1. Theories vs. Laws Cell Theory
Scientific Theories
Theories vs. Laws
Cell Theory

2. How to take Biology notes
Cornell Notes:
Set-up your paper
Essential Question (across the top): What is cell theory and how was it formed?

3. What is a theory?
Theories provide powerful evidence-based explanations for scientific occurrences, such as gravity, evolution, the creation of the universe, general relativity, quantum mechanics, and more.
Theories are based on hypotheses that have been well-tested by many scientific investigations.
Theories use all the available current evidence to explain the world around us.

4. What makes a theory different from a law?
Laws are statements that describe observable facts that have been seen over and over again without variation.
Theories do not “grow up” into laws – they are two separate things.
Both laws and theories are powerful scientific tools backed up by significant amounts of evidence.

5. Cell Theory
Cell theory is a scientific explanation for cells that has undergone multiple experiments and has significant evidence.
Cell theory is the result of the accumulated research of five different scientists:
Hooke
Leeuwenhoek
Schleiden
Schwann
Virchow

6. How did cell theory come to be?
Robert Hooke (1665):
used a compound microscope to examine a cork
Identified and named microscopic components “cells”

7. How did cell theory come to be?
Anton van Leeuwenhoek (1674):
Made a more powerful single-lens microscope & saw cells in great detail
Observed the first living cell

8. How did cell theory come to be?
Matthias Schleiden (1838):
Studied plant tissue using compound microscopes
Proposed that plants are made of cells

9. How did cell theory come to be?
Theodor Schwann (1839):
Studied animal tissue using compound microscopes
Proposed that animals are made of cells
Published the first version of cell theory

10. How did cell theory come to be?
Rudolf Virchow (1855):
Proposed that all cells come from other cells

11. What does Cell Theory say?
The three major principals of cell theory are:
All organisms are made of cells
All existing cells are produced by other living cells
The cell is the most basic unit of life