1. Classifying Organisms
Chapter 3 Section 1

2. Why do Scientists Classify?
Imagine a grocery store…
How are they organized?
What would happen if they were not organized?
How is your life organized?

3. Why do Scientists Classify?
Almost 2 million kinds of organisms on Earth
Need to keep organized! (Easier to study!)
Classification
= process of grouping things based on their similarities

4. Why do Scientists Classify?
Taxonomy
=scientific study of how living things are classified
Useful because:
once classified, scientists will know a lot about an organism

5. Early Classification Systems
Aristotle (4th century B.C.)
-observed animals
-watched appearance, behavior, movement
-fly, swim, and walk/crawl/run
-observed similarities and differences
-used differences to divide into smaller subgroups

6. The science of classifying organisms is called taxonomy
The “father of modern taxonomy” was Carolus Linnaeus (Carl von Linné)
Organisms are grouped into “taxa” based on their similarities to each other

7. Linnaeus Carolus Linnaeus (1750s)
-used observations as basis of his system
-placed organisms based on observable features
Devised naming system for organisms:
Binomial Nomenclature

8. Linnaeus Binomial Nomenclature =2 part naming system -uses Latin words
Genus species Felis concolor
Genus is capitalized; species is NOT.
If you can’t italicize, underline the genus and species!

9. Classification Today
Species with similar evolutionary histories are classified more closely together.
-when organisms share a common ancestor, they share an evolutionary history

10. 6 Kingdoms Archebacteria Eubacteria 6 Kingdom Classification System
Kingdom Eubacteria: true bacteria
(formerly in kingdom monera)
Kingdom Archebacteria: extremophiles (formerly in kingdom monera)
Kingdom Protista (same)
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia

11. 3 Domain System:
Archaea: prokaryotes; extremophiles
Eubacteria: prokaryotes; true bacteria
Eukarya: eukaryotes
Protista
Fungi
Plantae
Animalia

12. Domain Archaea Formerly part of the kingdom monera
Microbiologists who study bacteria determined that the DNA of these are much different from other, true bacteria
Most Archaea live in extreme conditions (very hot, acidic/basic, sulfurous, etc)

13. Domain Eubacteria Formerly a part of the kingdom monera
Name means “true bacteria”
These are the kind of bacteria likely to make us sick, live in our gut to help us digest food, or be used in the making of cheese
Bacilli
Streptococcus
Staphylococcus
Dicoccus
Spirilla

14. Domain Eukarya
Contains all of the eukaryotes (organisms with a nucleus in their cells)
Protista
Fungi
Plantae
Animalia

15. Levels of Classification
-based on contributions of both Aristotle and Linnaeus
There are 8 levels of classification.
Remember the first letter of this sentence:
Dumb Kids Play Catch Over Farmer Green’s Shed.

16. 8 Levels of Classification
Domain broadest level
Kingdom
Phylum
Class
Order
Family
Genus
Species most specific

18. Kingdom Protista Animal-Like (Protozoans) Fungus-Like Plant-Like
Paramecium
Giardia
Amoeba
Fungus-Like
Includes All Protists:
Eukaryotic
Unicellular
Animal-Like Protists (protozoans)
Pseudopods, Ciliates, Flagellates
Examples: Amoeba, Paramecia, Giardia
Plant-Like Protists (autotrophic)
Euglenoids, Dinoflagellates, Diatoms, Green/Red/Brown Algae
Fungus-Like Protists
Examples: Water molds, slime molds
Plant-Like
Water Mold
Slime Mold
Diatom
Euglena
Green Algae
Brown Algae
Dinoflagellates

19. Kingdom Fungi
All eukaryotic, multicellular, heterotrophic, sessile organisms
Includes: molds, mushrooms, rusts, lichens
Mycorrhizal associations allow plants to absorb more water and nutrients from the soil

20. Coniferophytes (Pine Trees)
Kingdom Plantae
Primitive Plants
Bryophyte (Moss)
Pteridophyte(Fern)
Complex Plants
Pteridophyte(Fern)
All eukaryotic, multicellular, autotrophic, sessile organisms
Produce their own food from sunlight and carbon dioxide
Common Phyla:
Bryophyta (mosses)
Pteridophyta (ferns)
Coniferophyta (conifers, like pine trees)
Angiospermophyta (angiosperms, like flowering plants
Coniferophytes (Pine Trees)
Angiosperm; Dicot
Angiosperm; Monocot

21. Porifera Ctenophora Cnidaria Nematoda Platyhelminthes
All eukaryotic, multicellular, heterotrophic, motile (most) organisms
Common Phyla:
Porifera (sponges, corral)
Cnidaria & Ctenophora (jellyfish and similar animals)
Platyhelmenthes (flat worms, tapeworms)
Nematoda (small unsegmented worms)
Platyhelminthes

22. Arthropoda Chordata Annelida Molluska Echinodermata
Mollusca (inc. clams, oysters, etc..)
Annelida (segmented worms)
Echinodermata (starfish and anemones)
Arthropoda (crustaceans, insects, spiders)
Chordata (those with spinal chords)
Molluska
Echinodermata

23. Human Classification Domain: Eukarya Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: Sapien

24. Using the Classification System
Field guides help identify organisms.
-they highlight differences between similar organisms (like trees)
Taxonomic Key (AKA Dichotomous Key)
-paired statements that describe the physical characteristics of different organisms

25. Taxonomic Key
1. Fruits occur singly Go to 3
1' Fruits occur in clusters of two or more Go to 2
2. Fruits are round Grapes
2' Fruits are elongate Bananas
3. Thick skin that separates easily from flesh Oranges
3' Thin skin that adheres to flesh Go to 4
4. More than one seed per fruit Apples
4' One seed per fruit Go to 5
5. Skin covered with velvety hairs Peaches
5' Skin smooth, without hairs Plums

26. Dichotomous Keys 1a. Organism has 4 legs Go to # 2
1b. Organism has more than 4 legs Go to # 20
2a. Organism has a tail Go to # 3
2b. Organism has no tail Go to # 35
3a. Organism has stripes Bengal Tiger
3b. Organism has no stripes African Lion
Used to help identify unknown specimen
Work by asking yes or no questions whose answers lead the reader to the correct taxa for the organism

27. Dichotomous Key Try this one:
1a. Organism walks on all 4 legs (quadruped) 2
1b. Organism walks on 2 legs (biped) 8
2a. Organism has visible fur 3
2b. Organism has no visible fur
3a. Organism lives in warm climates 7
3b. Organism lives in cold climates 4
4a. Organism has brown or black fur Ursus americanus
4b. Organism has white fur Ursus maritimus

28. Note Guide Who was Linnaeus? What are taxa?
How are organisms scientifically named?
What is the difference between the 3 domains? 1. 2. 3.
Name and describe the differences between the 4 kingdoms in Eukarya: 4.

29. Note Guide (pg. 2)
Name and describe (or give an example of) each of the 10 phyla in Animalia: 1. 2. 3. 4. 5. 6. 7. 8. 9.
10.
How would you fully classify a human?
What is the purpose of a dichotomous key?
How do you read a dichotomous key?