Early Ideas
Spontaneous generation is the idea that living things come from nonliving things.
The experiment by Francesco Redi was performed in order to disprove or prove spontaneous generation. He wanted to see if fly babies (maggots) came from meat. He obtained three containers and put a piece of meat in each jar. One jar was left completely uncovered, one jar was covered with a porous material with small holes throughout it's surface, the other jar was completely covered with a top. After a while he checked the jars he realized the only jar with maggots in it was the jar left uncovered. He concluded that maggots did not, in fact, come from meat.
The experiment by Francesco Redi was performed in order to disprove or prove spontaneous generation. He wanted to see if fly babies (maggots) came from meat. He obtained three containers and put a piece of meat in each jar. One jar was left completely uncovered, one jar was covered with a porous material with small holes throughout it's surface, the other jar was completely covered with a top. After a while he checked the jars he realized the only jar with maggots in it was the jar left uncovered. He concluded that maggots did not, in fact, come from meat.
The experiment by Louis Pasteur was performed in order to disprove spontaneous generation. He used a long neck flask and filled it with rich broth. He boiled the broth to remove all impurities and let it sit. Because of the shape of the neck of the flask, dust particles and microorganisms never reached the broth to be able to inhabit it. If he tipped the flask to allow things to enter it, the microorganisms would be able to inhabit it. After this experiment, he concluded that microorganisms did not come from broth; therefore disproving spontaneous generation.
Biogenesis is the idea that living matter can only be derived from other living matter.
Modern Ideas
Scientists hypothesize that two things happened before life could appear on Earth. The first is that there had to be organic molecules-molecules containing carbon. The second is that the organic molecules must have formed into more complex molecules such as proteins, carbohydrates, and nucleic acids. These are the materials that are absolutely necessary for life.
The experiment by Miller and Urey was performed in order to simulate how the first life forms on earth came to be. They boiled water, exposed that water to the gases found in early Earth's atmosphere, and electrocuted the water. They wanted to see the carbon compounds formed in the early Earth's environment.
The experiment by Miller and Urey was performed in order to simulate how the first life forms on earth came to be. They boiled water, exposed that water to the gases found in early Earth's atmosphere, and electrocuted the water. They wanted to see the carbon compounds formed in the early Earth's environment.
The Evolution of Cells
The earliest organisms on earth were micro-fossils of prokaryotes that resemble bacteria found in archaic rocks.
They changed the atmosphere by producing oxygen which formed the ozone layer and increased oxygen concentration.
The Embosymbiotic Theory explains the relationship between prokaryotes being engulfed eubacteria and becoming what we refer to today as "organelles".
They changed the atmosphere by producing oxygen which formed the ozone layer and increased oxygen concentration.
The Embosymbiotic Theory explains the relationship between prokaryotes being engulfed eubacteria and becoming what we refer to today as "organelles".