This document provides information about taxonomy and biological classification. It discusses why biologists classify organisms and defines taxonomy as the branch of biology that groups and names organisms based on their characteristics. It describes how Carolus Linnaeus developed the binomial nomenclature system for scientific naming of organisms. This system uses the genus and specific epithet to uniquely identify each species. The document outlines the taxonomic hierarchy from kingdom down to species and explains how living things are classified into a logical categorization system based on their evolutionary relationships.

1. Taxonomy and
Classification

2. Why Classify
• Biologists want to better understand
organisms so they organize them.
• One tool that they use to do this is
classification—the grouping of objects or
information based on similarities.
• Taxonomy is the branch of biology that groups
and names organisms based on studies of their
different characteristics.
• Biologists who study taxonomy are called
taxonomists.

3. Keeping track of species
• >1 million species named, up to 15 million more.
• Taxonomy is not new; cultures have been
naming plants and animals around them for
1000’s of years.
• It’s practical to have names.
• The Greek philosopher Aristotle (384-322 B.C.)
developed the first widely accepted system of
biological classification.
• He classified all the organisms he knew into two
groups: plants and animals.

4. Which one is easier?
“Watch out—there’s a bear behind that rock!
OR
“Watch out--there is a large, furry, four-legged
creature with long claws, a big mouth set
in a short, stout muzzle, attached to a
round head containing small eyes and
short triangular ears behind that rock!”

5. Q. What is the largest wild felid (cat)
in the United States?
Mountain Lion
Cougar
Panther
Painter
Puma
Catamount

6. All of the above
Puma concolor

7. Who devised a system
for classification?
• Carolus Linneaus (1707 -1778)
a swedish naturalist.
• Devised a two part naming
system known as binomial
nomenclature.

8. Binomial Nomenclature
• Standard two-part system for naming things.
• In this system, the first word identifies the
genus of the organism.
• A genus (genera-plural) consists of a group of
similar species.
• The second word, which sometimes describes
a characteristic of the organism, is called the
specific epithet.
Linnaeus described and named > 6,000 animals
and >4,000 plants using Latin
Scientific name does not replace, but instead
further defines common name

9. • Scientific names should be italicized in print
and underlined when handwritten.
• Taxonomists are required to use Latin
because the language is no longer used in
conversation and, therefore, does not change.
• The first letter of the genus name is
uppercase, but the first letter of the specific
epithet is lowercase.
Passer domesticus
Scientific and common names

10. • Even though the genus and species
are thorough sometimes more is
needed.
• Varities are splits of species. Example
peaches & nectarines are both from a
peach tree.
• Subspecies are variations of species
that occur in different regions.

11. May tell you where it was first discovered:
– Didelphis virginiana “2 wombs from Virginia”
– Sylvilagus floridanus “wood-hare of Florida”
Or who discovered it:
– Lepus townsendii “hare” discovered by
“Townsend”

12. • Grouping organisms on the basis of their
evolutionary relationships makes it easier to
understand biological diversity.
Modern Classification
• Expanding on Linnaeus’s work, today’s
taxonomists try to identify the underlying
evolutionary relationships of organisms and
use the information gathered as a basis for
classification.
• Taxonomists group similar organisms, both
living and extinct. Classification provides a
framework in which to study the relationships
among living and extinct species.

13. How Living Things Are Classified
• In any classification system, items are
categorized, making them easier to find and
discuss.
• Although biologists group organisms, they
subdivide the groups on the basis of more
specific criteria.
• A group of organisms is called a taxon (plural,
taxa).
• Organisms are ranked in taxa that range from
having very broad characteristics to very specific
ones.
• The broader a taxon, the more general its
characteristics, and the more species it contains.

14. Taxonomic Hierarchy
Mnemonic
Kingdom kings
Phylum play
Class cards
Order on
Family fine
Genus green
Specific epithet (species) sofas

15. Taxonomic rankings
• The smallest taxon is species. Organisms
that look alike and successfully interbreed
belong to the same species.
• The next largest taxon is a genus—a group of
similar species that have similar features and
are closely related.

16. • Compare the appearance of a lynx, Lynx rufus,
a bobcat, Lynx canadensis, and a mountain
lion, Panthera concolor.
Lynx Mountain
lion
Bobcat
Taxonomic rankings

17. Taxonomic goals
Place organisms into logical categories
– system must be capable of being used for
information retrieval, so anyone can
properly identify any organism
Place organisms into categories that
show ancestor-descendant
relationships

18. Taxonomic hierarchy
Kingdom (Animalia)
Phylum (Chordata)
Class (Mammalia)
Order (Carnivora)
Family (Canidae)
Genus (Canis)
Specific epithet (species) (familiaris)
Scientific name: Canis familiaris

19. THIS IS NOT MY DOG!!!!

20. • The evolutionary history of a species is called its
phylogeny.
Phylogenetic Classification: Models
• A classification system that shows the
evolutionary history of species is a phylogenetic
classification and reveals the evolutionary
relationships of species.
• One biological system of classification that is
based on phylogeny is cladistics.
• Scientists who use cladistics assume that as
groups of organisms diverge and evolve
from a common ancestral group, they retain
some unique inherited characteristics that
taxonomists call derived traits.

21. Six Kingdom
System

22. Kingdom Archaebacteria
• Unicellular, Prokaryote
• Either autotroph or
heterotroph
• Cell walls made of
peptidoglycan
• Reproduces by binary
fission
• Lives in Harsh
environments: salty lakes,
hot springs, anaerobic
environments
• AKA–Kingdom Moneran

23. Kingdom Eubacteria
• Unicellular, prokaryote
• Either autotroph or
heterotroph
• Cell walls made of
peptidoglycan
• Reproduces by binary
fission
• Includes common bacteria:
tooth decay, yogurt
production, food poisoning
• AKA–Kingdom Moneran

24. Kingdom Protista
• Unicellular or multicellular
• Eukaryotic
• Cell walls made of varying
materials
• Autotroph or heterotroph
• About 50,000 species
• Reproduces-asexually
• Examples include:
– Euglena
– Amoeba

25. Kingdom Fungi
• Unicellular or multicellular
• Eukaryotic
• Heterotrophic
• Cells walls made of chitin.
• Reproduces - asexually
• 100,000 species
• Including: toadstools,
mushrooms, puffballs,
rusts or smut

26. Kingdom Plantae
• Multicellular
• Eukaryotic
• Autotrophic
• Can reproduce both
ways.
• Cell walls made of
cellulose.
• All but a few are land
dwellers. 350,000
species
• Including:mosses, ferns,
conifers, flower plants

27. Kingdom Animalia
• Multicellular
• Eukaryotic
• Heterotrophic
• No cell walls
• Reproduces
sexually by meiosis.
• All animals have
some type of
symmetry