Overview
This lecture introduces the study of biology, focuses on the definition of life, and explains the hierarchical organization of living organisms from atoms to organ systems.
Introduction to Biology
- Biology is the scientific study of life.
- The prefix "bio-" means life, and "-logy" means the study of.
Defining Life
- Living things share five main characteristics: organization, energy use, response, reproduction, and adaptation.
- These characteristics distinguish living things from non-living things.
Levels of Biological Organization
- Atoms are the basic building blocks of all matter.
- Molecules form when atoms bond; they can be simple (oxygen gas) or compounds (sugar, proteins).
- Organelles are formed from molecules and have specific functions within cells.
- Cells are the smallest living units and can reproduce independently.
- Tissues are groups of cells with specialized functions.
- Types of tissues include epithelium (covers surfaces), connective tissue (binds tissues), nervous tissue (responds to stimuli), and muscle tissue (enables movement).
- Organs are structures made from different tissues that perform specific functions.
- Organ systems consist of multiple organs working together; humans have 11 body systems.
- The organism is the most complex level, made up of organ systems.
Key Terms & Definitions
- Biology — the scientific study of life.
- Atom — the smallest unit of matter.
- Molecule — a group of bonded atoms.
- Compound — a molecule composed of different elements.
- Organelle — a specialized structure within a cell.
- Cell — the smallest living unit of matter.
- Tissue — a group of similar cells performing a specific function.
- Organ — a structure composed of multiple tissue types.
- Organ system — a group of organs working together.
- Organism — an individual living entity.
Action Items / Next Steps
- Jot down and email any questions to the instructor.
- Review and remember the five characteristics of life.
- Recall the levels of biological organization for future lessons.