1. The Organization of Living Things

2. Key Concept I Can: discern levels of organization in organisms
trace organization from atoms to molecules to cells to tissues to organs to organ systems to organisms.
understand the levels of organization of living systems in terms of structures and functions.

3. Unicellular Organisms
“uni-” = one
Prokaryotes are unicellular organisms
Some algae, some protists, and some eukaryotes (yeasts), are unicellular
Can still do everything they need to stay alive
Benefits over multicellular organisms:
Need fewer resources
Can live in harsher conditions

4. Multicellular Organisms
“multi-” = more than one
Plants, animals, some protists, and most fungi are multicellular
Start as a single cell  many cells  cells differentiate (change) into different types of cells  cells group together

5. Levels of Organization
Atom
Molecule
Cell
Tissue
Organ
Organ System
Organism Level

6. Multicellular Characteristics
Larger size = have less predators and have more options of things to eat
Longer life – organism will continue to live even if a single cell dies
Specialization – each type of cell has a specific job, making the organism more efficient

7. Levels of Organization
1st Level: Cells
2nd Level: Tissues
3rd Level: Organs
4th Level: Organ Systems
Cells  Tissues  Organs  Organ Systems

8. Levels of Structural Organization
Organ level - consists of two or more types of primary tissues that function together to perform a particular function or functions
Example: Stomach
Inside of stomach lined with epithelial tissue
Wall of stomach contains smooth muscle
Nervous tissue in stomach controls muscle contraction and gland secretion
Connective tissue binds all the above tissues together
System - collection of related organs with a common function, sometimes an organ is part of more than one system
Organic level - one living individual

9. Level 1 : Cells Cells can be specialized (have a certain function)
Function = job
Function is related to the cell structure
Structure = how parts of the cell are put together
Shape
Material it’s made from
Structure of a brain cell is different from muscle cell

10. Level 2: Tissues
Tissue = group of cells that work together to do a specific job
Ex: Heart muscle tissue is made of heart muscle cells
Animals have 4 types of tissue: nerve, muscle, connective, protective
Plants have 3 types of tissue : transport, protective, ground

11. Level 3: Organs
Organ = structure that is made up of 2 or more tissues working together to get a specific job done
Ex: Stomach – muscle tissue moves food, special tissues make chemicals to digest food, connective tissue holds stomach together, nervous tissue sends messages back and forth between the stomach and brain

12. Level 4: Organ Systems
Organ system = group of organs working together to perform a specific function
Each organ system has a specific job
Do not act in isolation from one another
Human body has 11 systems

13. Body Systems

14. Body Systems
Reproductive and endoctrine

15. Structure of Animals Cells -basic unit of an animal’s structure
-become specialized
_______________________________
Tissues
-made of cells that work together to perform a specific function
__________________________________________
Organs
-made of different types of tissues that work together to perform a specific function
____________________________________________________
Organ Systems
-made of organs that work together to perform a specific function
_____________________________________________________________
Organisms

16. Activity 1: Use the descriptions on your handout to determine which level of organization (organelle, tissue, organ, system, etc.) is being described. Write the level of organization in the parentheses provided above the picture.
Activity 2: After reviewing the different levels of organization, use your handout to help you fill in the following chart by selecting the example that meets the requirement listed. (Hint: You will need to use “epithelial tissue” twice to complete the chart).