1. Levels of Organization & Body Systems
Biology

2. Level 1 - Cells
Cells – All living things are made of one or more cells

3. Level 2 - Tissues
Cells that perform the same function work as a team to form tissue.
Examples: muscle tissue, cardiac tissue, etc.

4. Level 3 - Organs
Tissues that have roughly the same function work together to form organs.

5. Organs of a Plant
Plants have organs too!

6. Level 4 – Organ Systems
Organs can work together to perform specific functions by being part of an organ system. They often work in pairs.

7. Organ Systems Continued
Digestive System – Breaks down food and absorbs nutrients
Excretory System – Processes and removes wastes
Respiratory System – brings in O2 and removes CO2
Circulatory System – transports oxygen and nutrients to cell; transports carbon dioxide and wastes away from cells; in both plants and animals; in plants, it is called vascular tissue
Skeletal System – the bones of the body; works in conjunction with the muscular system to control movement
Muscular System – the muscles of the body; works in conjunction with the skeletal system to control movement
Immune System – battles your body’s invaders in an attempt to keep you from getting sick
Lymphatic System – consists of lymph nodes (glands) and white blood cells that collect and carry invaders (viruses & bacteria) out of the body
Endocrine System – constantly monitors the status of the body and sends hormones and signals throughout the body; works on a feedback loop; ex. – the endocrine system senses when there is sugar in the blood and releases insulin (a hormone) in response
Reproductive System – responds to sexual hormones sent out by the endocrine system; makes sperm and eggs, even in plants

8. This Organ System Controls Them All!
Nervous System - sends and receives signals between nerves throughout the body, and the brain.

9. Level 5 - Organism
All the organ systems of the body work together to form a fully functioning organism.