Name: __________________________________
Cell Theory
Directions – Highlight the most important information within each paragraph and answer the questions in
schoology.
Spontaneous Generation
Although scientists continued their search for all things small, there was a 200 year gap in major discoveries.
Scientists didn’t stop looking. Instead, it was a strange belief that kept them from moving forward. Before the
mid 1800s, people believed that all organisms appeared out of nowhere, kind of like magic.
For example, there was a strong belief that mice, those little furry rodents, came from corn husks and dirty
clothes because they always seem to be in them. Your parents might have told you that babies were delivered
by a stork, but hopefully you now realize that’s not true. People also believed that maggots, the little worms
that you might see in rotting meet, actually appeared magically from the rotting meat.
This belief in things appearing out of nowhere had been around for thousands of years
and was called spontaneous generation.
In the mid 1800s a famous scientist named Louis Pasteur (the same guy that
pasteurized milk) set out to disprove this theory. It didn’t take long for him to find out
that mice actually come from other mice and that maggots are the hatching eggs laid
by house flies (yuck ).
1. What is spontaneous generation?
a. The idea that cells come from other cells.
b. The idea that living things appear out of nowhere.
c. The idea living things are living in pond water.
d. The idea that living things evolved from a common ancestor.
The Cell Theory
Free of the silly belief that magic created cells, scientists finally declared that cells are
present in all living things. In 1838, one scientist, Matthias Schleiden, discovered that all
plants were made of cells. Then in 1839 a close friend of Schleiden, Theodor Schwann,
declared that all animals were made of cells.
Now, they didn’t just say this without doing lots of work.
These two scientists along with many other scientists looked
at lots different types of animals and plants. It was only in the
end that these two put it all together.
Soon after both discoveries, Schwann put the first two parts of The Cell Theory into
writing:
All organisms are made of one or more cells.
The cell is the basic unit of all living things.
