1. Classifying Living Things

2. Classifying Living Things
Scientists identify, define, and name species of organisms
A species is a group of organisms that share similar physical features, are genetically similar, and can reproduce with one another to produce a viable offspring.
Why this is important
Accurately names organisms
Prevents duplicated names
Prevents misnomers (E.g. starfish & jellyfish arent’ fish)
Universal language (latin)
To show evolutionary relationships

3. Taxonomy
An organism is a living thing that is capable of reproducing, responding to stimuli, and growth.
All organisms in the world can be classified into a grouping system known as Taxonomy.
Taxonomy was initially created by Carl Linnaeus.

4. Taxonomy How many species are there?
About 1.4 million have been identified
Nearly 2/3 are insects
Scientists estimate million (meaning most aren’t even discovered yet)

5. Thought Experiment
Imagine you were in charge of naming all living organisms. How might you divide these organisms?

6. Taxonomy Was created by examining physical and structural features :
The more features in common, the closer the ancestral relationship
Binomial nomenclature is the system used to name every organism.
E.g. Canis lupus (Grey Wolf)

7. Binomial Nomenclature
Binomial nomenclature is usually based on a characteristic of the organism
E.g. Castor canadensis (i.e. it is from Canada)
The first word Castor is known as the genus name and the second word canadensis is known as the species name.
*Note that the genus name is always capitalized while the species is not. Also the entire name is italicized.*

8. Levels of Classification
The Genus and Species names are part of the 8 ranks
The image on the left shows the different levels of classification (i.e. ranks)
If two organisms have the same genus name they are more similar than two organisms with the same phylum name
Dearest King Philip Came Over For Good Spaghetti

9. Levels of Classification
Taxon
Side Note: Taxon (Plural = Taxa) is a specific rank for organisms
I.e. Rank = Kingdom Taxa = Animalia

10. E.g. Human Classification
The common name is often used to name a species.
The Kingdom level is the most general while the Species is most specific
Common Name: Humans
Scientific Name: Homo sapiens
Classification Level
Classification Name
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Family
Hominidae
Genus
Homo
Species
sapiens

11. Which two organisms are most closely related?
Classification Level
Humans
Grey Wolf
Brown Bear
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Carnivora
Family
Hominidae
Caninae
Ursidae
Genus
Homo
Canis
Ursus
Species
sapiens
lupus
arctos

12. Levels of Classification
There are 3 Domains and 6 Kingdoms
The Domain: First level of Classification
This level breaks down living organisms into the major categories of:
Bacteria
Archaea
Eukarya Eukaryotes

13. Prokaryotes Do not have a nucleus Do not have well defined organelles
E.g. Bacteria and Archaea

14. Eukaryotes
Have a nucleus
Have well defined membrane-bound organelles

15. The Kingdom Taxa
The six Kingdom system is commonly used: bacteria, Archaea, Protista, Fungi, Plantae, Animalia

16. The Other Taxa
Taxa for the Grey Wolf (Canis lupus)

17. What Makes a Species a Species
Lions and tigers can reproduce together and make a liger or tigon. Why then are they considered different species? +

18. What Makes a Species a Species
Recall: A species is a group of organisms that look similar and can can interbreed under natural conditions to produce fertile offspring.
In other words, their children can grow and reproduce.
Ligers and tigons cannot reproduce

19. Video of Liger

20. Homework
Read pages #2-6 (p.13); Activity 1.1 (p.13); #2-3, 6-7, (p.16); #9,11(p.19); #1-2, 4-7, 9 (p.30)