Download Answers to Grade 7 - 1.2 and 1.3 in Student Book

1.2
The Roles of Producers (See Student Book pages 17–23)
How Producers Use the Sun’s Energy
Sunlight is an important abiotic element in most ecosystems. Sunlight enables
photosynthesis to take place. Photosynthesis is a chemical reaction that uses sunlight
to produce food for plants.
• Carbon dioxide from the air combines with water from the roots to make food
(a type of sugar) and oxygen.
• The food is stored in the plant, and the oxygen is released back into the air.
• Animals, including humans, use the oxygen that plants produce during
photosynthesis.
Write the labels below in the correct place on the diagram.
• Carbon dioxide from the air enters the leaf.
• Sunlight shines on the leaf and brings heat and light energy, causing a chemical
reaction.
• A sugar called glucose is produced.
• Oxygen is released from the leaf.
• Water and nutrients from the soil come to the leaf through the plant stem or trunk.
Sunlight shines on the
leaf and brings heat
Note: “photo” means light and
“synthesis” means to combine
things together. So,
“photosynthesis” means using
light to combine different
materials.
and light energy, causing
a chemical reaction.
A sugar called glucose
Carbon dioxide from the
is produced.
air enters the leaf.
Oxygen is released
Water and nutrients from
from the leaf.
the soil come to the leaf
through the plant stem
or trunk.
Photosynthesis occurs in the leaves of plants. It uses light energy from the Sun.
Key Term
photosynthesis: a chemical reaction that takes places in plant leaves and changes sunlight into food
for the plant
Producers’ Roles
Plants are considered producers. Producers can make their own food. This food
supplies the energy the plants need to survive. Producers have three main roles:
• they provide oxygen
• they provide a place to live
• they supply food
Note: Think about where your food
comes from. For example: french fries—
potatoes that grow on farms; pizza—flour
crust that comes from wheat grown on
farms; toppings are fruit, vegetables, and
meat—all from farms (not from
supermarkets!).
This garden is a place where living things can feed and live.
Circle the producers in the above illustration.
Most living things have to eat in order to get energy. Many living things eat only
plants. Others eat the living things that have eaten the plants. The producers are the
beginning of all food interactions.
Circle the homes you see in the illustration.
Plants provide homes for many animals.
A tree can die and become an abiotic part
of the system. Even then, it can still provide
a home for living things. In a pond, fish
shelter under the plants that grow there.
Interactions in Ecosystems
Interactions happen throughout ecosystems.
Plants take in energy from the Sun and water
and nutrients from the soil. Animals eat plants
Plants provide homes for animals.
and other animals, find shelter, and find water.
Interactions can be helpful or harmful to living things. When a bee buzzes from flower
to flower, the bee gets food and the flower is able to produce new seeds. When a spider
eats a fly, the fly dies, while the spider gets energy.
Key Term
producer: a plant or plant-like living thing that can make its own food to provide it with the energy it
needs to survive
Section 1.2
3
Populations and Communities
Biotic parts of communities are easier to study if you know the words you can use to
discuss them. The table shows the words used to describe different groups in an
ecosystem.
Term
Relationship to Ecosystem
Example
Species
Closely related group of living things. • Mallard duck in a pond
They can produce babies and their • Willow tree at the edge of
children can produce babies when
the pond
they become adults.
Population
A group of the same type of living
things living in the same place.
• All the ducks living near the
pond
• All the water lilies on the
surface of the pond
Community
All the different populations of
different species that live and
interact in a habitat.
• The duck, fish, all the
plants, the soil, rocks, and
water of a pond
Think of a wooded area or a park near where you live. What makes up the community
of living things that exist in that area?
Name four species in that area.
plants of various kinds, trees, raccoons, squirrels, birds, insects
Name four populations of living things in that area.
dandelions, maple trees, raccoons, squirrels, Canada geese, mosquitoes
Use the above living things to write three sentences that describe the community.
Be sure to include the abiotic factors as well in your description.
The following kinds of descriptions are possible: Insects breathe the air, live in the bark of trees, and
eat leaves. Birds breathe the air, live in nests, and eat small insects. Squirrels breathe the air, live in
hollows or nests in trees, and eat nuts.
Note: Have students transfer the information in the table to their notebooks using the first and third columns
and using drawings for the third column instead of words. Have them add one or two examples of their own
of species and population. This will help you assess their understanding of these concepts.
Section 1.2
4
1.2
Check and Reflect
1. Fill in the blanks with the correct words so that the paragraph describes how
plants work.
carbon dioxide
photosynthesis
oxygen
Sun
producers
food
Plants are
producers
because they can use energy from the
Sun
to
make their own food . During the process of photosynthesis they take
carbon dioxide
out of the air and they put oxygen back into the air.
2. Read the following statements about producers. If they are true, circle T; if they are
false, circle F.
(a) Producers supply oxygen.
T
F
(b) Producers destroy food.
T
F
(c) Producers supply minerals.
T
F
(d) Producers supply shelter.
T
F
3. Which of the following is not involved with the process of photosynthesis?
(a) sunlight
(b) habitat
(c) carbon dioxide
(d) sugar
4. Plants provide a number of necessary elements in an ecosystem. Which do they
not provide?
(a) shade
(b) heat
(c) oxygen
(d) shelter
5. Which living thing found around a pond is not a producer?
(a) lily plant
(b) willow trees
(c) pond snails
(d) reed sweet grass
6. Which statement about the role of producers in supporting life on Earth is true?
(a) Producers provide many things, but they do not provide shelter.
(b) Producers use oxygen in Earth’s atmosphere to produce carbon dioxide
and sugar.
(c) Producers are green because their leaves contain large amounts of oxygen.
(d) Producers are the only organisms that can use the Sun’s energy to make food.
1.2 Check and Reflect
5
1.3
Producers and Consumers (See Student Book pages 24–30)
Types of Consumers
All animals are consumers. Consumers are living things that cannot make their own
food. They must eat, or consume, other living things in order to survive. We describe
consumers by what they consume. Look at the table below to find three types of
consumers and the type of food each consumes.
Type of Consumer
Food Eaten
Examples
Herbivores
Plants
Deer, Canada goose
Carnivores
Meat
Hawk, polar bear
Omnivores
Meat and plants
Raccoon, pig
Predators and Prey
Animals that eat other animals must hunt for their food. An animal that hunts for its
food is a predator. Wolves, hawks, and Great Blue Herons are predators. An animal
that is hunted by a predator is the prey. Any animal eaten by another animal is the
prey. A Great Blue Heron is a predator. It catches and eats fish as its prey.
Draw lines from the predators to their prey.
cat
mosquito
bird
fish
spider
mouse
bat
worm
sea lion
fly
Special Consumers
All living things die. After they die, they are taken care of by a special group of
consumers. These consumers feed on dead material and waste produced by living
things. There are three main types of these special consumers:
• scavengers
• detritivores
• decomposers
Key Terms
consumer: a living things that eats (feeds on) other living things
predator: an animal that hunts another animal for food
prey: an animal that is hunted by another animal
1.2 Check and Reflect
6
Note: “detritus” is a term for waste produced by plants and animals. It is combined with a Latin word, vorare, which
means to devour. A detritivore is a consumer that devours waste left by plants and animals.
Vultures and crows are scavengers. Scavengers
feed off animals that are already dead. Without
scavengers there would be dead bodies lying all
over the ground in every ecosystem.
Why would you call a crow a scavenger?
A crow serves a useful purpose
in ecosystems.
It feeds off dead animals.
An earthworm is a detritivore. Detritivores feed off
waste products from other living things and dead
insects. Waste products allow the earthworm to get
the nutrients it needs. It then produces waste that is
returned to the soil, improving the quality of the
soil for plants.
A mushroom is a decomposer. Decomposers are
living things that break down waste products and
dead plants and animals into smaller pieces.
Bacteria are also decomposers. Without
decomposers, dead leaves, trees, and other plants
would never disappear. Like detritivores,
decomposers return good nutrients to the soil for
plants to use.
Earthworms feed off the wastes
of other living things.
Mushrooms are one of the types
of decomposer that breaks down
dead plant material.
Worm—waste product and dead insect;
Mushroom—leaf; Crow—dead insect
Some special consumers help to get rid of dead things in ecosystems.
Draw arrows from each of the special consumers to the thing it consumes.
Key Term
decomposer: a living thing that breaks down dead plants, animals, and waste products into
smaller pieces
Section 1.3
7
Food Chains
All animals need to eat in order to survive. Look how the wolf below gets
the energy
it needs.
small plants (sedges)  caribou  wolf
The wolf is a carnivore and it eats the caribou to get the energy it needs to
survive. The caribou is a herbivore and eats small grasses and other plants to
get the energy it needs to survive. This feeding relationship is called a food
chain. A food chain is a way to show how each consumer gets energy. Food
chains can be long or short, but they all begin with plants.
Look at the living things below and use the blank lines under the pictures to
create three food chains.
All of these living things are part of food chains.
plants  rabbit  fox
grain  chicken  adult
grass  cow (milk)  child
Section 1.3
8
1.3
Check and Reflect
1. Beside each description, write the word that describes it.
herbivore
scavenger
carnivore
predator
(a) an animal that eats meat
carnivore
(b) an animal that hunts other animals for food
predator
(c) an animal that eats dead animals but does not often kill them
itself
scavenger
(d) an animal that eats plants
herbivore
2. Read the following statements about organic matter. If they are true,
circle T; if they are false, circle F.
(a) A scavenger is not involved in recycling organic matter.
(b) A decomposer is not involved in recycling organic matter.
(c) A producer is not involved in recycling organic matter.
(d) A detritivore is not involved in recycling organic matter.
3. A mushroom is an example of
(a) a decomposer
(b) a herbivore
(c) a scavenger
(d) a producer
4. A food chain always begins with the Sun and
(a) a consumer
(b) a decomposer
(c) a herbivore
(d) a producer
T
T
T
T
F
F
F
F
.
.
5. Your pet dog likes to eat meat, but he also enjoys nibbling on grass,
garden peas, and berries. Based on what he eats, your dog is
.
(a) a herbivore
(b) a carnivore
(c) a decomposer
(d) an omnivore
6. A Venus fly trap is a plant that catches and eats insects. It needs several
hours of sunlight a day, like other plants. It can therefore be described as
.
(a) a herbivore and a carnivore
(b) a producer and a scavenger
(c) a carnivore and a producer
(d) a decomposer and a producer
Section 1.3
9