The Web of Life

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The Web of Life

• 5.9BFood Webs

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The Web of Life

• Describe how the flow of energy derived from the
  sun, used by producers to create their own food,
  is transferred through a food chain and food web
  to consumers and decomposers.

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The Web of Life

• I am a spider. Just your average,
  run-of-the-mill, garden spider. You may have seen
  me 'hanging' around. I am going to explain the
  web of life to you because, you see, I am an
  expert on webs. Lets see, where shall I start?
  Uhmm, yes, Ill start by doing what I do best
  weaving the web!

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The Web of Life

• You see, there are all sorts of creatures in the
  wild, and they each play a role in the web of
  life. There are lots of different kinds, or
  species, of plants and animals. They come in
  different sizes, shapes and colors. They live in
  different places and behave in very different
  ways.

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The Web of Life

• But for all their differences, plants and animals
  need a lot of the same things to survive. In
  fact, they need each other. Thats what the web
  of life is all about! Let me start at the very
  beginning with my very own web.

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The Web of Life

• You see, as a garden spider, I meet lots of
  plants and animals. Some of them are my friends,
  some of them are not so friendly, and some of
  them are my dinner!
• Since I am, after all, a garden spider, let me
  show you around my garden. The plants you see
  here are my friends. Plants are friends to
  everyone in the web of life. To tell you the
  truth, none of us could live without them! But
  dont tell them that - they might get swelled
  heads over it. Oh, I guess you have a point.
  Plants dont have heads, do they?

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The Web of Life

• So, there are millions of different kinds of
  plants all over the world! Plants are really
  quite simple. All they really need is sunlight
  and water!
• Plants may not seem very interesting. I mean,
  they cant talk to you, right? So why am I
  friends with them? Well, believe me, none of the
  animals youre about to meet would be around
  without plants, so we should all appreciate them!
  

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The Web of Life

• Plants are VERY important producers. They
  produce food for many other organisms!. Let me
  introduce you to some animals that eat plants!
• Lots of animals eat plants. Animals that eat only
  plants or plant parts are called herbivores.
• As a matter of fact, a whole lot of animals are
  herbivores. Let's see, how many animals can you
  name that eat plants? Here, let me help you.

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The Web of Life

• Now be very, very quiet. That guy over there,
  he's a bird. Some birds eat seeds, which come
  from plants!
• Some birds also eat wonderful little spiders like
  me, so don't let him see me! Quick, let's get out
  of here!

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The Web of Life

• Whew, that was close!!!
• Let's go talk to a squirrel. They don't eat
  spiders. They eat nuts (which also come from
  plants).
• I bet his friend over there is hiding nuts for
  the winter!

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The Web of Life

• Squirrels eat nuts, and they also bury them for
  storage to eat in the winter time. The ones they
  forget about will grow up to be trees and make
  more nuts!
• Squirrels and trees are very good friends.

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The Web of Life

• Oh dear, here comes a deer!
• Deer eat the leaves of plants. They don't bother
  me except when they walk through a spider web
  I've worked so hard to build.

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The Web of Life

• I better get back to work here, still talking
  about plants. You see, plants aren't just a
  source of food. For many animals, they're home!
• How can an animal live in a plant you ask? Just
  look at me! I build my spider webs between
  branches of trees or blades of grass. Other
  animals use grass to hide in, like baby deer
  (fawns). Other animals, like mice, use grass to
  build homes.

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The Web of Life

• Trees are homes for many animals. All kinds of
  birds, insects and squirrels can call a tree
  home. For large animals like bears and wolves,
  the whole forest is their home. It's what
  scientists call "habitat."

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The Web of Life

• I would introduce you to habitat, except habitat
  isn't a plant or an animal - it's a whole
  community of plants and animals! It's a lot like
  the town or city in which you live. It's where
  animals get the food they eat and the water they
  drink - it's just plain where they call home.
  Habitat is just as important to animals as
  animals are to each other.

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The Web of Life

• Now, let's get back to the story. Remind me
  again, where was I?
• Oh my! Now I remember! I completely forgot to
  tell you about bugs! Why, bugs are my favorite
  animals! I eat them! That makes me a carnivore,
  because I only eat meat!
• There are many kinds of bugs. And there are
  different bugs in different places. What kinds
  of bugs live near you?
• Have you seen any ants? How about crickets? Mmm .
  . . I love crickets. Where did you see them? I'll
  have to come visit you!

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The Web of Life

• Bugs do a lot of different things. Bees visit the
  flowers of plants and take nectar and use it to
  make honey. While the bee is collecting nectar,
  it usually gets a powder on it called pollen.
  This is sort of like when you walk in the woods
  and seeds get stuck to your pants. Bees fly from
  one flower to the next, carrying this pollen.
  Some of the pollen falls off into the flowers,
  and the plants use that to reproduce! The plant
  is helping the bees, and the bees are helping the
  plants! That works out pretty well, don't you
  think?

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The Web of Life

• Some bugs eat plants. Now I'm sure you've seen
  caterpillars before! Caterpillars eat lots and
  lots of leaves before they grow up and turn into
  moths or butterflies. But not every caterpillar
  grows up. Why not?

Because birds eat them! Some birds are
herbivores while other birds are carnivores. I'd
introduce you to a caterpillar, but you see, I
ate the last one I met. Well, don't look at me
like that, I was hungry!
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The Web of Life

• Now that I'm full, I guess we can stop talking
  about what I eat and go meet some other animals.
• Follow me! Ah! Allow me to introduce you to Red,
  the fox, and Wiley, the coyote. Now gentlemen,
  would you describe each other as friends?
• "GRRR!"
• Oh my! Clearly not!

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The Web of Life

• Perhaps I can shed some light on the situation.
• You see, most animals eat lots of different
  things. Some animals are predators, which means
  they hunt and eat other animals. The animals they
  eat are called prey. And then there are some
  animals that scavenge for food. Scavengers eat
  other animals too, but, unlike predators, they
  don't do the hunting. They eat what other
  predators have killed or animals that have died
  of natural causes. Sometimes a hungry predator
  will scavenge for food when there's nothing else
  to eat.
• What does all that have to do with Red, the fox
  and Wiley, the coyote?
• Plenty, believe me!

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The Web of Life

• You see, even though Red the fox is a carnivore
  and a predator of rabbits and mice, sometimes the
  fox is the prey of the coyote! Keep that in mind,
  because the web of life is about to get very
  twisted - so hold on!
• The fox and the coyote are also competitors! Why?
  Because animals usually eat more than just one
  thing - they have to in order to survive!
• When two animals eat the same food, they're
  called competitors, because they are competing
  for a limited amount of the same food. Get it?
• You see, the fox and the coyote compete to eat
  mice and rabbits.

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The Web of Life

• I bet you're thinking that as a top predator, the
  carnivorous wolf is at the top of the food chain,
  right? Well, not exactly. You see, describing the
  web of life as a food chain isn't very accurate.
  . .

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The Web of Life

• Let me just climb up onto this wolf. Huh, huh, oh
  my, this is a long climb for me. There, made it!
  So here I am, standing in the fur on the back of
  a wolf. I don't usually do this sort of thing,
  but for you, I've made an exception.

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The Web of Life

• Let's see who we can meet up here.
• Hey, look! It's a family reunion! This is my
  distant cousin, the tick! Ticks feed off of the
  blood of other animals. You may have met one
  before, perhaps on your dog. They are called
  parasites.
• Mosquitoes and fleas - those wacky bugs - also
  feed off the blood of animals. I'm sure you've
  met a few of them in your time!

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The Web of Life

• So you see, even predators and carnivores are
  food for other animals. That's why there really
  isn't a "top" to a food chain or a food web.

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The Web of Life

• Even predators die sooner or later. Sometimes
  they die from old age or from injury. Other times
  they die when there's not enough food around.

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The Web of Life

• When a predator or its prey dies, some of it is
  usually eaten by scavengers. What they don't eat,
  bugs will eat, and so its body is broken down.
  What's left over eventually becomes part of the
  soil - providing nutrients to the soil and food
  for - you guessed it - plants!  

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The Web of Life
Carnivores (Tertiary Consumers)
Carnivores (Secondary Consumers)
Herbivores (Primary Consumers)
Producers
Decomposers
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The Web of Life

• So you see, in the web of life, every animal and
  every plant relies on other plants and animals to
  survive. The web of life isn't a chain, and it's
  not quite a circle. It's an important connection
  between all life, and no one part of it is more
  important than another. All animals and plants in
  a sense work together to survive.

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The Web of Life

• That's why preserving habitats and protecting
  endangered species is very important! So make
  sure you do your part.
• Be a Defender of Wildlife!