1. History of Classification
Finding Order in Diversity

2. History of Classification
For more than 3.5 billion years, life on Earth has been constantly changing.
Natural Selection has led to a staggering diversity of organisms.
Biologists have identified and named about 1.5 million species so far
Estimate that 2 and 100 million have not yet been discovered.

3. Classification Why classify?
By using a scientific name, biologists can be certain that everyone is discussing the same animal.
Taxonomy
A discipline of classifying organisms and assigning each organism a universally accepted name.

4. History of Classification
How are living things organized for study?
a. When you hear the word “bird”, what mental picture appears?
A flying animal that has feathers

5. History of Classification
In a good system of classification, organisms placed into a particular group are more similar to each other than they are to other organisms in different group.
EX: We use a classification system. When you refer to “teachers”, or more specifically “zoology teachers”.

6. History of Classification
By the 18th century, European scientists realized that referring to organisms by common names was confusing. Common names vary among languages.
For example a cougar can also be called a puma, a panther or a mountain lion.
Southern california are called mountain lions. Florida calls them panthers.

7. History of Classification
In England, the word buzzard refers to a hawk whereas in many parts of the US, buzzard refers to a vulture.

8. History of Classification
Aristotle’s System
The first attempt at standardizing scientific names basically described the physical characteristics of a species.
EX: scientific name of a particular tree might be “Oak with deeply divided leaves that have no hairs on their undersides and no teeth around their edges.”

9. History of Classification
Carolus Linnaeus
Swedish botanist who lived during the 18th century.
binomial nomenclature
Classification system in which each species is assigned a two-part scientific name.
Bi is latin for “two” and nomen is latin for “name”.

10. 1. Linnaeus’s System of Classification
Classification system with 7 levels
Each level called taxon (plural: taxa)
Why 7 levels?
Lots of organisms

11. Classification System
Kingdom
Phylum
Class
Order
Family
Genus
Species
Country
State
County
City
Neighborhood
Street
House #

12. Kingdom Largest taxonomic group, consisting of closely related phyla
Eukaryotes
2 original kingdoms
Animalia
Plantae

13. Phylum
Group of closely related organisms that share important characteristics
Ex: Chordata – Humans & Bears

14. Class & Order Class – group of similar orders Mammalia
Internal regulation of body temp. (warm-blooded)
Have body hair
Produce milk for young
Order – broad taxonomic category composed of similar families
Carnivora
Bears - Ursidae
Dogs – Canidae
Cats - felidae

15. Family Share many characteristics EX: Bears – Ursidae and Ailuropoda
Polar bears
Grizzly bears
Panda bear
Grouped in larger category, Ursidae (all bears)

16. Genus & Species
Genus
Group of closely related species, and the first part of the scientific name in binomial nomenclature.
Species
Group of organisms that can breed and produce offspring that are fertile.
Grizzly Bear
Ursus arctos
Giant Panda
Ailuropoda melanoleuca
Polar Bear
Ursus maritimus

17. Binomial Nomenclature
2-word naming system
Each species is assigned a 2 part name
Always written in italics or underlined
First word is always capitalized
Genus species
Two smallest categories, genus and species (one organism). Ursus are grouped in a larger category. EX: polar bear in this genus
Grizzly bear ~ Ursus arctos

18. Questions??? How are organisms classified?
Living things are classified according to shared characteristics and organized into 7 categories.
What is binomial nomenclature?
A two-word naming system
Explain the difference between Aristotle’s system and Linnaeus's system of classification?
Aristotle’s common name system which can differ due to in languages.
Linnaeus’s system of binomial nomenclature

19. Modern Evolutionary Classification
What characteristics do scientists use to classify organisms?

20. Modern Classification
Organisms choose with whom they will mate.
Group organisms according to biologically important characteristics.
Linnaeus’s system grouped animals according to visible similarities and differences.
Problems???

21. Modern Classification
How would you classify the crab, limpet, and barnacle?

22. Look more closely! Limpet and barnacle larvae are very different.
CRAB
Limpet and barnacle larvae are very different.
Barnacles have jointed limbs.
Limpets DON’T !
Barnacles have a segmented body
Barnacles have an exoskeleton that molts.

23. Look more closely! Crab and barnacle larvae are very similar
LIMPET
CRAB
BARNACLE
Crab and barnacle larvae are very similar
Barnacles have jointed limbs.
So do CRABS !
Barnacles have a segmented body
Barnacles have an exoskeleton that molts.
Barnacles and crabs share an evolutionary ancestor that is more recent than the ancestor that barnacles share with limpets.

24. Modern Classification
Limpet’s are mollusks and have a foot like clams and limpet’s shell is one structure whereas barnacles’ shell have interlocking plates.

25. Modern Classification
Evolutionary Classification
Darwin’s ideas about descent with modification gave rise to the study of phylogeny.
The study of evolutionary relationships among organisms.
Evolutionary relationship of the Phylum Chordata

26. Modern Classification
Evolutionary classification
Method of grouping organisms together according to their evolutionary history.
All members of a genus share a recent common ancestor.

27. Modern Classification
Cladogram
Diagram that shows the evolutionary relationships among a group of organisms.
Derived character
Characteristic that appears in recent parts of a lineage, but not in its older members.
Derived
Characters

28. Modern Classification
Similarities in DNA and RNA
Genes of many organisms show important similarities.
DNA can be used to determine classification and evolutionary relationships.
They urinate on their legs which cools and removes body heat and storkes behavior the same way.
Are these organisms related?

29. Traditionally these first two were
Similarities in DNA can be used to help show evolutionary relationships and how species have changed.
African vulture American vulture Stork
Traditionally these first two were
classified together in falcon family.
Storks were put in a separate family.

30. The only other bird that does this is the STORK.
American vultures have a peculiar behavior. When they get overheated, they urinate on their legs to cool off
African vulture American vulture Stork
The only other bird that does this is the STORK.

31. DNA comparisons showed more similarities between American vulture and stork DNA than DNA from the two kinds of vultures suggesting a more recent common ancestor between storks and American vultures.
African vulture American vulture Stork

32. Questions???
What characteristics do scientists use to classify organisms.
Biological:
Structure (including similarities in DNA)
Physiological
behavioral
Evolutionary relationships; phylogeny
How are evolutionary relationships important in classification?
Accurate placement of organisms within their phylogenic tree.

33. What are the three-domain systems of classification?
Domains and Kingdoms
What are the three-domain systems of classification?
Bacteria
Archae
Eukaryota

34. 3 Domain System
Modern organisms have been grouped according to how evolved
Domain
More inclusive category; larger than a kingdom.
3 Domains:
Bacteria – unicellular & prokaryotic
Archaea - extremophiles
Eukarya – unicellular & multicellular Eukaryotes

35. 3 Domain System Eubacteria
Domain of unicellular prokaryotes that have cell walls containing peptidoglycans

36. 3 Domain System
Archaea
Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan
They live in extreme environments.
Colonies of haloarchaea on agar plates

37. 3 Domain System
Eukarya
Domain of all organisms whose cells have nuclei, including protists, plants, fungi and animals.

38. Tree of Life

39. 6 Kingdoms of Life The six-kingdom system of classification includes:
Eubacteria
Archaebacteria
Protista
Fungi
Plantae
Animalia

40. Domain Eukarya

41. Kingdom Protista
The kingdom Protista is composed of eukaryotic organisms that cannot be classified as animals, plants or fungi,
They can be unicellular or multicellular; photosynthetic or heterotrophic; and can share characteristics with plants, fungi or animals.

42. Kingdom Fungi
Kingdom composed of heterotrophs; many obtain energy and nutrients from dead organic matter (decomposers).
They can be either multicellular (mushrooms) or unicellular (yeasts).

43. Kingdom Plantae
Members of the Kingdom Plantae are multicellular, photosynthetic autotrophs that have cell walls containing cellulose.
Plants are nonmotile – they cannot move from place to place.

44. Kingdom Animalia
Members of the Kingdom Animalia are multicellular eukaryotic heterotrophs whose cells do not have cell walls.
There is great diversity within the animal kingdom, and many species exist in nearly every part of the world.

46. Questions??? What are the three-domain systems of classification?
Bacteria, Archae and Eukarya
What are the six kingdoms of life?
Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia