1. Classification of Living Things
Prof.Tamboli A.Z. Dept of zoology, S.M. Joshi College, Hadapsar. F.Y.B.Sc.

2. Classification of Living Things
Taxonomy: science of classification
Branch of biology that names organisms according to their characteristics, and places them into orderly groups based on similar characteristics.
Why ?
Biologists classify living organisms to answer questions such as:
How many known species are there?
What are the defining characteristics of each species?
What are the relationships between these species?

3. Aristotle
Aristotle
Greek philosopher and teacher more than 2000 years ago
The first person to devise a classification system-according to natural environment
(350 B.C.)

4. Aristotle PLANTS: Based on size of stem Based on where they lived
ANIMALS:
Based on size of stem
Based on where they lived

5. John Ray 17th Century Classified according to characteristics
Why are there problems with this???

6. Limitations of Early Classification
1. Not all organisms fit into Aristotle’s groups (plants or animals)
Ex: Bacteria Fungi
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7. Limitations of Early Classification
2. Common names can be misleading
Ex: A jelly fish isn’t a fish,
but a seahorse is!
Sea cucumber sounds like a plant but… it’s an animal!
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8. Limitations of Early Classification
3. Common names vary from place to place
Ex: puma, catamount, mountain lion, cougar are all names for same animal
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9. Limitations of Early Classification
4. Same organisms have different names in different countries.
Chipmunk
Streifenhornchen (German)
Tamia (Italian)
Ardilla listada (Spanish)
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10. Limitations of Early Classification
Early Solution:
Description of Organism Using Latin Names
RED OAK
Quercus foliis obtuse-sinuatis setaceo-mucronatis
“oak with leaves with deep blunt lobes bearing hairlike bristles”

11. Limitations of Early Classification
Problem with Latin Name descriptions?
Names too long and difficult to remember
Names don’t illustrate evolutionary relationships

12. “Father” of taxonomy and binomial nomenclature
Carolus Linneaus
Devised a new classification system based on morphology
(Organism’s form and structure)
Formed a species
Similar species group together to form a genus
( )
“Father” of taxonomy and binomial nomenclature

13. Use of genus and species names to form scientific name
This system is called binomial nomenclature
Binomial means two parts
Nomenclature means system of naming
Latin is used-dead language

14. Binomial Nomenclature
Binomial Nomenclature: Two name naming system
Italicized or Underlined
1st Name = Genus
Capitalized
2nd Name = Species Identifier
Lower case

15. Binomial Nomenclature
Vampire bat Desmodus rotundus
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Eastern chipmunk
Tamias striatus
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16. Binomial Nomenclature
Humans
Homo sapiens
Homo sapiens
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17. Robert Whittaker-1969 5 kingdom system of naming
Animalia, Plantae, Protista, Monera, Fungi
Levels of classification from broadest to narrowest
KPCOFGS

18. Kingdom Phylum Class Order Family Genus Species Kings Play Cards On
Fat
Green
Stools

19. Kingdom Phylum Class Order Family Genus Species Animalia Chordata
Mammalia
Carnivora
Felidae
Panthera
leo

22. Modern Taxonomy
Modern taxonomy involves early naming/classification system, but with additional kingdom.
Domain is the most general grouping

23. Organizes living things in the context of evolution
Modern Taxonomy
Organizes living things in the context of evolution

24. Modern Taxonomy
Scientists use a variety of information in order to classify organisms:
Chromosome Structure
Reproductive Potential
Biochemical Makeup/Protein Comparison
Morphology- Homologous Structures

25. 2. Reproductive potential
If two organisms can interbreed AND produce fertile offspring they are considered of the same species

26. 3. Biochemical makeup Comparison of macromolecules such as Proteins
Similar amino acid sequences in proteins indicate similar organisms

27. Macromolecules

28. 4. MORPHOLOGY Shape and Function
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29. Morphology Homologous Structures:
Embryological source of similar structures indicate a possible common ancestor
Example: Bat Wing and Human Arm
P. 262

30. develop from same embryonic structures
Morphology
Bat wing
and human arm
develop from same embryonic structures
HOMOLOGOUS
STRUCTURES

31. Morphology Analogous Characteristics:
May have similar function, but different embryological origin
Example: Bird Wing and Butterfly Wing
Analogous characteristics evolved separately.
Organisms not necessarily closely related.

32. have evolved with similar function
ANALOGOUS STRUCTURES
Bird wing and
butterfly wing
have evolved with similar function
BUT
different structure
inside.
Insects and birds NOT closely related!