ClassificationChapter 18

Dr. Donna HowellBiology – Blacksburg High School

Finding Order in Diversity

What is Classification?• Put simply,

the putting into groups and naming of organisms.

• We classify because it helps us see the relationships between different organisms.

Taxonomy• The

science of classifying and naming organisms is called taxonomy.

Binomial Nomenclature• Organisms are

classified by a system called binomial nomenclature.

• Bi means “two” and this means that each species is assigned a two-part scientific name.

Genus & Species• The first part

of the name is the genus.

• Example: all bears have the genus of Ursus.

• The second part of the name is the species. This is unique to each type of bear.

Carolus Linnaeus• Carolus Linnaeus

is the scientist that came up with the hierarchial system of classification that includes 7 levels:– Kingdom– Phylum– Class– Order– Family– Genus– Species

Carolus Linnaeus• The broadest

category is the kingdom.

• All animals are in the kingdom Animalia.

• Then gradually it gets more specific, eventually reaching the species level.

Modern Evolutionary Classification

Evolutionary Classification

• Phylogeny is the study of evolutionary relationships between organisms.

• Organisms are now grouped into lines of evolutionary descent.

Cladograms• One way

evolutionary relationships are shown is through a cladogram.

• Each branch on a cladogram represents a new adaptation in the family line.

Similarities in DNA and RNA

• Another way we can show evolutionary relationships is through analyzing DNA and RNA.

• This is much more accurate than other methods.

Kingdoms and Domains

The Six Kingdoms• The current

classification system contains six kingdoms:– Eubacteria– Archaebacteri

a– Protists– Fungi– Plantae– Animalia

The Three Domains• Most

scientists now use a 3 domain classification system:– Archaea– Bacteria– Eukarya

• Plants• Animals• Fungi

Protists

Domain Archaea• Archaea are

the most primitive bacteria.

• They are unique in that they live in extreme environments, such as high salt, high heat, cold, acid, etc.

Domain Bacteria• The bacteria

are unicellular organisms that are prokaryotes (cells don’t have nuclei)

• Live EVERYWHERE!

• Cause disease

Domain Eukarya - Protista

• The protists are unicellular and multicellular organisms with many different characteristics.

• Ex: malaria, algae, and many pond water organisms.

Domain Eukarya -Fungi• The fungi are

organisms that feed on dead and decaying matter.

• Ex: mushrooms, yeast, molds, athlete’s foot, etc.

Domain Eukarya -Plantae• The plants are

organisms that undergo photosynthesis.

• Ex: trees, flowers, grasses, etc.

Domain Eukarya -Animalia

• The animals are organisms that are more advanced than other organisms.

• Ex: mammals, rodents, fish, reptiles, amphibians, birds, etc.

The End!