1. Classifying Organisms

2. Classification- putting things into groups based on shared characteristics
There have been many different ideas about how to classify living things.
Aristotle placed all organisms into 2 large groups-
plants and animals

3. Linnaeus’ System Linnaeus founded modern taxonomy.
Taxonomy- the science of describing , classifying , and naming living things
Based on 7 hierarchical categories
Simplified the naming of living things by giving each species a two-part specific name “Binomial nomenclature”

4. Binomial Nomenclature
Genus
Species
Felis domesticus
In a scientific name, the first part of the name is the organism’s genus. Similar species are grouped into one genus. Ex: Felis
The second part of the name identifies the species- a group of organisms that have similar traits and are able to produce fertile offspring.

5. Binomial Nomenclature
Panthera tigris
Panthera leo

6. Classification Today
Taxonomists use an eight-level system to classify living things based on shared characteristics.
The more characteristics the organisms share, the more closely related the organisms may be.

7. Levels Of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

9. DOMAINS Every living thing is classified into one of the 3 Domains:
Archea
Bacteria
Eukarya

10. DOMAIN 1: ARCHAEA ARCHAEBACTERIA Unicellular prokaryotes
Often live in harsh environments
some produce food by chemosynthesis (energy obtained from places other than the sun)

11. DOMAIN 2: BACTERIA Unicellular prokaryotes
Have a Cell wall and membrane
Most abundant organisms

12. DOMAIN 3: EUKARYA EUKARYOTES
Complex cells; nuclei and organelles in cells
Some are unicellular
Some are multicellular
The domain Eukarya is divided into 4 Kingdoms:
Protista
Fungi
Plantae
Animalia

13. Eukarya: Protista
One celled or Multicellular organisms that can either be plant-like, animal like, or both
Algae, Amoebas, Paramecium , Euglena

14. Eukarya: Fungi Multicellular Cell wall Does not perform photosynthesis
Absorbs nutrients
Reproduce using spores.

15. Eukarya: Plantae Cell wall Perform photosynthesis
Vascular vs. nonvascular
Flowering vs. nonflowering

16. Eukarya: Animalia Multi-cellular organisms that lack cell walls
Range from simple to complex
Invertebrates- Do not have a backbone
Worms
Sponges
Jelly Fish
Mollusks
Insects
Vertebrates – Have a backbone
Fish
Amphibians
Reptiles
Birds
Mammals

18. Classification Tools

19. Dichotomous Key
A series of descriptions arranged in pairs that can be used to identify an unknown organism
The chosen descriptions leads to another pair of descriptions or to the identification of the organism

20. Dichotomous Key

21. Cladogram
A branched diagram that shows the relationships among organisms
New characteristics appear before each branch