Levels of Organization in Biology

The smallest unit of matter that cannot be broken down into anything simpler by chemical means.

The smallest units of most compounds formed by the chemical bonding of atoms.

The smallest unit of life - collections of living matter enclosed by a barrier that separates them from their surroundings.

Groups of similar cells that perform a particular function.

Groups of organs that work together to perform closely related functions.

Groups of tissues that work together to perform closely related functions.

Living things composed cells (multicellular organisms).

Groups of individuals of the same species that live in the same area.

Groups of all the organisms that live in a particular place, together with their nonliving environment.

Groups different populations that live together in a defined area.