The Organization of Life How do we organize living things?

Branches of biology Because biology is so vast, it is divided into many smaller sub-fields of study. Many of these areas of study focus on certain divisions of the natural world.

Molecules These are clusters or groups of atoms. Smallest unit of any compound.

Cells These are the smallest units of life. Contain several different molecules.

Groups of cells These are structures that are made up of cells. We will cover this in later units.

Organisms One individual living thing. May be unicellular or multicellular. Includes you and me!

Population A group of ONE specific organism. For instance, a flock of geese is a population.

Community ALL of the populations within a given area. All populations within a community interact with one another.

Ecosystem A single community, combined with all of the non-living factors in the area. Includes rocks, water, air. Non-living factors are abiotic. (“not living”) Living factors, such as a population, are biotic (“living”.

Biosphere All of the ecosystems on Earth. Biosphere means “living sphere”.