Cells

Is fire a living thing?

Robert Hooke

• Observed cork under a microscope• Called the little boxes cells

Anton van Leeuwenhoek

• Examined blood, rain water, teeth scrapings• Found tiny animal-like things• Led to better microscopes

Other Scientists

• The discoveries of Hooke and van Leeuwenhoek led to better tools and other discoveries about cells.

M. Schleiden T. Schwann R. Virchow(Botanist) (Zoologist) (Pathologist)

Cell Theory

• All living thing are made of cells• Cells carry out the functions needed to

support life• Cells come from other living cells

Scientific Theory – widely accepted explanation of things in nature. It must be supported by evidence.

Louis Pasteur

• Noticed milk that soured contained many bacteria

• He invented a process that killed the bacteria and allowed the milk to last longer

• He wondered if bacteria were responsible for the illnesses in people and animals.

Louis Pasteur

• He noticed by studying air, water and soil that bacteria were everywhere (germs)

• He realized that by understanding germs we could prevent disease• His work led to vaccines

Spontaneous Generation

• Life could come from nonliving things

• Pasteur showed in a series of experiments that spontaneous generation can not occur

• He supported cell theory

Redi’s Experiment

• Shows that the presence of maggots was not spontaneous but a result of fly offspring

Pasteur’s Experiment

• Showed that bacteria was in the air and did not spontaneously generate.