It may be hard to imagine that everything around you, including you, is made up of spinning subatomic particles—protons, neutrons, and electrons. But it is true. All forms of matter can be classified in levels that increase in complexity, starting with the atom.

Directions: Watch the Levels of Organization animation to review the levels of organization, from the atom to the biosphere.

All images from Microsoft Word 2010.

All images from Microsoft Word 2010.

For levels of organization above an organism, there are the following:

• Population: a group of freely interacting and interbreeding organisms of the same species in the same area.
• Community: all of the populations of different species living and interacting together in the same area.
• Ecosystem: all of the living (biotic), and physical, non-living (abiotic) factors in an area.

All of the living things that are above, on, or below the Earth's surface represent the biosphere.

Directions: Watch What is a Salt Marsh? and answer the related questions in the Journal Activity.