1. Classification and Taxonomy
Ch. 26 sect. 2-3

2. 1. Classification
the grouping of objects or organisms based on a set of criteria
scientist use classification to sort and group all the organisms on Earth

4. 1. Classification I. Taxonomy
the science of classifying living organisms
Goal: to give organisms identity and discover relationships between organisms

6. 1. Classification II. Developers of classification A. Aristotle
Greek philosopher
officially categorized organisms for the first time

7. 1. Classification Aristotle’s System of Classification Plants herbs
bushes
trees
Animals
land
air
water
l a n d
a i r
w a t e

8. 1. Classification Limitations of Aristotle’s system:
based on the belief that species do not change
no place for extinct species
difficult to categorize
some species as land or water

9. 1. Classification B. Polynomial nomenclature
Romans named organisms using Latin terms
Used long descriptive names to identify organism
ex. Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis, utrinque margine ciliates
European Honeybee

10. 1. Classification C. Carolus Linnaeus 1700’s Swedish Biologist
Developed classification system based on morphology
Morphology: structure or form of an organism
Developed binomial nomenclature
Apis mellifera European honeybee

11. 1. Classification II. Binomial Nomenclature two part naming system
uses Genus and species
Genus name is always capitalized
Species name is never capitalized
Name is italicized or underlined when written
To abbreviate
first letter of the Genus (H.) and the full species name (sapien).

12. 2. Levels of Classification
Domain
very broad group above kingdom
3: Bacteria, Archaea, Eukarya
Kingdom
broad group that is classified based on a similar feature
6: Animalia, Plantae, Fungi, Protista, Archaea, and Bacteria

13. 2. Levels of Classification
Phylum
group of classes with similar features
Class
group of orders with common features
Order
group of similar families

14. 2. Levels of Classification
Family
group of genera with similar features
Genus
group of similar species
Species
group of similar animals that can interbreed and produce viable offspring

15. 3. How to identify groups
Organisms can be identified using a dichotomous key
a set of criteria used to identify features and identify a named organism

16. 3. How to read a dichotomous key

17. Classification Levels Flip-chart
Create a saying using the first letter of each level
Write it on a flip chart
top side saying
underside actual name and description of level

18. Bellwork: Compare these two birds. Are they the same species?
How can you tell?

19. 4. Taxonomy I. 1700-Present species are grouped based on
shared physical characteristics (morphology)
ability to interbreed

20. Inadequacies of Linnaean System
not useful for making evolutionary predictions
only looks at morphology
separate species can look alike, act alike, and interbreed

21. Inadequacies of Linnaean System
artificially makes groups
3 of the 6 kingdoms are not monophyletic
Protista, Archaea, and Bacteria
monophyletic = having a single common ancestor

22. 2. Taxonomy II. Modern Taxonomy Phylogenetic approach
distinguishes relationships based on evolutionary history
creates phylogenies to identify and name a new species

23. 2. Taxonomy III. Phylogeny based on molecular data (ex. DNA)
identifies groups more effectively
group = a common ancestor and its descendents
identifies when a species diverged from the common ancestor

25. 2. Taxonomy Goals of Phylogeny to identify major clades
clade = a monophyletic group
to predict past evolutionary change
to identify relationships between species

26. 3. How to Read a Phylogenetic Tree
Each branch represents a different group
each split represents a molecular change
the point of separation is the most recent common ancestor