The Organization of Living Things

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.

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

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

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

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

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

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

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

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

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

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

Body Systems

Body Systems Reproductive and endoctrine

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

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).