1. Introduction to Classification
What is meant by classification?
-To group living things based on similarities.
Why classify living things?
Scientific reasons….
Medical reasons…
Organizational reasons
Taxonomy is the science of grouping and naming organisms.

2. Aristotle’s system
ARISTOTLE -
*4th century BC (384 to322 BC) *Greek philosopher
2000 years ago Aristotle divided living things into either plants or animals .
Animals were divided into groups based on where they lived; land, water, or air. They were also grouped based on whether they were blooded or bloodless.
The plants were divided into groups based on differences in their stems.

3. Problems with his System
Using Aristotle's 3-group system - land, air water:
Some possible Answers: a. walking - cat, dog, human, etc. b. flying - bird, bat, butterfly, etc. c. swimming - fish, whale, manatee, etc.
Do you see any possible conflicts here?
What about a duck or an alligator?

4. Carolus Linnaeus
He devised a system of grouping organisms into hierarchical categories based on physical characteristics, such as form or structure.
For example, Linnaeus's plant taxonomy was based solely on the number and arrangement of the reproductive organs on a plant.
Overall this proved to be a better system however it had some problems that resulted in many groupings that seemed unnatural.

5. Binomial Nomenclature
Linnaeus devised this system:
The genus name is written first (always Capitalized).
The species name is written second (never capitalized).
Both words are either italicized or underlined.
Eg.. Homo sapiens or Homo sapiens

6. Phylogeny
The four lines of evidence used to create phylogenetic trees are:
The fossil record
Morphology
Embryological patterns of development
Chromosomes and DNA

7. The Fossil Record: Anatomical similarities or patterns in relation to time on the evolutionary scale can be invaluable.
Similarly, relationships in the Morphology (morph refers to form) of the creatures we see today allow us to categorize organisms based on these facts.

8. Embryological patterns of development, and Genetic Info/ DNA -
The changes that an organism undergoes during its development can leave clues to its evolutionary past.
The amount of genetic material that two organisms share relates to how close they are on the phylogenetic tree

9. The major classification levels, from largest group to smallest (several of these have subdivisions)
Kingdom Phylum Class Order Family Genus Species
“King Philip called out for Greek salad”

10. Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gadiformes
Family: Gadidae
Genus: Gadus
Species: Gadus morhua

11. Idenitifying Marine Organisms
Some things we know by sight: fish, crab
These words are different in other languages: poisson, fisch, pescado, pesce.
Scientists all over the world know that Gadus morhua is Atlantic cod.
There are many types of cod in the Genus Morhua but only one species:
Gadus morhua

12. Species
A group of organisms that look alike and can interbreed under natural conditions to produce fertile offspring.
When similar species are in close contact, interbreeding can take place for example, dolphin and whale to produce a wolphin. These animals are infertile and can’t have offspring so they are not new species.