1600s scientists observed cells• Most did not understand what they saw

1838 – cell theory• All things are made up of tiny units of matter

called cells• These cells divide and multiply• They cause organisms to grow

and mature• Developed by Mathias Schleiden

and Theodor Schwann

Cell theory failed to explain plants and animal varieties

1800s theory of evolution was proposed

Jean-Baptiste de Lamarck found similarities in fossils and living organisms

Charles Darwin built on Lamarck’s idea•Evolution based on natural selection

Gregor Mendel•Experimented with pea plants

•Trying to understand how characteristics passed between generations

•He discovered a gene Founded the study of Genetics

Fighting Diseases• 1796 Edward Jenner developed smallpox

vaccine• Louis Pasteur recognized the impact of

bacteria causing disease Showed bacteria could be killed

New Approaches to Surgery• Sir James Simpson discovered chloroform• Joseph Lister introduced methods to sterilize

instruments

Atomic theory – all matter is made up of atoms• John Dalton provided proof

Wilhelm K. Roentgen discovered X rays

Marie Curie and Pierre Curie discovered radium

Max Planck theorized that energy is released in units called quanta

People started using scientific method to study human behavior• Auguste Comte believed there was a set of laws

to human behavior• Father of sociology

Sociology – study of human behavior in groups

Psychology – study of human behavior in individuals

Ivan Pavlov – noted that human actions are unconscious

Sigmund Freud – father of psychoanalysis