1. Classification of Living Things

2. Classification of Living Things
Taxonomy: Branch of biology that names organisms according to their characteristics.
Putting things into orderly groups based on similar characteristics.
Why do scientists classify?
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 group or classify organisms
(300 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. Limitations of Early Classification
1. Not all organisms fit into Aristotle’s groups (plants or animals)
Ex: Bacteria Fungi
Images from:

6. 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:

7. 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:

8. Limitations of Early Classification
4. Same organisms have different names in different countries.
Chipmunk
Streifenhornchen (German)
Tamia (Italian)
Ardilla listada (Spanish)
Image from:

9. 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”

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

11. “Father” of taxonomy and binomial nomenclature
Carolus Linneaus
Devised a new classification system based on morphology
(Organism’s form and structure)
( )
“Father” of taxonomy and binomial nomenclature

12. Carolus Linnaeus Linnaeus’s Classification System
Organisms grouped in a hierarchy of seven different levels
Each organism has a two part scientific name
Binomial Nomenclature

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

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

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

18. Binomial Nomenclature
Vampire bat Desmodus rotundus
Image from:
Eastern chipmunk
Tamias striatus
Image from:

19. Binomial Nomenclature
Humans
Homo sapiens
Homo sapiens
Image from:

20. Modern Taxonomy
Modern taxonomy involves the use of Linnaeus’s naming/classification system, but with additional kingdoms.

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

22. Modern Taxonomy
Scientists use a variety of information in order to classify organisms:
Fossil Record
Morphology
Embryology
Chromosomes
Macromolecules (DNA and Proteins)

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

24. 2. MORPHOLOGY Shape and Function
Image from:

25. Homologous characteristics suggest a recent common ancestor
Morphology
Homologous Characteristics:
Same embryological origin (may have similar structure and function)
Example: Bat Wing and Human Arm
Homologous characteristics suggest a
recent common ancestor

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

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

28. 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!

29. I don’t get it!
Analogous characters  the same function but different underlying construction.
Homologous characters  different functions, but show an anatomical similarity inherited from a common ancestor. **Important for cladograms!**

30. 3. Embryology
Animals whose embryos develop in a similar pattern may be related
Image from:

31. Even differences show relatedness
amnion /am·ni·on/ (am´ne-on) bag of waters; the extraembryonic membrane of birds, reptiles, and mammals, which lines the chorion and contains the fetus and the amniotic fluid

32. 4. Chromosomes Similar karyotypes suggest closer relationships.
Human:
Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

33. Even differences show relatedness
Human- 46 chromosomes Chimpanzee- 48 chromosomes
Even differences show relatedness
Chimpanzees have 2 smaller chromosome pairs we don’t have
Humans have 1 larger chromosome pair (#2) they don’t have.
Human:
Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

34. 5. Macromolecules
Comparison of macromolecules such as Proteins and DNA
Organisms with similar sequences are (thought to be) more closely related.

35. Macromolecules

36. Evolutionary Relationships
Determined through the use of:
Morphology
Fossil Record
Embryology
Chromosomes
Macromolecules
Evolutionary relationships can be illustrated on a phylogenetic tree

37. Cladistics
Shows evolutionary relationships based on “shared derived characteristics”
Cladistic relationships illustrated through the use of a Cladogram
Phylogeny:
Evolutionary History

39. Cladogram
The greater the number of derived characters shared by groups, the more recently the groups share a common ancestor.

40. Domains Three Domains: 1. Archaea 2. Bacteria 3. Eukarya
Domains are taxonomic groups that are even bigger than kingdoms. Each of the six kingdoms belongs to a single domain.
Three Domains:
1. Archaea
2. Bacteria
3. Eukarya Do
Kids
Prefer
Cheese
Over
Fried
Green
Spinach?

41. Domain Bacteria
Eubacteria are prokaryotes whose cell walls contain peptidoglycan.
“True bacteria”

42. Domain Archaea
Archaea are thought to be more ancient than bacteria and yet more closely related to our eukaryote ancestors.
Cell walls without
peptidoglycan
They are called extremophiles because they can live in extreme environments.

43. Domain Eukarya All eukaryotes are classified in Domain Eukarya.
Domain Eukarya contains Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia.

44. Kingdom Archaebacteria
Some archaebacteria are heterotrophs, but some are autotrophs.
Most archaebacteria are unable to move, but a few can move.
Archaebacteria are the old known life forms.
Why are archaebacteria not classified with “modern bacteria”?
Archaebacteria and eubacteria are chemically different!

45. Kingdom Archaebacteria
Cool archaebacteria info:
Three divisions of archaebacteria: Methanogens: methane producing organisms
Thermophiles: These can live in extremely hot, acidic environments like sulfur springs.
Halophiles: Can only live in bodies of concentrated salt water, like the Dead Sea.

46. Kingdom Eubacteria Traditional prokaryotic bacteria Unicellular.
Some are autotrophic, some are heterotrophic.
Found in soil, water, human body, etc.
Esterichia coli (E. coli) is found in large numbers in human intestines, where it produces vitamin K.

47. Kingdom Eubacteria Unlike archaebacteria, eubacteria require oxygen.
Some bacteria contain cilia or flagella which allows them to move. 47

48. Kingdom Protista Eukaryotic organisms.
This is why they are not considered bacteria!
Most protists are single-celled but some are simple, multicellular organisms
“Junk Drawer Kingdom” or “Odds and Ends Kingdom”
Some protists are autotrophic, some protists are heterotrophic.
Animal-like protists, plant-like protists 48

49. Most protists are able to move, but some cannot
Kingdom Protista
Most protists are able to move, but some cannot

50. Kingdom Fungi Molds and mushrooms are examples of fungi.
Fungal cell walls contain chitin.
(cell walls of plants contain cellulose).
The study of fungi is known as mycology.
Fungi are more closely related to animals than to plants!
Usually, the only fungi that we see are reproductive structures. Tasty!!

51. Kingdom Plantae Plants are eukaryotic, multicellular organisms.
They are autotrophs- they make their food through photosynthesis.
Plants can be found on land and in shallow water (where there is light)

52. Kingdom Plantae Plant cells have cell walls
Made up of cellulose, to provide them with a rigid structure
Some plants reproduce through both asexual and sexual reproduction.

53. Kingdom Animalia
This kingdom contains many complex, multicellular organisms.
All animals are heterotrophic.
All animals are able to move, even if it is only during some stages of the life cycle.

54. Kingdom animalia
All animals are eukaryotic organisms, but animal cells do not have a cell wall.
Most animals reproduce through sexual reproduction, but some are able to reproduce asexually (or both!).
The most simple organism
in the kingdom animalia
is a sponge.