Overview
This lecture covers the history and development of the cell theory, highlighting the scientists and discoveries that shaped our current understanding of cells.
The Cell Theory
- The cell theory has three parts: all organisms are made of one or more cells; the cell is the basic unit of life; all cells come from preexisting cells.
- The theory is essential to understanding biology and the structure of living things.
Early Microscopy and Discoveries
- Zacharias Janssen, a Dutch spectacle maker, is credited with creating the first compound microscope in the early 1600s.
- Anton van Leeuwenhoek improved microscopes and discovered bacteria (which he called "animalcules") by examining dental scrapings.
- Robert Hooke coined the term "cell" after observing cork under a microscope, comparing the structures to monks' rooms.
Advancements in Cell Theory
- Matthias Schleiden, a botanist, concluded all plants are made of cells.
- Theodor Schwann found that all animals are made of cells and contributed to naming the Schwann cell.
- Schleiden and Schwann collaborated to unify their findings and develop the cell theory.
Controversy and Completion
- Schleiden believed cells formed spontaneously, but Rudolph Virchow, using Robert Remak’s research, showed cells arise only from other cells.
- Disputes and rivalries among scientists, such as Hooke vs. Newton and Virchow vs. Remak, influenced scientific progress.
Key Terms & Definitions
- Cell Theory — The framework stating all living things are composed of cells, the cell is the basic unit of life, and cells come from other cells.
- Microscope — An instrument that magnifies small objects, making cells visible.
- Animalcules — Leeuwenhoek’s term for microscopic organisms.
- Schwann Cell — A type of nerve cell discovered by Theodor Schwann.
Action Items / Next Steps
- Review the three parts of the cell theory for understanding and memorization.
- Research the contributions of each mentioned scientist for context.