1. Taxonomy Biological Classification

2. Taxonomy
The branch of biology that deals with the classification of living organisms
Dividing things with common characteristics into groups or categories
Allows us to organize, track, and identify organisms in the living world

3. History
Aristotle, the ancient Greek philosopher, divided all living organisms into 2 categories: plants and animals
Plants were stationary and used photosynthesis to make food
Animals were motile and ingested their food
Kingdom Plantae
Kingdom Animalia

4. The system was simple, but problems still arose
Not all organisms fit into one category or the other
Coral, sponges, mushrooms are stationary but do not photosynthesize
Single-celled organisms that move but also photosynthesize (euglena)

5. The 5 Kingdom System
Viruses
(nonliving)

6. The Big Split
Later it was found that there were two distinct groups in the Kingdom Monera that were not very genetically related
The Kingdom Monera was split into two:
Kingdom Eubacteria & Kingdom Archaea
Eubacteria
Archaea

7. Present Day: 6 Kingdoms

8. Number of species per Kingdom
The 6 Kingdoms
Number of species per Kingdom
(p. 382)

9. The 3 Domains Some taxonomists classify organisms using domains.
Domains are based on RNA (ribonucleic acid)
The 3 domains are: Domain Bacteria, Domain Archaea, and Domain Eukarya

10. Fundamental difference:
Members of the Domain Eukarya are more closely related to the Domain Archaea than to the Domain Bacteria.
Fundamental difference:
Domain Eukarya = eukaryotic
Domain Bacteria and Archaea = prokaryotic

11. Eukaryotes vs. Prokaryotes
Kingdom Bacteria & Archaea
Kingdom Protista, Fungi, Plantae, & Animalia
Very small (~0.1-10µm)
Large in comparison (~ µm)
Circular DNA. No nucleus.
1 chromosome.
DNA is located in a nucleus.
Multiple linear chromosomes
Cell division NOT by mitosis or meiosis (binary fission)
Cell division by mitosis & meiosis
Asexual reproduction is common
Sexual reproduction is common
Mostly unicellular organisms
Mostly multicultural organisms
No membrane-bound organelles
Membrane-bound organelles
Anaerobic (do not require oxygen)
Most are Aerobic (require oxygen)

12. Eukaryotes vs. Prokaryotes

13. Homework
Read p
P. 384 #1-7

14. King Phillip Came Over For Good Spaghetti
Hierarchy of Groups
The 6 Kingdoms are a great start at classifying living things
But they are very broad, biologists need more specific details in order to identify organisms
Carl Linnaeus, the father of taxonomy, developed a system of classification that is still used today
King Phillip Came Over For Good Spaghetti

15. Binomial Nomenclature
Linnaeus developed a system for naming species
Whether classified by kingdoms or domains, each species as its own unique name
The name has two parts:
Genus (capitalized) followed by species (not capitalized)
Homo sapiens (humans)
Felis domesticus (house cat)
Mephitis mephitis (skunk)
Italicized or underlined
Latin

16. Dichotomous Keys
Are used to identify similar organisms (often within the same family or genus)
Have numbered steps; at each step there is a choice between two characteristics (usually opposites)
Each step finishes with either an instruction to go to another step, or an answer which identifies the organism
The number of pairs of clues is one less than the number of organisms to be identified

17. Homework
Read p
P. 396 #1 & 5
Shark & Ray Dichotomous Key (Handout)
Fairytale Creature Dichotomous Key Poster