In 1668, the Italian Doctor Francesco Redi demonstrated that the larvae found in rotting meat Came from fly eggs.
“Life only comes from a Pre- existing form of life”
In the second half of the 19th century, the French chemist Louis Pasteur demonstrated that Microorganisms did not come from spontaneous generation.
He placed soup in a flask, Bent the neck and sterilized it with heat.
After a number of weeks, The soup did not decompose.
He cut the neck of the Flask.
After a few days, he Observed that the soup in this flask had decomposed.
The S-shaped neck let air Into the flask, but not microorganisms. When the neck was broken, Microorganisms could enter and cause decomposition.
How living things change the Environment
-Plant Roots, lichens and the action of some animals (earthworms) break up rocks and Turn the soil. This makes it easier for erosion to occur and makes soil more Fertile.
-Some Sedimentary rocks are formed from layers of microorganisms (Foraminifera).
-The Accumulation of large number of coral skeletons can create islands.
-Trees Increase the humidity of an area because they stop the sunlight reaching the Ground.
-The Evaporation of water from the leaves of plants creates a humid microclimate. Some Plants have deep roots and can live near sand.Those Roots help hold the soil and prevent erosion (dunes).
-Human Beings modify the environment in the most obvious ways:
-Large buildings, roads, airports, ports..., Contamination And air pollution, Agriculture, Forest fires