Classification of Living Things

Chapter 7

Why There is a Need for Classifying

• There are well over 2 million different types of organisms known.

Why There is a Need for Classifying

• Biologists place the organisms into groups based on their characteristics.

• By classifying, biologists can organize living things into groups.

Taxonomy

• The branch of Biology that deals with the naming and placing of all organisms into groups.

Early Classification Schemes

• The earliest attempt at classifying organisms placed all organisms into one of two groups.

E arly C lass ifica tion

P lan ts A n im a ls

L ivin g Th in g s

Classification by Aristotle and Theophrastus

• Aristotle classified animals according to where in the environment they lived.

• Theophratus classified plants according to their stem structure

A ris to tle 's C lass ifica tion

A ir D w e lle rs L an d D w e lle rs W ater D w e lle rs

A n im a ls

Th eop h ras tu s 's C lass ifica tion

H erb s(so ft s tem )

S h ru b s(S evera l w od d y s tem s)

Trees(s in g le w ood y s tem )

P lan ts

• The early Classification schemes were based mainly on structural similarities.

Today’s Classification Schemes

• The basis for modern Taxonomy centers around evolutionary relationships

Today’s Classification Schemes

• Today Taxonomists use a variety of information to classify or group organisms.

• Structural

• Biochemical

• Cytological Information

• Embryological Information

• Behavioral

The 5 Kingdom System Of Classification

• All Living things on earth can be placed in one of 5 groups known as Kingdoms

5 Kingdom Classification

5 K in g d om s

A n im a ls P lan ts F u n g i M on era P ro tis ta

L ivin g Th in g s

Kingdom Monera

• Unicellular

• Prokaryotic

• may be photosynthetic, chemosynthetic, or feed by absorption.

Bactreia are common monerans

Kingdom Protista

• Most are unicellular

• Eukaryotic

• may be photosynthetic, may feed by absorption, or may ingest food.

Protists

Kingdom Fungi

• Most multicellular although some are unicellular.

• Eukaryotic cell structure

• Absorptive Heterotrophs

• Non Motile

Fungi

Kindom Plantae

• Multicellular

• Eukaryotic

• Photosynthetic

• Non Motile

Plants

Kingdom Animalia

• Multicellular

• Eukaryotic

• Ingestive Heterotrophs

• Motile

• Nervous system present

Animals

Classification Categories

• Within any Kingdom there are many levels of classification.

• Kingdom• Phylum• Class• Order• Family• Genus• Species

• Within any kingdom there are many phylum

• Within any phylum there are several classes

• Within any Class there are several Orders

• Within any order there are several Families

• Within any Family there are several Genus

• Within a Genus there may be many species

• Every Organism on earth is placed into each of the classification categories

Humans

• Kingdom Animalia

• Phylum Chordata

• Class Mammalia

• Order Primates

• Family Hominidae

• Genus Homo

• Species Sapien

Domestic Dog

• Kingdom Animalia

• Phylum Chordata

• Class Mammalia

• Order Carnivora

• Family Canidae

• Genus Canis

• Species familaris

Naming Organisms

• In addition to classifying organisms, taxonomists also name each type of living organism.

• Naming is also called Nomenclature

Binomial Nomenclature

• “Two names”

• Taxonomists name organisms by stating the organisms genus followed by a given species name.

Examples

• Homo sapiens - Humans

• Canis familaris - dog

The use of Latin in naming

• As you have noticed latin is used for naming.

• Latin at one time was the language of scholars

Common Names

• In addition to scientific names organisms may also be given common names.

Common names can cause confusion

• StarFish - not a fish

• What we may know as the green pepper is also referred to as a bell pepper, or sweet pepper.

• Common names also vary from language to language

• Dog - perro - inu .

Benefit of Universal Naming

• A universal system of naming allows us to avoid the confusion associated with common names, and tells us something about evolutionary relationships.