What is LIFE??

Living Non-Living?

Organize the following into your table.. Toenail Sun Hair Nerve Cell Leaf Fire Tree bark Water Algae Bacteria

What makes something alive? Ideas?

7 Characteristics of Living Organisms Feeding Movement Breathing/ Respiration Excretion Growth Sensitivity Reproduction

Biology song http://www.youtube.com/watch?v=aynclw6TXeE

Where does it come from…?

The Big Question: ???????? Can Living things come from Non-living things??

What is Spontaneous Generation? The idea that organisms originate directly from non living matter “life from nonlife” ABIOGENESIS: the theory that states that non-living things can be transformed into living things. abiogenesis (a=not, bio= life, genesis= origin) It was common knowledge that simple organisms could come from dust, mud and food left out.

How Did This Happen? Every year the Nile River flooded leaving behind nutrient rich soil that enables people to grow that year’s crops. However, along with the muddy soil, large numbers of frogs appeared that weren’t around in drier times. Aristotle: Greek philosopher (384-322 BC)

How Did This Happen? Conclusion: It was perfectly obvious to the people back then that muddy soil gave rise to the frogs.

How Did This Happen? In many parts of Europe, medieval farmers stored grain in barns with thatched roofs. As a roof aged it started to leak. This could lead to spoiled or moldy grain, and of course, there were lots of mice around.

How Did This Happen? Conclusion: It was obvious that the mice came from the moldy grain.

van Helmont Even 300 years ago, a Belgian doctor, van Helmont concluded that mice could be created from grains of wheat and a dirty shirt.

What was wrong with van Helmont’s experiment? Wrong: open mouthed jar….things can get in

Hello, Francesco Redi Italian Doctor most well-known for his experiment in 1668 which is regarded as a one of the first steps in refuting spontaneous generation.

Up to this point, science was based on observation and analysis…now, experiments were needed to test the hypothesis… In 1668, An Italian physician, Dr. Redi, conducted an experiment to prove that flies did not come from rotting meat. Very controversial at the time…

What was the experimental variable? What was the controlled variable? What was the “active ingredient” that people believed was needed for spontaneous generation? Controlled = access to the jar active ingredient= flies Experimental = things grow?

The debate rages on…100 years later In 1748, John Needham performed an experiment similar to Redi’s except that he wanted to study the spontaneous generation of microorganisms instead of maggots. His experiment used 2 meat infusions which were both boiled to kill the microorganisms , then one was left open, the other was sealed with a cork. Micro-organisms grew in both flasks. Needham saw it as proof of spontaneous generation…. What do you think? What was the problem with this experiment? Problems: didn’t test water after boiling for microorganisms Could have gotten in through Cork Only work if ALL microorganisms were killed (they could multiply from just one).  Would have to test every drop of water to be sure ALL were killed and in doing so the jar may be contaminated.

Lazzaro Spallanzani Lazzaro Spallanzani was an Italian naturalist who also attempted to disprove the Theory of Spontaneous Generation, almost one hundred years after Francesco Redi. With the invention of microscopes after Redi's death, scientists were able to see tiny organisms that they could not see with the naked eye. In the late 1700's, Lazzaro Spallanzani tried to disprove this by performing a controlled experiment with broth.

Spallanzani…trying to disprove Needham Still only looking at one variable = closed vs open but what about boiled vs unboiled

Louis Pasteur Louis Pasteur was a French chemist who finally disproved the Theory of Spontaneous Generation in the mid 1800's. Louis Pasteur performed the same type of experiment as Spallanzani, except both of his flasks allowed air to enter

And so, 2000 years after it started the debate of abiogenesis vs And so, 2000 years after it started the debate of abiogenesis vs. biogenesis is settled: Life comes from life, not from spontaneous generation of non-living things!!!

Biogenesis Biogenesis is the process of life forms producing other life forms

(spontaneous generation doesn’t exist!!) LIVING LIVING LIVING NON - LIVING NON-LIVING LIVING (spontaneous generation doesn’t exist!!)

Passport: In Your Own Words What is the difference between Abiogenesis and Biogenesis? Take a minute to write out the contributions of each scientist and how each affected the Abiogenesis vs. Biogenesis debate.