This document discusses the different levels of organization in multicellular organisms. It begins by explaining that multicellular organisms develop from a single cell through cell differentiation into various cell types, tissues, organs and organ systems. The first level is cells, which can become specialized. The second level is tissues, groups of cells that work together. The third level is organs, made of multiple tissue types. The fourth and highest level is organ systems, groups of organs that work together to perform important functions for the organism.
2. Key Concept
As multicellular organisms develop, their
cells differentiate (change & separate) to
form different levels of organization
3. Key Concept
Why it Matters: so
organisms like humans
(we are multicellular) can
have different kinds of
cells, tissues, organs, and
organ systems
4. Unicellular Organisms
“uni-” = one
Prokaryotes are unicellular organisms
Some algae, some protists, and some
eukaryotes (yeasts), are unicellular
Can individually do everything they need to
stay alive
5.
6. Benefits over multicellular organisms:
Need fewer resources
Can live in harsher conditions
8. Multicellular Organisms
Start as a single cell many cells cells
differentiate (change) into different types of
cells cells group together to form tissues
15. Levels of Organization
1st Level: Cells
2nd Level: Tissues
3rd Level: Organs
4th Level: Organ Systems
Cells Tissues Organs Organ Systems
16. 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
17. 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
18. Level 3: Organs
Organ = structure that is made up of 2 or more
tissues working together to get a specific job done
19. Level 3: Organs
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
20. Level 4: Organ Systems
Organ system = group of organs working
together to perform a specific function
Each organ system has a specific job
Ex: Digestive system is made of several organs
including the stomach and intestines
21. 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