Overview
This lecture explains the hierarchy of biological organization, from atoms up to the biosphere, and emphasizes the concept of emergent properties at each level.
Levels of Biological Organization
- Life exists in a hierarchical structure from atoms to the entire biosphere.
- Atoms are the fundamental unit of matter.
- Atoms combine to form molecules via chemical bonds.
- Larger, complex molecules in living organisms are called biological macromolecules (e.g., DNA, proteins, lipids, carbohydrates).
- Macromolecules can be further broken down into monomers (smaller molecular units).
- Molecules make up organelles, specialized structures within cells.
- Cells are the basic structural and functional unit of life.
- Groups of similar cells form tissues with related functions.
- Tissues combine to form organs with specific tasks (e.g., heart, brain).
- Organs group together into organ systems (e.g., circulatory, musculoskeletal systems).
- An organism is an individual living being composed of multiple organ systems (in multicellular species).
- Organisms of the same species in an area form a population.
- Multiple populations living together in an area form a community.
- An ecosystem includes all living organisms in an area plus the non-living environment (abiotic factors).
- The biosphere encompasses all ecosystems on Earth.
Cellular Components
- All cells have a plasma membrane that separates and regulates interaction with the environment.
- Cytoplasm is the fluid interior of the cell containing organelles.
- All cells possess a genome (DNA) carrying genetic information.
- Ribosomes in cells synthesize proteins essential to life.
Emergent Properties
- Emergent properties are new features or behaviors arising at each level of organization that are not present at lower levels.
- Example: Heart cells cannot pump blood alone, but organized as an organ, they can.
- Example: Single nucleotides cannot store genetic info, but organized as DNA, they can.
Key Terms & Definitions
- Organism — An individual living being.
- Organ System — A group of organs performing a common function.
- Organ — Structures made of tissues working together for a function.
- Tissue — Groups of similar cells with related functions.
- Cell — The basic structural and functional unit of life.
- Organelle — Specialized structures within a cell with specific functions.
- Molecule — Two or more atoms bonded together.
- Macromolecule — Large molecules (like DNA or proteins) found in living organisms.
- Monomer — Small molecular units forming larger molecules.
- Population — Group of same-species organisms living in an area.
- Community — All populations in a particular area.
- Ecosystem — Community plus non-living environment.
- Biosphere — All ecosystems on Earth.
- Emergent Property — A feature that arises at a higher organizational level, absent at lower levels.
Action Items / Next Steps
- Review the levels of biological organization for upcoming discussions.
- Prepare to study emergent properties in more detail throughout the semester.