1. Scientists also Classify Living Organisms
Cats, dogs, mammals, pets, friends………

2. 1. Whether they are unicellular or multicellular
The most basic classification system is based on Domains and Kingdoms. Organisms are classified into Domains or Kingdoms based on these characteristics:
1. Whether they are unicellular or multicellular
2. _____________________________________
3. Whether they have a cell wall or cell membrane
4. _____________________________________
5. _____________________________________
6. Whether they reproduce sexually or asexually
7. How they tolerate heat, salt, or other extreme conditions
See Vocabulary Activity in this Module.

3. Taxonomy
_______________________________________________________________________________________

4. Three Domains of Life
Monophyletic; one c.a.

5. • Domain Archaea Domain Bacteria Domain Eukarya
_________________________________
Contains 1 kingdom – the Archaebacteria
Domain Bacteria
Includes other members of old kingdom Monera
___________________________
Domain Eukarya
Includes all kingdoms composed of organisms made
up of eukaryotic cells
– Protista
– ______________
– Animalia

6. Prokaryotes Includes the kingdoms Archaea & Bacteria
Oldest, structurally-simplest, and most abundant forms of life
Important decomposers and symbionts
True bacteria; Existed on Earth for 1 billion years before the Eukaryotes appeared

7. Prokaryotes ______________
No membrane-bound nucleus; instead a single circular chromosome made of DNA
_____________________________
Photosynthetic bacteria utilize oxygen or chemical compounds, such as sulfur
Although they can transfer genetic material via their plasmids (horizontal gene transfer), however not considered reproduction

8. Prokaryotic Cell Structure
Three basic forms:
_________________
Coccus - sphercal or ovoid-shaped
__________________

9. Prokaryotic Cell Structure
Prokaryotes have a tough cell wall and other external structures
Cell wall consists of _______________; a rigid network of polysaccharide strands cross-linked by peptide side chains; unique to Bacteria
Maintains the shape of the cell and protects it from swelling and rupturing

10. Prokaryotes can have 1 or more flagella (much less complex than in Eukaryotes)
Some Prokaryotes possess pilli, which helps
fasten cell to host membrane

11. Domain Archaea
Once considered a subdivision of the _________________, now its own domain
Like all prokaryotes, Archaea are single-celled microorganisms that lack a nucleus and membrane-bound organelles
Best known for the “extremophiles” – Archaea which _______________________environments

12. Archea - Extremophiles
Thermophiles – thrive at 60-80°C (>176°F!)
Acidophiles – thrive at pH at or below pH 3
Xerophiles – grow in extremely dry conditions
Halophiles – require extremely high concentrations of salt

13. Archaea differ from Bacteria in numerous ways
Plasma membranes are made of different kinds of lipids
RNA and ribosomal proteins more like those of Eukaryotes
_________________
(photosynthetic: cyanobacteria and lithotrophs (Nitrosomonas which oxidizes ammonium)
Photosynthetic

14. Domain Bacteria Two types: _____________________
Gram-positive
Gram negative
_____________________
Refers to the Gram Stain (purple dye)
Gram-positive bacteria – possess a thicker peptidoglycan cell wall; _______________
Gram-negative bacteria – contain less peptidoglycan; ________________

15. Gram-positive and negative

16. Bacterial Conjugation
Transfer of genetic material
Horizontal gene transfer
NOT sexually (no gametes)
Involves cell to cell contact; does not involve fusion of gametes and the creation of a zygote
There is not an equal exchange of genetic material, merely the transfer of genetic material from a donor cell to a recipient
Often beneficial to the recipient cell – inc. antibiotic resistance or the ability to utilize a new metabolite
Transformation – genetic material transfer that does not involve cell to cell contact; direct uptake from environment
Tranduction – incorporation of new DNA from virus

17. Basic Classification Kingdoms:
The Domains can also be split into Kingdoms which further divide the organisms by their characteristics.

18. Domain Eukaryota (Eukarya)
__________
Very diverse
Unicellular or multicellular
________________
Reproduce sexually or asexually
Can be split into 4 Kingdoms-
Protista
Fungi
Plantae
Animalia

19. The 4 Kingdoms in Eukaryota
Protista
____________________________
_____________________________
Can be infectious agents
Examples:
Amoeba
Algae
Daphnia
Plasmodium (causes malaria)
Plantae
Multicellular green plants
Autotrophic through photosynthesis
________________
Mosses
Ferns
Trees
Flowering Plants
Fungi
_________________
__________________
Decomposers
Mushrooms
Athlete’s foot
Bread Mold
Animalia
Multicellular Animals
______________
Insects
Spiders
Crabs
Birds
Humans

20. D O M A I N S K I N G D O M S

21. How would you classify these?
A organism that can exist in extremely hot temperatures and that is made of only one cell with no nucleus A green organism growing from the ground that is multicellular and that undergoes photosynthesis; its cells have nuclei and cell walls

22. Try two more:
This microscopic and one-celled organism lives in colonies with millions of others like it. It does not have a nucleus and cannot survive in extreme conditions. It could be an infectious agent. This organism is a multicellular decomposer; its cells have nuclei.