What is Food?

Sounds like a Simple question!

Right?

We all know what food is!

Food is what we eat for breakfast, lunch and dinner.

BUT,

To understand how living things get their food, you need to know the scientific definition for the word food.

People have many ways of thinking

about what food is.

Some people say juice is not

food because we don’t

chew it.

Scientists experimented and found out that the things we take into our bodies do different things.

Water does not do the same thing for your body that meat or sugar do.

For example…

Scientific Definition

d. Food is

matter(building materials) that contain energy that living things can use to live and grow.

All living things use

the energy and matter in food to grow and to keep all their parts working properly.

Matter is the stuff (materials) that things are made of. Scientists usually define

matter as anything

that takes up space and has

mass. Matter provides the physical building blocks that living things use to grow (become bigger).

Energy is what

makes all your cells and bodyparts work. It gives your body the power to breathe, to move blood, to move muscles, to repair cuts, to think, and all the other things your body does.

Livings things need both matter and energy.

How can we find out what materials are

food?

Living things get all of their energy from food.Without food, they have no energy to continue living.

Energy in food is measured

in calories.

Foods with lots of calories have lots of energy stored in them.

We can tell whether materials are foodBy looking to see if they contain

calories.

What’s the matter with you?

Seriously!

Food also has matter. Without food, living things have no building materials to grow and take care of all the things necessary to survive.

We can tell whether materials have

matter by looking to see if they have mass.

Mass is

measured in

grams (g).

Are these materials food?

sugar

Orange juice

watervitamins

Plant food-fertilizers

Remember if it’s food then it must have …

Calories=energy

Matter/mass=grams

Why does this all matter?

Well, all living things are connected to one another in what scientists call food webs. Each organism in a food web has a specific purpose related to food!

Living things depend on one

another to get the food

energy they need to live and grow.

In every food web, there are three main types of organisms:Producers Consumers Decomposers

And then there was

light!

Producers make their own food using energy from the sun.

Consumers get their food energy from other organisms.

Decomposers get their food energy by eating once-living things.

Most producers are green like grass, trees, shrubs, and vines. Producers are important because they are the only organisms that can use energy from the sun to make

their own food energy.

Plants get their food through a process called

photosynthesis.

photo+synthesisPhoto = Light

Synthesis = Putting Together

How does photosynthesis work?

Energy enters most ecosystems and food webs as light from the sun. However, living things cannot use sunlight directly to get energy to live and grow.

Basic photosynthesis…

Light from the sun has to be converted into chemical energy stored in food molecules…

Sun

photosynthesis at work…

Sun

Light Energy

The plant uses the energy in sunlight to buildhigh-energy sugar molecules out of low-energymolecules.

photosynthesis

Sun

Light Energy

Carbon Dioxide

Water

The low-energy molecules are water and carbon dioxide.

photosynthesis

Sun

Light EnergyCarbon Dioxide

Water

Sugars

The high-energy bonds within sugar, when broken, release usable energy for the plant to live and grow.

photosynthesis

Sun

Light EnergyCarbon Dioxide

Water

Sugars

Sugars stored within the plant are also the energy source/food for animals that eat the plant.

photosynthesis

Sun

Light Energy

Sugars

The plant needs the sugars for its own source of energy to live. The sugars are made in the leaves through photosynthesis and then move throughout the plant to give energy to every cell in the plant.

photosynthesis

Sun

Light Energy

Oxygen

Oxygen is released from the plant as non-energy supplying matter.

Put it all together…

Basic Photosynthesis Sun

Light EnergyCarbon Dioxide

Water

Sugars

Oxygen

Food and energy chains begin with producers, which convert the energy in sunlight into chemical energy in food.

What’s next in the food

chain?

?

Consumers

Consumers get food energy by eating other organisms.

Types of consumers…

Herbivores are consumers that

get food energy by eating plants.

Carnivores are consumers that

get food energy by eating only other animals.

Omnivores are consumers that get foodenergy by eating both plants and animals.

What’s next in the food

chain?

?

Decomposers

Decomposers are a special category that

gets food by feeding on dead and decaying things.

Decomposers break down matter from dead producers and consumers into smaller and smaller particles that are released into the environment as air, water, and soil.

These particles, called nutrients, can be used again by plants for matter, but not for energy.

Common decomposers include…

worms

mushrooms

mold

So we have a simple food

chain?

Food chains can interlink making a food web…

Hognose SnakeHawk

Garter SnakeToad

Rabbit

Grasshopper

Grass

Spider

Mouse

Praying Mantis

Sparrow

Confused? For now remember…

All living things are connected to one another and has a specific purpose…

You guessed it…

FOOD

CreditsSlide Number 2: Steven Depolo, “Qiqi Sandmann’s Ribs” April 17, 2011 viaFlickr, Creative Commons Attribution.

Slide Number 7: Pacific Northwest National Laboratory, “Food Services and ProcessMeasurement Laboratory” June 17, 2009 via Flickr, Creative Commons Attribution.

Slide Number 12 and 44: Barbara Blmiers, “Nature-Animal-Wildfire-White-tailed-Deer”October 16, 2011 via Flickr, Creative Commons Attribution.

Slide Number 17: Brandon Baunach, “Crying Baby” August 8, 2007 via Flickr, Creative Commons Attribution.

Slide Number 22: Loiez Deniel, “Cat vs. Fish” September 4, 2009 via Flickr, Creative Commons Attribution.

Slide Number 28, 48, 49, and 53: Ryan Steele, “Mushrooms” August 15, 2004 via Flickr, Creative Commons Attribution.

All other images were created using an IPhone.