Overview
This lecture introduces the biological levels of organization, explaining each level from cells to the biosphere and their significance in understanding living systems.
Biological Levels of Organization
- The cell is the basic, living unit of all organisms.
- Subcellular components like organelles, biomolecules, and atoms are smaller than cells but are not considered living units.
- Tissues are groups of similar cells working together for a function (e.g., cardiac muscle tissue).
- Organs are made up of multiple tissues performing specific tasks (e.g., heart).
- Organ systems consist of multiple organs working together (e.g., digestive system).
- An organism is an individual living being with organ systems (e.g., a human or platypus).
- A population is a group of the same species living and breeding together in an area.
- A community includes all populations of different species living together, considering only living (biotic) factors.
- An ecosystem encompasses a community plus abiotic (nonliving) factors like rocks, water, and temperature.
- A biome is a group of similar ecosystems found in various geographic locations (e.g., desert biome, rainforest biome).
- The biosphere is the sum of all biomes, representing all areas on Earth where life exists.
Key Terms & Definitions
- Cell — the smallest living unit in all organisms.
- Tissue — groups of similar cells with a shared function.
- Organ — structure made of tissues performing specific functions.
- Organ system — group of organs working together for a purpose.
- Organism — an individual living being.
- Population — members of the same species living in one area.
- Community — all living populations in an area, excluding abiotic features.
- Ecosystem — a community plus abiotic (nonliving) environmental factors.
- Biome — collection of similar ecosystems across the globe.
- Biosphere — all areas on Earth where life exists.
Action Items / Next Steps
- Review and memorize the order of biological levels of organization.
- Prepare to identify examples of each level in upcoming assignments.