Organ. Many tissues constitute an organ. For example, groups of cardiac tissue constitute the heart.
Organ system. Group of organs made up an organ system. For example, brain and spinal cord made up the nervous system.
Organism. Different organ system constitute an organism. Respiratory system, nervous system, digestive system, excretory system, etc. constitute an organism.
Population. Groups of organisms made up a population. For example, if 1 billion people live in the US, then these people constitutes the population of the nation.
Community. Populations constitute a community. For example, a population constituting many players of different sports constitutes the sport community.
Ecosystem. Many communities made an ecosystem.
Biosphere. Finally, all ecosystems made up the biosphere.
