* Atom: The basic unit of matter. Grizzly bears are made up of atoms like any other living thing.
* Molecule: Two or more atoms bonded together. Examples include water (H2O) and proteins.
* Organelle: A specialized structure within a cell that performs a specific function. Examples include mitochondria (energy production) and the nucleus (containing DNA).
* Cell: The basic unit of life. Grizzly bears, like all living organisms, are made of cells.
* Tissue: A group of similar cells working together to perform a specific function. Examples include muscle tissue, nervous tissue, and connective tissue.
* Organ: A structure made up of different tissues working together to perform a complex function. Examples include the heart, lungs, and stomach.
* Organ System: A group of organs working together to perform a major life function. Examples include the digestive system, the circulatory system, and the nervous system.
* Organism: A complete living being. In this case, a grizzly bear.
* Population: A group of the same species living in the same area. A population of grizzly bears in Yellowstone National Park.
* Community: All the different populations of organisms living in the same area. The grizzly bear community in Yellowstone, including other animals like elk, wolves, and birds.
* Ecosystem: The community of organisms interacting with their physical environment. The entire Yellowstone ecosystem, including the grizzly bears, the forest, the rivers, and the climate.
* Biome: A large-scale ecosystem characterized by specific climate and vegetation. The North American Boreal Forest biome, where many grizzly bears live.
* Biosphere: All the living things and their environments on Earth. This is the broadest level of organization.
Let me know if you'd like to learn more about any of these levels!