1. Individual: A single organism, such as a deer, a tree, or a bacterium. This is the most basic level of ecological organization.

2. Population: A group of individuals of the same species living in the same area at the same time. For example, a population of deer in a forest.

3. Community: All the different populations of organisms living and interacting in a particular area. This includes plants, animals, fungi, and bacteria. For example, the community in a pond would include fish, frogs, plants, algae, and bacteria.

4. Ecosystem: A community of organisms and their physical environment, including the nonliving components like air, water, soil, and sunlight. This is where energy flow and nutrient cycling occur. For example, a desert ecosystem or a rainforest ecosystem.

5. Biome: A large-scale collection of ecosystems that share similar climate, vegetation, and animal life. Examples include deserts, grasslands, forests, and tundra.

6. Biosphere: The entire part of the Earth that supports life, including all of the biomes and the atmosphere, hydrosphere, and lithosphere. This is the highest level of ecological organization.

Think of it like a set of Russian nesting dolls, each level encompassing the ones below it.