(Level 2 Unit 4 Lesson 2) Exercise 3: Scanning
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Scan through the text for the following words. Click once on the first occurrence of the word
in the text.
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Energy flows from the sun to
the plants to the plant eaters to the meat
eaters.
Green plants and certain types of bacteria and
algae are the primary producers because they are
the ones that produce usable energy for the rest
of the living organisms on earth. They use
energy from the sun to make sucrose,
glucose,
and other compounds that other life forms can
eat and "burn" for energy. In each one of those
sugar molecules a little bit of the sun's energy
is stored in a form that we can call chemical
energy. But it might better be called "potential
energy" since it is a sort of
"doing-nothing-for-now-waiting-to-happen" kind
of energy.
Herbivores are the plant eaters. They have the
ability to
digest
the plants they eat and
release the energy stored in the plant cells for
their own use. Some examples of animals in this
group are deer, cows, elephants, rabbits, elks,
zebras, most insects, and birds that eat fruit
and seeds. Sometimes scientists call this level
of the food chain the Primary
Consumers.
These are the meat eaters.
Predators and
scavengers
are in this group. Sometimes this
level in the food chain is referred to as the
Secondary Consumers. They eat the animals that
eat the plants and sometimes they eat each
other. Most of these animals can't eat plants at
all. They would
starve to death if it weren't
for the Herbivores digesting the plants first.
They've got the top job but they're really quite
helpless without all the boring plants and
herbivores. Cats and dogs, killer whales,
sharks, spiders, snakes, wolves, vultures,
hawks, eagles, crocodiles, and many other
fierce
predators that for some reason we are especially
fascinated
with, are in this group.
They are the organisms that eat up dead bodies,
both plant and animal. And aren't we happy they
do. This group of useful creatures are mostly
bacteria and
fungus, but also, according to our
sources, includes
maggots,
dung beetles, earth
worms and many other eaters of dead organic
matter. Without them there would be a lot of
dead bodies lying around. They're like
carnivores and herbivores, because they also
have to get their energy from the cells of
animals or plants. The difference is they prefer
their food dead - very dead.
What do you think? Are maggots decomposers or
carnivores (or just horrible little things we'd
rather not think about)?
Omnivores are the last type and eat both plants
(acting a primary consumers) and meat (acting as
secondary or tertiary consumers). Examples of
omnivores are:
Bears: They eat insects, fish, moose, elk, deer,
sheep as well as honey, grass, and leaves.
Turtles: They eat snails, crayfish, crickets,
earthworms, but also lettuce, small plants, and
algae.
Monkeys: They eat frogs and lizards as well as
fruits, flowers, and leaves.
Squirrels: They eat insects, butterflies, bird
eggs and nesting birds and also seeds, fruits
and nuts.
Some animals can eat plants and other animals.
So you could say they are both a herbivore and a
carnivore. That's the way humans are. We can eat
plants and we can eat meat. It must have been
too difficult for biologists to say
herbicarnivore or carniherbivore (don’t try to
find these words in your dictionary), so they
decided to call humans, and others like us,
omnivores. It means we'll eat just about
anything we can get our hands on. I can't think
of anything better than being an omnivore. We
can be either primary or secondary consumers. It
makes shopping so easy!
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