Levels of Biological Organization

organelles

parts of a cell

cell

• basic unit of life

• smallest living unit

• carries out basic functions

tissue

• group of similar cells

• cells working together

• performs specific function

organ

• group of tissues

• performs a specific job

• essential for survival

organ system

• group of organs

• organs working together

• maintains body functions

organism

• a single living thing

• made up of one or more organ systems

• has the ability to grow, reproduce, and respord to the environment

population

• group of the same species

• lives in the same area at the same time

• competes or cooperates for resources

community

• different populations together

• made up of various species living in one area

• interacts and depends on each other

ecosystem

• living + nonliving components

• community + environment (air, water, soil, sunlight)

• energy flows and nutrients cycle

biome

• large area with a specific climate, plants, and animals adapted to that environment

• shaped by temperature, rainfall, and soil

biosphere

• all life on earth

• includes all ecosystems and biomes

• all living things + their environments

• earth’s life-supporting zone