Natural and Artificial Food:Slide Show

Main topics: a natural process: photosynthesisan artificial process: agriculture

Part One: What is Food?

All living organisms use energy. 

This includes YOU!  Your body has stored energy, which you burn up all

day.

      But why don't you run out of energy?Where does more energy come from?

Your energy comes from FOOD, of course!  But what is food?

Food is other organisms.  Their bodies also have stored energy, so

when you eat them you take their energy.

This is true whether we eat the organisms

whole...

or in processed form.

OK, but where do those other organisms get their energy?

The animals eat plants, and other animals.

But where do plants get their food?

Plants make sugars, by combining• water, from the soil• carbon dioxide, from the air• light, from the sun

This is photosynthesis, which means to create ("synthesize") using light ("photo").

The plants created their own food,

inside their bodies.

All food started with photosynthesis.Even when we eat other animals, we are eating plant sugar-- indirectly.

You run on solar energy!

Part Two: Natural vs. Artificial Food

For millions of years, people got food by hunting and gathering.  

• Hunting means to kill wild animals.• Gathering means to collect wild

plants.

Hunting and gathering required great work and knowledge.  Wild animals are hard to catch, and edible plants are hard to find. So hunting and gathering could only feed a few people. Earth's human population was much smaller.

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About 10,000 years ago, various peoples started breeding plants and animals.

People wanted plants and animals thatgave them more food.  

This was the Agricultural Revolution.  

People started sowing (planting) plants. 

They kept the biggest and yummiest seeds.The next year, those seeds grew into plants

that also had big, delicious seeds.

By doing this over and

over,people in Mexico turned

teosinte grass into

corn.

People also started herding animals-- protecting and controlling them. 

People let big, fat, tame animals have babies, who would be yummy and tame

like their parents.  This is how people made tough, skinny boars into fat, friendly

pigs.

wild European boar Domesticated (tame) pig

These plants and animals were now partly artificial; humans had puposely reshaped them.  (This is what we call artifice or art.)

Natural things are wild; they do what they like.Artificial things are tame; they do what we like.

The opposite of artificial is natural, but even artificial things are partly natural.  For example, people didn't create corn's roots or leaves or seeds-- but they did make its seeds bigger.

Most people kept hunting and gathering, even after they started herding and planting.

But the change was very important, because herding and planting people tend to . . .

• guard crops and herds, so they live in one place• eat more food, so their population grows• have extra food, so they develop markets• develop cities, writing, and large governments

Here's the bottom line:

The world you know-- its cities, governments, markets, writing, and manufacturing-- exists because of agriculture.  Farmers make enough food so that everyone else can do other things.

Without agriculture, you would be outside right now, looking for something wild to eat. 

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