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1.2
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The Roles of Producers
Here is a summary of what you will learn in this section:
• Plants interact with the Sun’s light and heat to support life on Earth.
• Plants are the only organisms that can use the Sun’s energy to produce food.
• Other living things interact with plants as food or to find or make shelter.
On a sunny day, you can feel the warmth of the Sun on your
face. You might even have to shade your eyes because of its
bright light. Plants also interact with the Sun’s heat and light.
You can notice this in the spring when the Sun’s heat melts the
snow and warms the soil. Plants start to poke up through the
warm soil. They grow rapidly as the days get longer and more
light is available.
The Sun is an essential abiotic element in most ecosystems
(Figure 1.13). The two forms of energy from the Sun — light
and heat — are important to most life forms on Earth.
A8 Starting Point
Figure 1.13 Living things interact
with the light and heat from the Sun.
Skills A C
The Year with No Summer
In 1815, Mount Tambora erupted in the Pacific
Ocean, east of Java, spewing 150 million tonnes
of volcanic dust high into Earth’s atmosphere.
The ash gradually surrounded Earth and filtered
the Sun’s light for months.
The summer months of 1816 were known as
“the year with no summer” in North America
and parts of Europe. Snow covered areas
around Montreal, Quebec City, and the New
England states for brief periods in June. Crops
sprouted very late and were killed by an early
hard frost in September. Families had no food
for themselves or their livestock for the coming
winter.
Consider This
1. How would the lack of sunlight affect the
normal interactions between biotic and
abiotic elements?
2. Historical documents report that people
had to abandon their farms and towns. Do
you think that would happen again if the
Sun’s rays were blocked?
Figure 1.14 Volcanoes can spew huge quantities of
dust and gases high into the air.
Ecosystems are communities where biotic and abiotic elements interact.
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How Producers Use the Sun’s Energy
Plants are called producers. Producers can make their own
food to supply the matter and energy they need to survive.
All sizes and types of green plants, from tiny algae to the
largest trees, are producers (Figure 1.15).
Photosynthesis
Figure 1.15 The algae floating on
this pond and the larger plants in the
upper part of the photo are all
producers.
Producers use a process called photosynthesis to make food.
Photosynthesis is a chemical reaction that takes place in
the leaves of green plants when the Sun’s light is present.
The green colour visible in most leaves is a compound called
chlorophyll, which is needed in the chemical reaction.
Through photosynthesis, producers combine carbon dioxide, a
colourless, odourless gas from the air, and water from the soil.
This combination forms a sugar product called glucose and a
waste product — oxygen (Figure 1.16). The oxygen is released
back into the air through tiny pores in the plants’ leaves.
6CO2 + 6H2O (in the presence of sunlight and chlorophyll) ➝ C6H12O6 + 6O2
Figure 1.16 Plants produce both food and oxygen during photosynthesis.
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UNIT A
Interactions in the Environment
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Producers’ Roles
All ecosystems have producers. Producers are part of the
interactions that support biotic elements in an ecosystem.
Producers have three roles in an ecosystem:
1. They produce oxygen.
2. They supply food.
3. They provide shelter.
Producers Produce Oxygen
Plants and plant-like biotic elements maintain Earth’s supply
of oxygen. Oxygen is one of the basic needs of living things.
Figure 1.17 A variety of animals
dine on many different parts of
producers.
Producers Supply Food
Producers are the only biotic elements that can make their own
food. All other living things must find food to eat in order to
get all the matter and energy they need to survive. Some of
these living things eat only producers. For example, some
insects, deer, rabbits, and cows eat only plants. Others eat the
living things that eat producers. Birds eat insects. Foxes eat
rabbits. Humans eat cows. This means that all feeding
interactions begin with producers.
Producers Provide Shelter
In ecosystems, biotic elements often shelter in plants or use
plants to make their shelters. Birds nest in tree branches.
Squirrels and chipmunks nest in hollowed-out tree trunks.
Insects can live in or on trees, bushes, shrubs, and mosses.
Fish shelter in the cover of aquatic plants in ponds and rivers.
Decaying logs, beaver dams, and birds’ nests are a very few
examples of the shelter provided by or supported by plants in
ecosystems.
Interactions in Ecosystems
Ecosystems are busy places, as biotic elements interact with
other elements to meet their basic needs. Producers take in the
Sun’s energy while they also take in water and nutrients from
the soil. Photosynthesis is under way. Meanwhile, other biotic
elements take shelter or feed.
Ecosystems are communities where biotic and abiotic elements interact.
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Figure 1.18 Some interactions in
ecosystems harm one of the
participants.
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Some interactions in an ecosystem can harm one of the
participants. For example, when a garter snake eats a frog,
the frog dies, while the garter snake takes in nutrients
(Figure 1.18). Other interactions benefit both participants.
For example, when a bee feeds on nectar, it also gathers and
distributes pollen. This helps the plants to reproduce.
Constant interactions are part of all ecosystems. Aboriginal
peoples describe these interactions as “connections.”
These connections mean that when something changes in an
ecosystem, the change will affect other parts of the ecosystem.
For example, when a beaver builds a dam and floods an area,
the plants that cannot survive in wet conditions will die. The
living things that depend on those plants may have trouble
surviving.
A9 Learning Checkpoint
Plants and the Sun
1. Describe the interaction between the Sun
and producers.
4. What are the roles of producers in an
ecosystem?
2. Explain why this interaction is important.
5. Why does a fox need to be in an
ecosystem that includes grass?
3. What is the name of the interaction?
Populations and Communities
Figure 1.19 The population of ducks is part of a pond
community.
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UNIT A
Interactions in the Environment
As you consider interactions in ecosystems, you will
not be looking at individual biotic elements. Instead
you will be looking at populations and communities.
Populations are groups of individuals that belong
to the same species and live in the same area at the
same time. Species are the most closely related
groups of living things in an ecosystem. The
members of a species can reproduce with each other
and their offspring can reproduce.
A community is made up of populations of
different species that live and interact in a habitat.
The interactions of the populations with each other
and the local abiotic elements make up the ecosystem.
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For example, the mallard ducks in Figure 1.19 are members
of a population. Around them is a pond habitat, with
populations of various plants, geese and other birds, insects,
and mammals. Together these populations make up the pond
community. The pond ecosystem includes the community’s
interaction with abiotic elements in the pond, such as the
water, rocks, and soil, and with each other. Within each
ecosystem, the biotic elements depend on other biotic elements
and abiotic elements for survival.
Take It Further
Humans can eat both meat and
plants. However, some humans
prefer to eat only plants and
products made from plants.
Find out how vegetarians get all
the nutrients they need from
plants. Begin your research at
ScienceSource.
A10 During Reading
Reading like a Writer
Understanding the organizational pattern used
in a piece of non-fiction writing can help you as
a reader. Much of the information presented in
this chapter is written as a description. Writers
use descriptive text pattern when they want to
share the characteristics of something, such as a
concept, animal, plant, or place. Descriptive text
paints a visual picture with words.
Give this type of writing a try. The following
paragraph describes a species, population, and
community of producers in an ecosystem.
In Ontario, farmers grow many different
types of fruits and vegetables. One popular
type of fruit is the McIntosh apple. Many
farms grow large populations of McIntosh
apples. On other farms, the McIntosh
apple is just one of the many different
fruits and vegetables that are grown in that
farm community.
Using the information you have read in this
section, add details to this paragraph using the
three Es of writing. The table below summarizes
the three Es and key questions you can ask.
When you have finished adding details to
your paragraph, exchange it with a partner and
read each other’s writing. Suggest one or two
details that could be added to the paragraph.
Incorporate your partner’s suggestions into
your paragraph.
Es for Stretching Ideas
Key Questions to Consider
Expand
How is this so?
Extend
Such as? For example?
Elaborate
And an example is . . .
This looks like . . .
Tell me more about . . .
Ecosystems are communities where biotic and abiotic elements interact.
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A11 Quick Lab
How an Abiotic Element Affects Producers
Purpose
Questions
To find out how sunlight affects Canada’s
producers
3. How was the amount of sunshine related
to the growth of plants?
4. What other abiotic elements could affect
plant growth? Give some examples and
describe their possible impact.
Materials & Equipment
■
■
■
potato production statistics (by province)
wheat production statistics (by province)
apple production statistics (by province)
5. How does organizing the statistical
information in a graph or a chart help you
state and defend a clear conclusion?
Procedure
6. What are some of the factors farmers need
to consider when looking for new land to
grow crops on?
1. Look at the map in Figure 1.20 below
showing the average annual hours of
sunshine in Canada. What patterns do you
notice among provinces with similar hours
of sunshine? Different hours of sunshine?
7. How does the growing season (hours of
sunlight) have an effect on where people
would choose to live?
2. Compare the production of farm products
to the average hours of sunshine of the
areas where they are most commonly
grown. What trends do you notice?
8. What role does Canada’s climate play in
industries related to producers?
Sunshine
Average annual hours
1200
1600
2000
1800
1800
Resolute
179
1800
1800
253 number of days
Whitehorse
298
with some sun
Iqaluit
249
Prince Rupert
245
1400
Churchill
279
Goose Bay
265
St. John’s
268
Edmonton
322
Vancouver
289
Regina
320
Winnipeg
312
Quebec
284
2400
N
0
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UNIT A
500
1000 km
Interactions in the Environment
London
294
Ottawa
309
Charlottetown
270
Saint
John
280
Halifax
290
Figure 1.20 The average amount
of sunshine that an area receives
will affect the crops that are
grown there.
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CHECK and REFLECT
Key Concept Review
1. List two ways the Sun supports life.
2. Explain how the plants in and around a
meadow provide habitat for these
animals: butterfly, field mouse, owl.
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6. Plants that live in shallow water have the
same roles as plants on dry land. Describe
the roles of plants like the ones shown
below. Give an example of an interaction
between one of the plants shown and
another biotic element in the ecosystem.
3. Explain why photosynthesis is important
for ecosystems everywhere.
Connect Your Understanding
4. Forests and meadows are often cut down
to make way for farms or large numbers
of new homes. What are some of the
elements of ecosystems that are lost when
plants in these areas are removed?
5. How would planting a variety of plants in
a vacant lot help establish an ecosystem
in that location?
Practise Your Skills
7. How can gathering and organizing
information about ecosystems help you
better understand the interactions among
the different elements in an ecosystem?
For more questions, go to ScienceSource.
A12 Thinking about Science and the Environment
ST
SE
Connections
On page 17, you read about “the year with no
summer.” That was 1815, when many eastern
North Americans could not grow enough food
for the next winter. No one knew then that the
eruption of a volcano in the Pacific Ocean had
caused their troubles.
Scientists now understand that the
connections among all biotic and abiotic
elements on Earth make survival of biotic
elements possible. These connections can be
global or within a tiny ecosystem in a puddle. A
change in one element in an ecosystem has a
ripple effect — like a pebble dropped in a pond —
on all the other elements in an ecosystem.
Consider This
1. Do you think it is acceptable for someone
to release old chemicals into a stream?
Explain your answer.
2. Do you think it is acceptable for large
industries to release chemicals into the air?
Explain your answer.
Ecosystems are communities where biotic and abiotic elements interact.
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