What is Life?. Think of an example of a living thing…. What is it? How do you know it is living?. Examine the items provided. Which one is living? Which is dead? Which is non-living? HOW CAN YOU TELL? What are the characteristics that allow you to make that conclusion? Class share.
Greek philosopher (384-322 BC)
1580 - 1644
1626 - 1697
1713 - 1781
In 1748, John Needham performed an experiment to study the spontaneous generation of microorganisms instead of maggots.
Micro-organisms grew in all flasks. He saw this as proof of spontaneous generation.
1729 - 1799
In 1768, Spallanzani performed an experiment to disprove Needham
Micro-organisms did not grow in the sealed flask. He felt this “disproved” abiogenesis.
1822 - 1895
In 1864, Louis Pasteur “definitively” disproves abiogenesis
The swan-necked flask developed by Pasteur enabled him to definitely disprove abiogenesis for micro-organisms by showing that these creatures arise in food from airborne spores.