1. UNIT IV DIVERSITY OF LIVING THINGS Scientific Classification

2. Why Do We Classify Organisms?
CLASSIFICATION
the grouping of organisms by similarities
Biological classifications are based on how organisms are related.
Group A
Group B
Why Do We Classify Organisms?
Biologists group organisms to represent similarities and proposed relationships.
Classification systems change with expanding knowledge about new and well-known organisms.

3. Classification Binomial Nomenclature Hierarchical Classification
Two part name (Genus, species)
Hierarchical Classification
Seven Taxonomic Catagroies
Systematics
Study of the evolution of biological diversity
Taxonomy: the branch of biology concerned with the grouping and naming of organisms; the study of classification

4. Taxonomy
Organisms are classified into a hierarchy of groups and subgroups based on similarities that reflect their relationships over a period of time.

5. Cladogram or Phylogenic Tree
A branching, treelike diagram in which the endpoints of the branches represent specific species of organisms.
It is used to illustrate phylogenetic relationships and show points at which various species have diverged from common ancestral forms.
Animation - Phylogenetic Trees

6. Taxonomic Diagrams Phylogenetic Tree Cladogram Taxonomic Diagrams
Mammals
Turtles
Lizards and Snakes
Crocodiles
Birds
Mammals
Turtles
Lizards and Snakes
Crocodiles
Birds
Phylogenetic Tree
Cladogram
Taxonomic Diagrams
Sometimes, biologists group organisms into categories that represent common ancestries, not just physical similarities. Early naturalists used physical characteristics and later, fossil data, attempting to represent evolutionary relationships among organisms. Today, modern classification systems use fossil data, physical characteristics and DNA/RNA information to draw increasingly more accurate branching diagrams.
Phylogenetic trees, or phylogenies, represent hypothesized evolutionary relationships among organisms and may include extinct as well as modern species. Cladograms are based only on characteristics observable in existing species. The branching patterns in a cladogram are defined by the presence of unique, evolving innovations (derived characteristics) shared by all members of the group.
References
Campbell, N. E. & Reece, J. B. (2002). Biology (6th ed.). Benjamin Cummings.
Judd, W. S., Campbell, C. S., Kellogg, E. S., Stevens, P. F., & Monoghue, M. J. (2002). Plant Systematics: A Phylogenetic Approach, (2nd ed.). Sinauer Associates, Inc.
Image References
Dykinga J. Buffalo. USDA Agricultural Research Service.
Bauer, S. Turkey. USDA Agricultural Research Service.
Alligator, unknown
NOVA Development Corp. (1995) Insects & Reptiles #0517. Art Explosion, Volume 2 Clip Art
NOVA Development Corp. (1995) Insects & Reptiles #0557. Art Explosion, Volume 2 Clip Art

7. Tree of life
Biology: Samples -           

8. Aristotle’s Groups HISTORY:
Aristotle- developed the 1st method of classification
He divided all living things into 2 major groups
Aristotle’s Groups
He divided all living things into 2 major groups
1. Plants
classified by size and structure
2. Animals
classified by habitat (where they lived)

9. HISTORY: Aristotle Problems with his system:
Frogs live in both water and on land
Bats, birds and flying insects were grouped together

10. Kingdom Phylum Class Order Family Genus Kingdom – largest group
Phylum (sing.)
Phyla (pl.)(Plants don’t have phyla, they have divisions.)
Class
Order
Family
Genus
Species
Phylum
Class
Order
Family
Genus
These two taxa make up the scientific name.
Species

11. K__________ p__________ c_________
o___________ f________ g_________ s________.
King Phillip came over for great soup.

12. HISTORY:
Carolus Linnaeus- developed the modern system of classification
Father of Taxonomy

13. Binomial Nomenclature
Carolus von Linnaeus
Two-word naming system
Genus
Noun, Capitalized, Underlined or Italicized
Species
Descriptive, Lower Case, Underlined or Italicized

14. Binomial Nomenclature
Binomial nomenclature is a standard way of identifying a species with a scientific two-word name.
The first word is the genus name and the second the species name.
Scientific name - 2 Latin names
- Genus and species
- Capitalize the first letter of the genus
- Do NOT capitalize the species
- ALWAYS underline or use italics
Ex. Homo sapiens

15. Binomial Nomenclature
Scientific Name: Homo sapiens
Common Name:
Albert Einstein

16. Binomial Nomenclature
Scientific Name: Rudbeckia hirta
Common Name: Gloriosa daisy
or Black-eyed Susan

17. Binomial Nomenclature
Scientific Name: Pinus virginianis
Common Name: Virginia Pine

18. Binomial Nomenclature
Scientific Name: Harmonia axyridis
Common Name: Asian Ladybug

19. Binomial Nomenclature
Scientific Name: Ophiophagus hannah
Common Name: King Cobra

20. MODERN CLASSIFICATION SYSTEM
Organisms are grouped together on the basis of:
Similarity in structure
Felis domesticus
Panthera leo
Felis rufus

21. Similarity in structure
Canis lupus

22. Similarity in structure
Canis latrans

23. Similarity in structure
Canis domesticus

24. Organisms are grouped together on the basis of:
Similarity in genetic makeup (biochemistry)
Similarities among organisms on the structural and metabolic levels are reflected in the large degree of similarity in proteins and nucleic acids of different organisms.
Diversity is the product of variations in these molecules.

25. Organisms are grouped together on the basis of:
Similarity of embryonic development

26. Evolution: Library: Common Past, Different Paths

27. Organisms are grouped together on the basis of:
Similarity in evolutionary history
Phylogeny: the evolutionary history of a species based on comparing relationships between species using the fossil record

28. Organisms are grouped together on the basis of:
Similarity in behavior

29. Systematics: Evolutionary Classification of Organisms
Systematics is the study of the evolution of biological diversity, and combines data from the following areas.
Fossil record
Comparative homologies
Cladistics
Comparative sequencing of DNA/RNA among organisms
Molecular clocks

30. Classification is based on close evolutionary relationships of organisms.
Organisms classified in the same taxa (pl.) (taxon, sing.) share a common ancestry. They have evolved from the same common ancestral organism.

31. Evolutionary Relationships
Classification is hierarchal
each successive level is smaller and more closely related than the one before it

32. Species
organisms that belong to the same species can mate AND produce FERTILE offspring.

33. + = Horses and donkeys can mate. They produce a mule.
Mules are INFERTILE + =

34. + = Lions and tigers can mate. They produce a liger.
Ligers are INFERTILE + =

35. Why use scientific names?
Common names do not indicate how organisms are related or classified.
Common names can be misleading.
(e.g., seahorse, weeping willow)
Organisms with more than one
common name leads to mass
confusion.

36. Why Latin?
Latin is no longer spoken, and therefore, does not change as spoken languages do.
So, scientific names remain the same forever.