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

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?

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.)

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

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

Limitations of Early Classification 1. Not all organisms fit into Aristotle’s 2 groups (plants or animals) Ex: Bacteria Fungi Images from: http://www.leighday.co.uk/upload/public/docImages/6/Listeria%20bacteria.jpg http://danny.oz.au/travel/iceland/p/3571-fungi.jpg

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! Image from: http://www.alaska.net/~scubaguy/images/seacucumber.jpg

Limitations of Early Classification 3. Common names vary from place to place Ex: puma, catamount, mountain lion, cougar are all names for same animal Image from: http://www4.d25.k12.id.us/ihil/images/Cougar.jpg

Limitations of Early Classification 4. Same organisms have different names in different countries. Chipmunk Streifenhornchen (German) Tamia (Italian) Ardilla listada (Spanish) Image from: http://www.entm.purdue.edu/wildlife/chipmunk_pictures.htm

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”

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

“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 (1707-1778) “Father” of taxonomy and binomial nomenclature

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

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

Binomial Nomenclature Vampire bat Desmodus rotundus Image from: http://212.84.179.117/i/Vampire%20Bat.jpg Eastern chipmunk Tamias striatus Image from: http://www.entm.purdue.edu/wildlife/chipmunk_pictures.htm

Binomial Nomenclature Humans Homo sapiens Homo sapiens Image from: http://www.earlylearning.ubc.ca/images/photo_baby.jpg

Robert Whittaker-1969 5 kingdom system of naming Animalia, Plantae, Protista, Monera, Fungi Levels of classification from broadest to narrowest KPCOFGS

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

Kingdom Phylum Class Order Family Genus Species Animalia Chordata Mammalia Carnivora Felidae Panthera leo http://www.vetmed.wisc.edu/dms/fapm/personnel/tom_b/2004-lion.jpg

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

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

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

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

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

Macromolecules

4. MORPHOLOGY Shape and Function   Image from: http://www.angelfire.com/ab7/evolution12/evolutionclues.html

Morphology Homologous Structures: Embryological source of similar structures indicate a possible common ancestor Example: Bat Wing and Human Arm P. 262

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

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.

have evolved with similar function ANALOGOUS STRUCTURES Bird wing and butterfly wing have evolved with similar function BUT different structure inside. http://uk.dk.com/static/cs/uk/11/clipart/bird/image_bird003.html Insects and birds NOT closely related! http://www.naturenorth.com/butterfly/images/05a%20tiger%20wing.jpg