1600’s Spontaneous Generation Rules

1. 1600’s Spontaneous Generation Rules The idea that organisms originate directly from nonliving matter. "life from nonlife"

2. 1620 James Ussher Using Biblical chronology and writings of the early Christian church fathers, Bishop Ussher comes to the conclusion of a young earth. Less than 6000 years old. The church is still highly regarded even though it has lost much of it power. Faith, not naturalism, still held onto by commoners.

3. Old Belief a seventeenth century recipe for the spontaneous production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice. Although such a concept may seem laughable today, it is consistent with the other widely held cultural and religious beliefs of the time.

4. Old Belief • 1664 Christian Huygens and his wife are lens makers. Together they perfect the art and science of lens making. Glass is clearer without any bubbles or aberrations due to warping. • As a results Van Leuwenhook , also a lense maker creates a compound microscope that he uses to look at small “animalcules”. He is the first to begin to disprove Spontaneous generation. • Robert Hooke discovers “cells”.

5. 1668 Redi tries to disprove spontaneous generation Francesco Redi - One of the first to disprove spontaneous generation

6. In your journal describe the Redi experiment and tell how it disproved spontaneous generation. In your explanation, include; • What variables had to stay constant? • Which variable was the independent variable? • Which was the dependent variable?

7. Redi's Problem Where do maggots come from? Hypothesis: Maggots come from flies. Redi put meat into three separate jars. Jar 1 was left open Jar 2 was covered with netting Jar 3 was sealed from the outside

8. Redi's Experiment Step 1 Jar-1 Left open Maggots developed Flies were observed laying eggs on the meat in the open jar

9. Redi's Experiment Step 2 Jar-2 Covered with netting Maggots appeared on the netting Flies were observed laying eggs on the netting

10. Redi's Experiment Step 3 Jar-3 Sealed No maggots developed

11. Collect and catalog types of fish and birds based on their structures. • Through their studies, they prove that fish and birds are a product of sexual reproduction and not spontaneous generation. • But , wait a minute… Francis Willoughby & John Ray 1677

12. What about plants? Surely plants are a product of spontaneous generation. • The then famous Joseph Pitton De Tournefort who refused to use a microscope and divided plants by their structure not caring or daring to entertain what the parts were for. Tournafort believed in, wrote, and taught spontaneous generations of plants. • Enter Sebastian Sébastien Vaillant. With help from John Ray these two identified the sexual reproductive organs of the flowering plant and proved that plants do not spontaneously generate. • Case closed? Francis Willoughby & John Ray 1677

13. It would seem that after 1708, spontaneous generation for larger animals and plants seems to have been proven incorrect. But Remember that little invention back in the 1590’s? Well it has helped naturalists (scientists) to discover little animalcules later known as microorganisms, and they are everywhere! Water, dirt, food, in the air we breathe OUR AIR!!!

14. Still not convinced! The debate over spontaneous generation continued for centuries .The year is now 1745, John Needham, an English clergyman, proposed what he considered the definitive experiment. Everyone knew that boiling killed microorganisms, so he proposed to test whether or not microorganisms appeared spontaneously after boiling. He boiled chicken broth, put it into a flask, sealed it, and waited - sure enough, microorganisms grew. Needham claimed victory for spontaneous generationfor microorganisms.

15. Try Again! • 1768 An Italian priest, Lazzaro Spallanzani, was not convinced, and he suggested that perhaps the microorganisms had entered the broth from the air after the broth was boiled, but before it was sealed. To test his theory, he modified Needham's experiment - he placed the chicken broth in a flask, sealed the flask, drew off the air to create a partial vacuum, then boiled the broth. No microorganisms grew. Proponents of spontaneous generation argued that Spallanzani had only proven that spontaneous generation could not occur without air. • ARRRRG!

16. Pasteur to the Rescue! Spontaneous Generation

17. The theory of spontaneous generation was finally laid to rest in 1859 by the young French chemist, Louis Pasteur. The French Academy of Sciences sponsored a contest for the best experiment either proving or disproving spontaneous generation. Pasteur's winning experiment was a variation of the methods of Needham and Spallanzani. He boiled meat broth in a flask, heated the neck of the flask in a flame until it became pliable, and bent it into the shape of an S. Air could enter the flask, but airborne microorganisms could not - they would settle by gravity in the neck. As Pasteur had expected, no microorganisms grew. When Pasteur tilted the flask so that the broth reached the lowest point in the neck, where any airborne particles would have settled, the broth rapidly became cloudy with life. Pasteur had both refuted the theory of spontaneous generation and convincingly demonstrated that microorganisms are everywhere - even in the air.

19. The germ theory was the foundation of numerous applications, such as the large scale brewing of beer, wine-making, pasteurization, and antiseptic operations. Another significant discovery facilitated by the germ theory was the nature of contagious diseases. Pasteur's intuited that if germs were the cause of fermentation, they could just as well be the cause of contagious diseases. This proved to be true for many diseases such as potato blight, silkworm diseases, and anthrax. After studying the characteristics of germs and viruses that caused diseases, he and others found that laboratory manipulations of the infectious agents can be used to immunize people and animals. The discovery that the rabies virus had a lag-time before inducing disease prompted the studies of post-infection treatment with weakened viruses. This treatment proved to work and has saved countless lives.

20. It took from 1600 to 1859 (almost 250 years) to prove that; Life comes from life. 1. All living things are made of cells. 2.Cells are the basic unit of all life. 3. Cells come from other living cells. These are the three principles of cell theory.

21. Miller- Urey experiment 1952 What is the difference between abiogenesis and spontaneous generation?