spontaneous generation?

Question

could you help me while im studying?
what is spontaneuous generation? who were the key players in determining that spontaneuous generation does not happen? what did they do? Explain how scientists believed life began on earth. What organisms were first to develop. Who were Miller and Urey? What did they do? What role did oxygen play in the evolution of life?

Answer 1

Spontaneous generation was the concept that life regularly sprung from non-life ... even to the point where a recipe of dirty laundry and wheat could produce rats (I'm not exaggerating).

The key players in disproving the idea were Francesco Redi, Lazzaro Spallanzani, and Louis Pasteur (see first two sources). What they all did was to show that a sterilized and isolated environment would not produce life, even if left for weeks. This is known as the principle of abiogenesis.

However, this result has little bearing on the origins of life on earth. These were only disproving the idea that life would *regularly* spring from non-life. The experiments involved a couple of flasks, a handful of ingredients, and at most a couple of weeks of duration ... and thus would have no bearing at all on events that involved all the earth's oceans, all the complex ingredients and conditions of life on the early earth, and over a *billion* years (!) in duration.

There are many theories about how life first began on earth. Most are based on the idea that the early earth contained the raw ingredients for organic compounds (the building blocks for proteins), and with the right energy conditions and enough time, the basics of a replicating molecule arose, which was enough for natural selection to act, and evolution began.

The first organisms were most likely very primitive strands of RNA, that did little more than replicate using the abundant organic materials available. Over time this produced proteins, which are better catalysts for chemical reactions than RNA is (although not as good a replicator), and DNA, which is a better replicator, but not as good a catalyst. And so the trio DNA-RNA-proteins emerged as the basic system for life that we see today.

The Miller-Urey experiment was one of the first experiments to show conclusively that organic compounds could arise from inorganic ingredients given the right conditions and energy (resembling lightning). For more information, see the last source below.

Answer 2

Spontaneous generation is what was believed quite a while ago (until the late 19th century). It was thought that smaller life forms would spontaneously generate in mainly rotting meat. It was not understood that there were larvae forms of many organisms or that flies buzzing around could leave eggs that hatched a larvae form. Nor was it understood that there could be life forms too tiny to see.

Louis Pasteur was one of the first to realize that there were invisible germs and a lot of lives could be saved from infection if doctors would simply wash their hands when they went from on patient to the next.

I will let someone else answer all your other questions.

Answer 3

Funny how you just posted this question because I've got a test on it tomorrow.

Spontaneous generation is an early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc).

Louis Pastur disaproved spontaneous generation.

To the person above me: Joseph Lister is actually the one that first introduced the aspectic technique in order to reduce microbes in a medical setting and prevent wound infections by simply sterlizing everything and washing the hands.