1. Classification of Living Things

2. Taxonomy
Branch of biology that names and groups organisms according to their characteristics and evolutionary history.
Does it have Legs? Feathers? Scales?
What did it look like before? What can you
compare it to?

3. History
The first person to group or classify organisms was the Greek teacher & philosopher ARISTOTLE.
(300 B.C.)

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

5. Problems?
Not all organisms fit into Aristotle’s 2 groups (plants or animals)
Ex: What about?
Bacteria Fungi

6. Problems? 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!

7. Problems? 3. Common names vary from place to place.
Ex: puma, catamount, mountain lion, cougar are all names for same animal

8. Problems?
4. Same organisms have different names in different countries.
Chipmunk
Streifenhornchen (German)
Tamia (Italian)
Ardilla listada (Spanish)

9. Quercus foliis obtuse-sinuatis setaceo-mucronatis
SOLUTION?
Some early scientists devised scientific names using long descriptions in LATIN.
Example: Red Oak
Quercus foliis obtuse-sinuatis setaceo-mucronatis
“oak with leaves with deep blunt lobes bearing hair-like bristles”

10. Problems Names too hard and long to remember!
Names don’t show relationships between different animals!

11. Carolus Linnaeus To The Rescue!
Devised a new classification system based on MORPHOLOGY
(Organism’s form and structure)
( )

12. Linnaeus’s System
Grouped in a HIERARCHY of 7 different levels
Each organism has a two part LATIN SCIENTIFIC NAME

13. Kingdom
Phylum
Class
Order
Family
Genus
Species
Kids
Prefer
Cookies
Over
Fried
Green
Spinach

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

15. BINOMIAL NOMENCLATURE (2 name naming system)
1st name = GENUS NAME
Always capitalized
2nd name = SPECIES IDENTIFIER
Always lower case
Both names are UNDERLINED or written in ITALICS

16. Binomial Nomenclature
Vampire bat Desmodus rotundus
Eastern chipmunk
Tamias striatus

17. Binomial Nomenclature
Humans
Homo sapiens or

18. SPECIES
“Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups.”
Reproductively isolated group
Ernst Mayr

19. DIFFERENT SPECIES

20. Remember: Linnaeus only had 2, plant and animal
So What Do We Use Now?
MODERN TAXONOMY
Still use Linnaeus’s system: but we have added more KINGDOMS
Remember: Linnaeus only had 2, plant and animal

21. The Kingdoms
Archaebacteria
Eubacteria
Protist
Fungi
Plantae
Animalia

22. The Phyla We’re Studying
Porifera (sponges)
Cnidaria (jellyfish and corals)
Nemotode (roundworms)
Platyhelminthes (flatworms)
Molluska (clams, squid, octopi)
Annelids (earthworms)
Arthropods (crabs, insects, spiders)
Echinoderms (starfish, urchin)
Chordates (vertebrates)

24. MODERN TAXONOMY

25. Modern Taxonomy

26. MODERN TAXONOMY
Organizes living things in the context of evolution

27. MODERN TAXONOMY
Scientists use different kinds of info to classify organisms:
Fossil record
Morphology
Embryology
Chromosomes
Macromolecules (DNA & proteins)

28. FOSSIL RECORD
We can trace some changes over time through the fossil record.
Evolutionary history = PHYLOGENY

29. MORPHOLOGY
Shape and Function

30. MORPHOLOGY HOMOLOGOUS characteristics:
same embryological origin (may have similar structure and function)
EX: Bat wing & human arm
Homologous characteristics suggest a recent common ancestor

31. MORPHOLOGY ANALOGOUS characteristics:
may have similar structure & function but different embryological origin
EX: Bird wing & butterfly wing
ANALOGOUS characteristics evolved separately.
Organisms NOT CLOSELY RELATED

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

33. EMBRYOLOGY
Animals whose embryos develop in a similar pattern may be related

35. CHROMOSOMES
Similar karyotypes suggest closer relationships.

36. 46 individual
chromosomes
48 individual
chromosomes
4 individual
chromosomes

37. MACROMOLECULES Compare molecules like
PROTEINS (amino acids)
DNA
Organisms with similar sequences are probably more closely related.

39. Terminology Classification
Assigning organisms to different categories based on their relationship
Taxonomy
The science of naming organisms
Systematics
Determining evolutionary relationships of organisms
Phylogeny
Evolutionary history