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The living planet
We depend on nature for lots of things, from food to medicines,
but most people are unaware of benefits provided by intact
ecosystems and only when we begin to lose these benefits, we
realize how valuable they are. This Unit deals with ecosystems
and biomes. It also explains how food chain works.
Answer the following questions.
a.
b.
c.
d.
What does the word “ecosystem” mean to you?
Do you know the difference between an ecosystem and a biome?
Have you already studied the “food chain” in your Science lessons?
What can you say about the food chain?
What is an ecosystem?
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Read the text, then label each paragraph with one
of the titles below.
Par.
Par.
Par.
Par.
Par.
Par.
1
1
2
3
4
5
6
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a.
b.
c.
d.
e.
f.
Size of ecosystems
Ecological factors
Definition of ecosystem
The role of Man
Kinds of ecosystems
Relations among species
PAR. 1 - A central principle of ecology is that
each living organism has a continual
relationship with every other element that
makes up its environment. The sum total of
interacting living organisms (the biocoenosis)
and their non-living environment (the biotope)
is called an ecosystem.
PAR. 3 - Ecosystems can be roughly divided
into:
• terrestrial ecosystems (forests, plains,
mountains and so on)
• freshwater ecosystems (lakes, ponds and
rivers)
• marine ecosystems (seas and oceans)
PAR. 2 - Ecosystems can be of any size, for
example, a rock and the plant life growing on it
might be considered an ecosystem. This rock
might be in a plain, with many other rocks, small
grass , and grazing animals – this, too, is an
ecosystem. This plain might be in the tundra,
which is also an ecosystem. The surface of the
Earth, all the matter which composes it, the air
and all living organisms can be considered one
huge ecosystem.
PAR. 4 - Ecological factors that affect a given
environment are usually divided into two
groups: abiotic and biotic. Abiotic factors are
geological, geographical, hydrological and
climatological parameters. A biotope is a region
characterized by a particular set of abiotic
ecological factors. Specific abiotic factors
include:
• water, which is an essential element to life;
• air, which provides oxygen, nitrogen, and
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
carbon dioxide to living species and allows
the dissemination of pollen and spores;
• soil, a source of nutriment and physical
support;
• temperature, which should not exceed
certain extremes;
• light, which provides energy to the
ecosystem through photosynthesis.
PAR. 5 - Biotic factors are considered either
intraspecific or interspecific relations.
Intraspecific relations are those established
between individuals of the same species, forming
a population. They are relations of cooperation or
competition with division of the territory, and
sometimes organization in hierarchical societies.
Interspecific relations are the interactions
between different species and are usually
described according to their beneficial,
detrimental, or neutral effect (for example,
mutualism or competition). The most significant
relation is the relation of predation (eat or be
eaten), which leads to the essential concepts in
the ecology of food chains (for example, grass is
consumed by a herbivore, itself consumed by a
carnivore, itself consumed by a larger carnivore).
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PAR. 6 - Man’s survival and well-being depend
largely on the food he eats, such as fruit,
vegetables and meat. It also depends on his
association with other living things. For
example, some bacteria help him digest certain
food. Man’s social and cultural surroundings
are an important part of his biotic environment.
His highly developed nervous system has made
memory, reason and communication possible.
Human beings teach their children what they
have learnt. By passing on knowledge, man has
developed art, music, literature, religion,
technology and science. Man’s biological and
cultural inheritance have enabled him to
advance beyond any other animal in controlling
the environment.
Find the English translation of these words in
the text.
a. immenso: ..........................................
b. permette: ..........................................
c. approssimativamente: ........................
d. nocivo: ..............................................
e. eredità: .............................................
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Answer the following questions.
a.
b.
c.
d.
e.
f.
4
What is an ecosystem?
How wide can an ecosystem be?
What are the factors that affect an ecosystem?
What are the specific abiotic factors?
How can the biotic factors be considered?
What does Man’s well-being depend on?
Hopetoun Falls, Australia. Example
of freshwater ecosystem.
Write down the answers and join them into a brief passage about ecosystems.
GLOSSARY
GLOSSARY
to affect: influire su.
grass: erba.
to graze: pascolare.
hierarchical: gerarchico.
highly: altamente.
to make up: formare.
pollen: polline.
through: attraverso.
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
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The food chain
A food chain shows how each living thing gets
its food. Some animals eat plants and some
animals eat other animals. Each link in this
chain is food for the next link. A food chain
always starts with plant life and ends with an
animal. Each species occupies a particular
position known as a trophic level.
Link 1. Plants are called producers because
they are able to use light energy from the sun
to produce food (sugar) from carbon dioxide
and water through photosynthesis.
Link 2. Animals cannot make their own food
so they must eat plants and/or other animals.
They are called consumers. There are three
groups of consumers:
a. animals that eat only plants are called
herbivores or primary consumers.
b. animals that eat other animals are called
carnivores and are
• secondary consumers (carnivores that
eat herbivores), or
• tertiary consumers (carnivores that eat
other carnivores)
c. animals and people which eat both
animals and plants are called
omnivores.
Link 3. Then there are
decomposers – bacteria and
fungi – which feed on
decaying matter. The
decaying process releases
mineral salts back into
the food chain for
absorption by
plants as
nutrients.
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In a food chain, energy is passed from one link
to another. When a herbivore eats, only a
fraction of the energy that it gets from the plant
food becomes new body mass. The rest of the
energy is lost as waste or used by the herbivore
to carry out its life processes, such as
movement, digestion, reproduction and so on.
Therefore, when a herbivore is eaten by a
carnivore, it passes only a small amount of the
total energy that it has received to the
carnivore. The carnivore then has to eat many
herbivores to get enough energy to grow. In a
food chain, at each link the amount of energy
decreases more and more. Because of the loss of
energy at each link, ecosystems develop what
are called “ecological pyramids”.
For example, a simple ecological pyramid links
the trees and shrubs , the giraffes that eat them,
and the lions that eat the giraffes.
A change in the size of one population in a food
chain will affect the other populations. For
example, if there are too many giraffes, there
will be insufficient trees and shrubs to eat, so
many giraffes will die. Fewer giraffes also means
less food for the lions, which could starve
to death. But if there are fewer lions,
the giraffe population will increase.
Most animals are part of more
than one food chain and eat
more than one kind of food in
order to get energy. These
form a food web.
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
An example of
ecological pyramid.
5
Match each word with its definition.
a.
b.
c.
d.
e.
f.
g.
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link
chain
waste
herbivores
decaying
bacteria
web
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1.
2.
3.
4.
5.
6.
7.
microscopic organisms
network
animals that feed on plants
connection
decomposing
series of connected things
material to be thrown away
Put the words into the correct order to make questions.
a. food/a/does/show/what/chain ...................................................................................?
b. and/food/a/where/chain/end/does/start ...................................................................?
c. producers/are/called/plants/why ................................................................................?
d. difference/is/herbivores/between/and/what/the/carnivores ........................................?
e. are/carnivores/what ...................................................................................................?
f. do/decomposers/on//what/feed ................................................................................?
g. pyramid/an/is/what/ecological ...................................................................................?
h. chain/a/is/than/smaller/food/a/web/food .................................................................?
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Write down the answers to the previous questions.
a. ....................................................................................................................................
b. ....................................................................................................................................
c. ....................................................................................................................................
d. ....................................................................................................................................
e. ....................................................................................................................................
f. ....................................................................................................................................
g. ....................................................................................................................................
h. ....................................................................................................................................
8
Use the words to complete a marine food chain and draw the ecological pyramid.
a. krill
b. killer whale
c. squid
d. seal
e. plankton
f. fish
.........................................................................................................................................
.........................................................................................................................................
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Now think about a food chain or a food web on your own. Draw it in your exercise-book, then explain
it to your schoolmates and your teacher.
GLOSSARY
GLOSSARY
both … and: sia … che.
carbon dioxide: anidride carbonica.
to carry out: compiere.
enough: abbastanza.
own: proprio.
shrubs: arbusti.
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
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From ecosystems to biomes
Ecosystems are not isolated from each other, but
interrelated. For example, water may flow
between ecosystems by means of a river or an
ocean current. Some species of animals, such as
salmon, move between marine systems and
freshwater systems. The relationships between
the ecosystems lead to the concept of “biome”.
A biome is a geographically defined area of
ecologically similar conditions such as
communities of plants, animals, and soil
organisms. Biomes are defined by factors such
as plant structures (trees, shrubs, and grasses),
leaf types (broadleaf and needleleaf, and so
on), plant spacing (forest, woodland, savanna),
and climate. An ecosystem has many biotopes
and a biome can have many ecosystems. Biomes,
like ecosystems, can be classified as:
1. terrestrial (land) biomes
2. freshwater biomes
3. marine biomes.
Biomes are often known by local names. For
example, a temperate grassland or shrubland
biome is commonly known as steppe in central
Asia, prairie in North America, and pampas in
South America. Tropical grasslands are known as
veldt in Australia, whereas in Southern Africa
they are known as savanna.
Climate is a major factor determining the
distribution of terrestrial biomes. Among the
important climatic factors are:
• latitude: arctic, boreal, temperate,
subtropical, tropical climates.
• humidity: humid, semi-humid, semi-arid,
and arid.
• elevation: increasing elevation causes a
distribution of habitat types similar to that
of increasing latitude.
The most widely used systems of classifying
biomes correspond to latitude and humidity.
Biodiversity generally increases from the poles
towards the equator and increases with humidity.
The map of terrestrial biomes
1.
2.
3.
4.
5.
6.
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Ice sheet & polar desert
Tundra
Taiga
Temperate broadleaf forest
Temperate steppe
Subtropical rainforest
7.
8.
9.
10.
11.
12.
Mediterranean vegetation
Monsoon forest
Arid desert
Xeric shrubland
Dry steppe
Semiarid desert
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
13.
14.
15.
16.
17.
18.
Grass savanna
Tree savanna
Subtropical dry forest
Tropical rainforest
Alpine tundra
Montane forest
10
Decide if the following statements are true (T) or false (F) and correct the false ones.
T
F
a. Ecosystems and biomes are the same thing.
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b. The kind of trees is essential to classify a biome.
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c. Biomes can be classified in the same way as ecosystems.
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d. Biomes take their names from local languages.
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e. Climate isn’t an important factor.
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f. Seasonal variations in rainfalls must be taken into consideration.
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g. Latitude is the only system to classify biomes.
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T
F
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11
Match the following words with their definitions.
a.
b.
c.
d.
e.
f.
g.
12
plant
freshwater
humidity
seasonal
rainfall
widely
poles
1.
2.
3.
4.
5.
6.
7.
Not salty water.
To a large extent or degree.
The two points at the top and bottom of the Earth.
Living organism usually with roots and leaves.
Happening during a particular season.
Degree of moisture.
Total amount of rain falling in an area in a given time.
Listen to the definition of climate and choose T if the statement is true or F
if the statement is false. Correct the false ones in your exercise book.
a. The word “climate” derives from ancient Greek.
b. Climate is the weather in a place usually during 40 years.
c. A popular phrase says that “the climate is what you get and the weather
is what you expect”.
d. Lots of variables determine the climate.
e. Alteration in the quantity of greenhouse gases can lead to global cooling.
f. Climatologists are not interested in climate changes.
13
DICTATION. Listen to the CD again (or your teacher reading)
and write down the text about “CLIMATE”.
GLOSSARY
GLOSSARY
to flow: scorrere.
to increase: aumentare.
plant spacing: distanza tra le piante.
widely: ampiamente.
THE LIVING PLANET by D.Bottero - R.Beolé © Editrice EDISCO, Torino
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