Levels of Organization in Biology Levels of Organization

Levels of Organization in Biology

Levels of Organization Animation link

Atom The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons.

Molecule • A group of two or more atoms held together by chemical bonds

Organelle An organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer. The name organelle comes from the idea that these structures are to cells what an organ is to the body.

Cell • The cell is the basic structural and functional unit of all known living organisms. • It is the smallest unit of life that is classified as a living thing. • Is often called the building block of life

Tissue • A group of biological cells that perform a similar function

Organ • A collection of tissues joined in a structural unit to serve a common function

Organ System • a group of organs that work together to perform a certain task. Examples: circulatory system, the respiratory system, the nervous system, etc.

Organism • Single individual

Population • Group of organisms of same species that interbreed and live in the same place at the same time • Compete for resources

Community • Many interacting populations • Change in one population causes changes in the others

Ecosystem • Interacting populations and the abiotic factors • Types: Terrestrial Freshwater Saltwater

Biosphere • The portion of the earth that supports life