Levels of organization

Molecules

consist of two or more atoms held together by chemical bonds

Organelles

are structures with specialized functions within the cell

Cells

s are the smallest units that perform all functions of life.

Tissues

are groups of cells that work together to perform a specified function.

Organs

are “body parts” that carry out specific functions and are made up of multiple tissues

Organisms

are individual living systems.

Populations

are all of the organisms of a given species in an area. Ex: coyotes on campus, rats in a field, cockroaches in your home, etc.

Communities

are all of the different species within an ecosystem. Ex: coyotes, cacti, and tarantulas in the Sonoran Desert.

ecosystem

consists of both living and nonliving systems within a particular area.

biosphere

is all parts of the earth where life exists on earth