Catalyst

1. What does it mean to be unicellular and multi-cellular?

2. What is homeostasis? Give an example.3. What do the following roots mean?– “bio”– “homeo”– “ology”– “uni”

History of Science: Cell Theory

Ms. KlinkhachornSeptember 30, 2009

Early Beliefs – The Four Humors

• Idea of balancing the fluids in the body– Imbalance resulted in illness and personality problems– Each fluid associated with a season of the year, natural

elements, personality traits, and qualities• Knew about tissues and organs, but didn’t understand

them• The Four Humors – Yellow bile – Black bile– Phlegm– Blood

Four Humors

• Humor Disorders– Yellow bile: easily angered, irritable – Black bile: depressed in spirits– Blood: Optimistic, enthusiastic, excitable– Phlegm: apathetic

Treatments

What invention led to the discovery of the cell?

Microscopes

• Something that is microscopic is too small to be seen with just the eye alone

• First microscopes come about during the early 1600s– Advancing technology helps to extend the human

senses

Historical Video

• What did Robert Hooke do for biology?• Why are cells called cells?• What ideas did Schwann and Schleiden

contribute to biology?

Anton Van Leewenhoek

• Observed pond water and saw living organisms underneath a microscope

• Father of Microbiology

Historical Video

• What did Robert Hooke do for biology?– Studied cork (oak bark) and observed tiny

compartments– First person to use the word “cell”

Historical Video

• Why are cells called cells?– Named after the tiny rooms that are found in

monasteries

Historical Video

• What ideas did Schwann and Schleiden contribute to biology?– Said that all organisms are made up of cells– Cells are alive and are the basic building blocks of

life– Organisms can be unicellular or multi-cellular

Cell Theory

• A theory is a well-tested hypothesis that can explain a broad range of observations

• Applies to all living organisms – big and small• One of the biggest foundational

understandings in biology

Cell Theory

1. All organisms are made of one or more cells.2. The cell is the most basic unit of life.3. All cells come from preexisting cells.

R.A.F.T.

• A creative writing assignment used to demonstrate understanding of concepts– Role: A scientist– Audience: A friend– Format: Written in the form of a postcard/letter– Topic: You’ve just observed living cells for the first

time. Describe the cells by using the Cell Theory. Discuss how this is completely different from the idea of the four humors and how microscopes helped advance biology.