Levels of organization

Atoms – smallest unit of all matter Molecules – a few atoms put together with covalent bonds Macromolecules – very large molecules made up of hundreds or thousands of atoms http://biomodel.uah.es/en/model3/index.htm

Cells – the smallest units of life that are made up of cell organelles Cells – the smallest units of life that are made up of cell organelles. Cells specialize to perform all life functions.

TISSUES – groups of cells of similar structure that perform a particular, related function.

ORGANS: Structures of definite form and structure, comprising two or more tissues.

ORGAN SYSTEMS: an association of organs with a common function. There are several organ systems in the human (many animal) body: (know 3 examples) Circulatory Integumentary Excretory Sensory Respiratory Reproductive Digestive Muscular Immune Skeletal Nervous Endocrine

ORGANISM: The complex functioning of all the components above builds up the organism.

The following levels include groups of organisms POPULATION – a group of organisms that belong to the same species (ex. All white tailed deer in a forest) COMMUNITY – all living organisms that live in the same area and interact with each other. (all living organisms of the same forest)

ECOSYSTEMS – all living organisms and their nonliving environment in a given area. http://www.youtube.com/watch?v=TxfAVuarVTI&feature=related BIOSPHERE – all life forms and the environment that they live in on the planet.