotes (cells lack a nuclueus),

• Some are autotrophs while others are heterotrophs • Some are harmful (ex. Strep throat) and some helpful (ex.

yogurt)• Very common• Kingdom of Eubacteria

Domains cont…2. Archaea: unicellular prokaryotes

• Archaea is Greek for “ancient”, these organisms are the oldest known organisms on Earth

• Some are autotrophs while others are heterotrophs• Can be found in deep ocean with hot gasses and

molten rock, salty water, swamps, and even intestines of a cow!

• These harsh living conditions are related back to the ancient world

• Different chemical make-up than bacteria• Not as common as bacteria• Kingdom of Archaeabacteria

Domains cont…

3. Eukara: eukaryotes (cells contain nuclei)• Organisms in this domain can be classified into 4

kingdoms– Protists

– Fungi

– Plants

– Animals

Kingdoms

• Largest level of classification

• Contains similar phyla

• There are 6 different kingdoms

1.Archaebacteria

2.Eubacteria

3.Protista

4.Fungi

5.Plantae

6.Animalia

Kingdom History

Levels of classification

Animal

Kingdom

Phylum

Chordata

Class

Mammalia

Order

Carnivora

Family

Felidae

Genus

Felis

Species

Felis domesticus

All animals are in the kingdom Animalia.

All animals in the phyllum Chordata have a hollow nerve cord. Most have a backbone.

Animals in the class Mammalia have a backbone. They also nurse their young.

Animals in the order Carnivora have a backbone, nurse their young, and have special teeth for tearing meat.

Animals in the family Felidae are cats. They have a backbone, nurse their young, have special teeth for tearing meat, and have retractable claws.

Animals in the genus Felis have traits of other animals in the same family. However, these cats cannot roar- they can only purr.

The species Felis domesticus is the common house cat. The house cat shares traits with all of the organisms in the levels above the species level, but also has unique traits.

Which kingdom?

• Organisms are divided into kingdoms based on….

1. Cell Type – Prokaryote (no nuclei) or Eukaryote (nuclei)

Which Kingdom cont…2. Cell Number- unicellular or multicellular

3. Feeding Type- autotroph or heterotroph

Key Characteristics of Domains & Kingdoms

Bacteria

Fungi

Kingdom Cell Type Cell # Feeding Type

Cell Wall

Fact or Example

Archaebacteria

Eubacteria

Protista

Fungi

Plantae

Animalia

Archaebacteria• Ancient bacteria• Live in harsh/extreme environments• Prokaryote• Unicellular• Autotrophs and heterotrophs• Cell wall is present- contains no

peptidoglycan (polymer)

Eubacteria.. Or just plain bacteria

• When people talk about bacteria, this is the type they usually mean

• Live in more neutral conditions• Prokaryote• Unicellular• Some autotrophs and some heterotrophs• Cell Wall present

Nitrifying bacteria (autotroph)

E.Coli, helps break down food in your intestines (heterotroph)

Protists• All eukaryotes that are not plants, animal, or

fungi• Unicellular and simple multicellular organisms • There are animal-like protists called

protozoans (no cell wall), that are heterotrophs

• There are plant-like protists like algae (cell wall present), that are autotrophs

• Slime molds, water molds• Odds and ends group

Fungi• Molds and mushrooms• Unlike plants, fungi Do NOT perform

photosynthesis• Unlike animals, fungi do NOT eat food• Heterotrophs, absorb nutrients from substances

in their suroundings• Reproduce using spores• Eukaryotic cells• Multicellular

• Cell wall present

Plants• Eukaryotic cells, multicellular• Cell wall present• Create own food through photosynthesis, making

plants autotrophs• Plants provide nutrients and habitat for other

organisms

Animals• Complex, multicellular organisms • Eukaryotic• No cell wall present• Usually able to move around, and have specialized

sense organs• Usually have quick response to environment• Animals depend on plants and other animals for food,

making animals heterotrophs• Animals depend on bacteria/fungi to recycle nutrients

found in dead organisms• Simple organisms like worms, insects, corals, and

sponges are also animals

Phylum Examples in Animal Kingdom

• Chordata- dorsal nervous chord (spinal column)

• Mollusca- muscular foot, shell

• Cnidaria- Have cnidae (stinging cells), have a nerve net but no true nervous system, no head, 2 way gut

• Annelida- segmented, bilaterally symmetrical, closed circulatory system, setae

There are 35 different phyla in the Animal Kingdom alone!

Classification of Man

• Kingdom Animalia• Phylum Chordata• Class Mammalia• Order Primates• Family Hominidae• Genus Homo• Species sapien

Binomial Nomenclatureaka

Scientific Name• Binomial = TWO terms• Nomenclature = given NAME

• Linnaeus discovered a scientifically useful way to name organisms no matter how many common names there may be– Ex.) In North and South American, a certain large cat is called a

mountain lion by some people, a cougar by others, and a puma still by others. However, its scientific name is always the same, Felis concolor

– Genus + species = scientific name

– Scientific names are written in italics, the Genus always capitalized and the species lowercase.

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