1. Taxonomy “The Study of Classification”

2. What do you think? What does classification mean?
Why is classification important?
When do we use classification systems in our everyday lives?
Books at the library, iPods and movies, even people!

3. Objectives Learn about the history of classification systems
Recognize Linnaeus’ contribution
Discuss classification keys and their usefulness
Study Phylogenic trees and Cladograms
Outline the 6 Kingdom system

4. What exactly is classification?
Classification is a branch of Biology called Taxonomy.
Taxonomy classifies based on similarities
…but it wasn’t always this way!

5. Meet Aristotle (350 BC)
Aristotle classified all living organisms as either a plant or an animal.
He further classified animals by where they lived, and plants by their size.

6. Aristotle’s Classification Scheme
ALL LIVING ORGANISMS
PLANTS
ANIMALS

7. PLANTS
SHORT (Herbs) MEDIUM (Shrubs) TALL (Trees)

8. ANIMALS
LAND WATER AIR

9. What are some problems with this classification system?
Some animals live in more than one habitat during their lives.
Most plants start small and grow larger.

10. These problems were recognized by Carolus Linnaeus
“The Father of Modern Taxonomy”

11. Carolus Linnaeus
Linnaeus was a Swedish botanist who lived in the 18th century.
He decided to classify organisms based on their visible similarities and differences in structure.

12. Carolus Linnaeus
Linnaeus made three huge contributions to modern taxonomy:
Using structural criteria for classification
Establishing the 7 taxa currently used.
Created the Binomial Nomenclature

13. The 7 Taxa Kingdom Phylum Class Order Family Genus Species
Pneumonic Device:
King
Phillip
Came
Over
For
Ginger
Snaps
Kingdom
Phylum
Class
Order
Family
Genus
Species
Used in Scientific Names

14. 7 Taxa
Kingdom
Phylum
Class
Order
Family
Genus
Species

15. Did you notice?
As you go down through the 7 taxa, you get more and more details about the organism you are looking at.
Organisms get more and more similar from top to bottom.

16. Let’s Classify Us! Let’s classify a human: Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: Sapiens

17. Binomial Nomenclature
Binomial nomenclature is a “two word” naming system.
The first term describes the organisms genus while the second term describes the species.

18. Genus and Species
Organisms placed in the same genus have similar structures (look the same).
Organisms with the same species name are so similar they would be able to reproduce under normal circumstances to produce fertile offspring.

19. Binomial Nomenclature
Scientific names are written in Latin and have something to do with the organisms characteristics or where they live. (Castor canadensis) (Ursus horribilus)
Scientific names are written in italics or underlined.
The first term is always capitalized while the second isn’t
Example: Homo sapiens  humans
Homo sapiens
H. sapiens

20. Examples of Scientific Names
Canis lupus  Wolf
Canis familiaris  Dog
These organisms are structurally similar (same genus) but different species (cannot reproduce under normal circumstances to produce fertile offspring)

21. Scientific Names Equus caballus - horse Equus asinus – donkey
When a donkey and a horse reproduce, their offspring is a mule, which is sterile. (1 in will have an offspring)

22. Check out the Scientific Names

23. KEY TERMS
SYSTEMATICS
Scientific study of the diversity of organisms and their natural (evolutionary) relationships
A systematist seeks to reconstruct phylogeny

24. KEY TERMS PHYLOGENY MONOPHYLETIC
Evolutionary history of a species or other taxonomic group
MONOPHYLETIC
Said of a group consisting of organisms that evolved from a common ancestor

25. KEY TERMS
CLADISTICS
Classification of organisms based on recency of common ancestry rather than degree of structural similarity

26. Cladistics
Cladists emphasize phylogeny by focusing on when evolutionary lineages (lines of descent) divide into two branches
Cladists develop cladograms

27. KEY TERMS
CLADOGRAM
A diagram that illustrates evolutionary relationships based on the principles of cladistics

28. Building a Cladogram

29. Characters TAXON VASCULAR TISSUES SEEDS FLOWERS Moss A A A Fern P A A
Pine P P A
Figure 18.7: Building a cladogram.
Refer to the table as you follow the process in (a) through (c). (Adapted from Dr. John Beneski, Department of Biology, West Chester University, West Chester, Pennsylvania)
Daisy P P P

30. (a) All of the plant groups shown here except mosses have vascular
Pine
Moss
Daisy
Fern
Common ancestor
with vascular tissues
Figure 18.7: Building a cladogram.
Refer to the table as you follow the process in (a) through (c). (Adapted from Dr. John Beneski, Department of Biology, West Chester University, West Chester, Pennsylvania)
Node 1
Common plant
ancestor
(a) All of the plant groups shown here except mosses
have vascular

31. (b) Seeds are a shared character for all plant groups
Pine
Moss
Daisy
Fern
Node 2
Common ancestor
with vascular tissues
Figure 18.7: Building a cladogram.
Refer to the table as you follow the process in (a) through (c). (Adapted from Dr. John Beneski, Department of Biology, West Chester University, West Chester, Pennsylvania)
Node 1
Common plant
ancestor
(b) Seeds are a shared character for all plant groups
shown here except mosses and ferns.

32. (c) Of the plant groups shown here, only the daisy produces flowers.
Pine
Moss
Daisy
Fern
Node 3
Common
seed-
producing
ancestor
Node 2
Common ancestor
with vascular tissues
Figure 18.7: Building a cladogram.
Refer to the table as you follow the process in (a) through (c). (Adapted from Dr. John Beneski, Department of Biology, West Chester University, West Chester, Pennsylvania)
Node 1
Common plant
ancestor
(c) Of the plant groups shown here, only the daisy
produces flowers.