1. CLASSIFICATION Ch. 17

2. What is Taxonomy?

3. Taxonomy
The science of classifying living things.

4. What are 2 reasons we classify?

5. To make things easier to find.
To show how things are alike.
To be able to accurately name organisms.

6. What are 2 problems associated with classification?

7. 2 Problems There are many different life forms.
People disagree on how to classify.

8. Early Classification Systems

9. Who was the first person to classify organisms?

10. ARISTOTLE
Divided organisms into 2 groups:
Plants and animals

11. Aristotle further divided plants into groups based on size.
Herbs Shrubs Trees
(short) (medium) (tall)

12. Aristotle divided animals into groups based on habitat.
air land water

13. What scientist developed the classification system we use today?

14. Carolus Linnaeus Swedish botanist.
Classified organisms based on their physical and structural similarities.
Two kingdoms- plant and animal.
7 taxons or levels of organization.
Developed binomial nomenclature

15. What are the classification groups (used today) in order from largest to smallest

16. Classification Hierarchy
Domain—largest group (recently established)
Kingdom
Phylum (“Division” used for plants)
Class
Order
Family
Genus
Species—smallest group (exceptions)

17. King
Phillip
Came
Over
For
Good
Spaghetti

19. The Linnaean classification system has limitations.
Linnaeus taxonomy doesn’t account for molecular evidence.
The technology didn’t exist during Linneaus’ time.
Linnaean system based only on physical similarities.

20. Physical similarities are not always the result of close relationships.
Genetic similarities more accurately show evolutionary relationships.

21. How are organisms given names?

22. Binomial Nomenclature
Two-part naming system devised by Linnaeus (still used today)

24. What are the rules for naming organisms?

25. Rules for Naming Organisms
1st word is the genus and is always capitalized.
2nd word is the species and is never capitalized.
Latin is always used.
Name is always written in in italics.

26. Binomial Nomenclature

27. Why is it important to use scientific names?

28. Why use Scientific Names?
Latin is a universal language.
They seldom change/less confusion.
Show relationship of a species.

30. MODERN TAXONOMY RULES Evolutionary relationship among organisms
Chromosome structure/karyotype
Reproductive potential
Biochemical makeup
Embryological development

31. Classification is always a work in progress.
The tree of life shows our most current understanding.
New discoveries can lead to changes in classification.
Until 1866: only two kingdoms, Animalia and Plantae
Animalia
Protista
Fungi
Plantae
1866: all single-celled organisms moved to kingdom Protista
Archea
Bacteria
1938: prokaryotes moved to kingdom Monera
1959: fungi moved to own kingdom
1977: kingdom Monera split into kingdoms Bacteria and Archaea

32. 3-DOMAIN SYSTEM (used today)
Domain Archaea—ancient bacteria; live in extreme environments
(Kingdom Archaea)
Domain Bacteria—most common bacteria
(Kingdom Bacteria)
Domain Eukarya—eukaryotic organisms
4 kingdoms

34. E. coli

35. What are the 4 kingdoms in the Domain Eukarya?

36. Kingdoms in Domain Eukarya
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia

39. Dichotomous Key A tool used to identify organisms
Characteristics given in pairs
Read both characteristics and either go to another set of characteristics OR identify the organism

40. Example of Dichotomous Key
1a Tentacles present – Go to 2
1b Tentacles absent – Go to 3
2a Less than 8 tentacles – Hydra
2b More than 8 tentacles–Go to 3
3a Tentacles hang down – go to 4
3b Tentacles upright–Sea Anemone
4a Balloon-shaped body–Jellyfish
4b Body NOT balloon-shaped - 5

41. KEY CONCEPT Modern classification is based on evolutionary relationships.
Pangolin

42. Cladistics is classification based on common ancestry.
Phylogeny is the evolutionary history for a group of species.
evidence from living species, fossil record, and molecular data
shown with branching tree diagrams

43. Cladistics is a common method to make evolutionary trees.
classification based on common ancestry
species placed in order that they descended from common ancestor
Armadillo
Glyptodon

44. A cladogram is an evolutionary tree that proposes how species may be related to each other through common ancestors.
A clade is a group of species that shares a common ancestor.
Each species in a clade shares some traits with the ancestor.
Each species in a clade has traits that have changed.

45. Derived characters are traits shared in different degrees by clade members.
FOUR LIMBS WITH DIGITS
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
EMBRYO PROTECTED BY AMNIOTIC FLUID
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW
FEATHERS & TOOTHLESS BEAKS.
SKULL OPENINGS BEHIND THE EYE
DERIVED CHARACTER
basis of arranging species in cladogram
more closely related species share more derived characters
represented on cladogram as hash marks

46. Nodes represent the most recent common ancestor of a clade.
FOUR LIMBS WITH DIGITS
Nodes represent the most recent common ancestor of a clade.
CLADE
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
FEATHERS AND TOOTHLESS BEAKS.
Clades can be identified by snipping a branch under a node.
SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
NODE
DERIVED CHARACTER

47. Molecular evidence reveals species’ relatedness.
Molecular data may confirm classification based on physical similarities.
Molecular data may lead scientists to propose a new classification.
DNA is usually given the last word by scientists!!!

48. Clades: Motorcycle Car Walking Bicycle airplane Derived Characters:
Wings
Wheels
Passengers enclosed
Clades:
Motorcycle
Car
Walking
Bicycle
airplane