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Protecting Ireland’s Biodiversity
Protecting Ireland’s
What is ecology?
Saprophytes are a particular group of decomposers – they are
bacteria and fungi that feed on and decompose dead organic matter.
Saprophytes, besides being food for other organisms and clearing
detritus, also play a vital role in the recycling of mineral nutrients.
This lesson introduces the subject of ecology and the concept
of the ecosystem. We then go on to discuss habitats, the food
chain, and the pyramid of numbers. We will also learn about
Teagasc, the state agency providing environmental advice,
research and training.
The oak forest was the most widespread ecosystem in Ireland before
the arrival of humans. An oak forest ecosystem is twice as productive
Saprophytes
arehasatwice
particular
group of decomposers – they are
as agricultural land. A hectare
of oak forest
as much organic
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and fungi
that
matter remaining than abacteria
hectare of wheat
has, after
the feed
plants on
haveand
takendecompose dead organic matter.
what they need for theirSaprophytes,
energy needs.
besides being food for other organisms and clearing
What is ecology?
Ecology
the studyintroduces
of the interactions
livingof
organisms
andand
of
This islesson
thebetween
subject
ecology
the concept
their interactions with their abiotic environment.
detritus, also play a vital role in the recycling of mineral
nutrients.
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of the ecosystem. We then go on to discuss habitats, the food
learn about
Teagasc, the state agency providing environmental advice,
The boundaries between ecosystems are not sharply defined but
research and training.
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gradual. This means that there can be considerable interchange between
Living organisms live in communities. A community is a group of species
chain,with
and
of same
numbers.
We will plus
also
interacting
eachthe
otherpyramid
and living in the
area. The community
the abiotic environment with which it interacts is called an ecosystem.
ecosystems. All the ecosystems of our planet are connected to form a
Ecology is the study of the interactions between living organisms
giant ecosystem called the biosphere. The biosphere is the layer of living
their interactions
theirextending
abiotic environment.
organisms
that covers with
the earth
in depth from 3 km below
ground to the highest level of the atmosphere.
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the abiotic
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between habitat and ecosystem?
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Ecosystem refers to a community whereas habitat is restricted to an
gradual.
This means
thatis there
canwhere
be considerable
interchange between
individual
species.
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the place
the species is living
ecosystems.
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to form a����
and
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organisms that covers the earth extending in depth from 3 km below
Adaptations
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highest
of the atmosphere.
gradually as a result of evolution by natural selection. Human induced
environmental changes to habitats or ecosystems often lead to the
extinction of species because they cannot tolerate the new conditions.
Therefore, the conservation of biodiversity demands the maintenance or
re-establishment of habitats and ecosystems.
What is the difference
between habitat and ecosystem?
Ecosystem
to a community process?
whereas habitat is
Isn’t
life anrefers
energy-requiring
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Fig.1 Energy flow in an ecosystem
What��������
are the reasons for
constructing a pyramid of
What is a food chain?
A pyramid of numbers attempts to discover
of an ecosystem as a bar chart by counting
each trophic level. The number of organism
pyramid. This is due to the large energy los
trophic level. As a result there is less energy
up the pyramid.
A food chain is a sequence of species, each being the source of food for
the next species. The position of a species in a food chain is called its
restricted
an
trophicto
level.
individual species. The habitat is the place where the species is living
Adaptations are ‘solutions’ to environmental ‘problems’ and have��������
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as a result of evolution by natural selection. Human induced
Isgradually
food just
a source of energy?
environmental changes to habitats or ecosystems often lead to the
No. Food made by photosynthesis, is also a source of organic materials
extinction of species because they cannot tolerate the new conditions.
needed for the physical construction of living organisms. Approximately
Therefore,
conservation
of biodiversity
the maintenance or
90%
of the food the
obtained
by an organism
is used as a fueldemands
for energy and
re-establishment
of habitats
and ecosystems.
10%
or less is used as building
material.
Producers obtain their food by making it for themselves from inorganic
materials, either by photosynthesis or chemosynthesis. Consumers obtain
their food by feeding on organic materials made by other organisms.
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and –tothis
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to a 100 has
watt light
bulb. We
obtain
most of distribution may
beenergy
limited
to onlyrespiration
a small ofpart
of Plants
the ecosystem
where
our
by aerobic
‘food’.
originally made
this a unique set of
food
during photosynthesis
conditions
occurs. when light energy was converted to chemical
energy. Therefore light is the energy for life.
What is the role of a speci
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Fig.1 Energy flow in an ecosystem
100
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What is a food chain?
Fig.2 Example of a food chain
Most species are members
of more
than one
chain in the
A food
chain
is afood
sequence
ofcommunity.
species, each
Amalgamating all the food
chains
one flow chart
a food
the
nextintospecies.
Theproduces
position
of aweb.
species
Isn’t life an energy-requiring process?
level.
The food web gives all trophic
the feeding
connections in the community and
a clearer picture of the complexity of energy flows. It also indicates the
Animals that feed on plants are called herbivores. Those that feed on other
Yes
it
is.
The
average
human
at
rest
uses
100
joules
of
energy
every
delicate
balance
of
nature
because
if
one
species is lost, or if its population
animals are carnivores. If their food consists of plants and animals, they
is changed
dramatically, all the other species will be affected. Pollution can
– this
is organisms
equivalent
a 100
watt light
bulb.
We obtain
most of
aresecond
omnivores.
If dead
areto
their
food source
they are
called
very destructive in ecosystems if it leads to the elimination of sensitive
decomposers.
make up
about 80% of
ecosystem.
our energyOmnivores
by aerobic
respiration
ofeach
‘food’.
Plants originally be
made
this
species or severe reduction of their populations.
9
5 x 10
being
the
source of food for
in a food chain is called its
Relative Number of Organisms
F
food during photosynthesis when light energy was converted to chemical
energy. Therefore light is the energy for life.
Is food just a source of energy?
No. Food made by photosynthesis, is also a source of organic materials
needed for the physical construction of living organisms. Approximately
90% of the food obtained by an organism is used as a fuel for energy and
10% or less is used as building material.
Producers obtain their food by making it for themselves from inorganic
materials, either by photosynthesis or chemosynthesis. Consumers obtain
their food by feeding on organic materials made by other organisms.
Animals that feed on plants are called herbivores. Those that feed on other
animals are carnivores. If their food consists of plants and animals, they
are omnivores. If dead organisms are their food source they are called
decomposers. Omnivores make up about 80% of each ecosystem.
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Fig.2 Example of a food chain
Most species are members of more than one food chain in the community.
Amalgamating all the food chains into one flow chart produces a food web.
The food web gives all the feeding connections in the community and
a clearer picture of the complexity of energy flows. It also indicates the
delicate balance of nature because if one species is lost, or if its population
is changed dramatically, all the other species will be affected. Pollution can
be very destructive in ecosystems if it leads to the elimination of sensitive
species or severe reduction of their populations.
Protecting Ireland’s Biodiversity
d’s Biodiversity
What is ecology?
Saprophytes are a particular group of decomposers – they are
bacteria and fungi that feed on and decompose dead organic matter.
Saprophytes, besides being food for other organisms and clearing
detritus, also play a vital role in the recycling of mineral nutrients.
This lesson introduces the subject of ecology and the concept
of the ecosystem. We then go on to discuss habitats, the food
chain, and the pyramid of numbers. We will also learn about
Teagasc, the state agency providing environmental advice,
research and training.
The oak forest was the most widespread ecosystem in Ireland before
the arrival of humans. An oak forest ecosystem is twice as productive
as agricultural land. A hectare of oak forest has twice as much organic
matter remaining than a hectare of wheat has, after the plants have taken
what they need for their energy needs.
Ecology is �����
the study of the interactions between living�����
organisms and of
their interactions with their abiotic environment.
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�������������������
The boundaries between ecosystems ��������
are not sharply defined but
����������
gradual. This means that there can be considerable interchange between
ecosystems. All the ecosystems of our planet are connected to form a
giant ecosystem called the biosphere. The biosphere is the layer of living
organisms�������
that covers the earth extending in depth from 3 km below
ground to the highest level of the atmosphere.
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What is the difference
between habitat and ecosystem?
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Living organisms live in communities. A community is a group of species
interacting with each other and living in the same area. The community plus
the abiotic environment with which it interacts is called an ecosystem.
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Ecosystem refers to a community whereas habitat is restricted to an
individual species. The habitat is the place where the species is living
and to which the species has adapted.
The species’ distribution may
���������������
be limited to only a small part of the ecosystem where a unique set of
conditions occurs.
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Teagasc
is a state organisation which provides research,
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advisory and training services for the agriculture and food
industry in Ireland.���������
Over 1,500 staff work at over 100 locations
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throughout the country. They work with
all sectors
of the
What
is the role
of a speci
agriculture and food industries and with
development
in rural
a community
called?
agencies. Teagasc employs over 200 scientists and 300
Every species in the community is said t
research technicians in research, and many
specialistto be the mann
A niche other
is often considered
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environment in the struggle to obtain its esse
staff
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organism’s most important resource, so all f
parts of a species’
One of the organisation’s objectivesfood
is aretovitalprotect
and niche.
Adaptations are ‘solutions’ to environmental ‘problems’ and have arisen
enhance
biodiversity
on
farmland.
This
programme
includes
Fig.3 Food web
Fig.1 Energy flow in an ecosystem
gradually as a result of evolution by natural selection. Human induced
the provision of advice to farmers onWhat
how to
the
areprotect
the reasons
for
environmental changes to habitats or ecosystems often lead to the
environment in designated areas. These
areas
include
extinction of species because they cannot tolerate the new conditions.
constructing a pyramid of
What
isconservation
the role
of a demands
species
Therefore, the
of biodiversity
the maintenance or
habitats of high conservation value that contain rare or
What is a food chain?
A pyramid of numbers attempts to discover
re-establishment of habitats and ecosystems.
important
species,
species-rich
sand
in a community called?
of angrasslands,
ecosystem as a bar
chart by counting
A food chain is a sequence
of species, each
being thesuch
source as
of food
for
each
trophic level.
The number
the next species. The position
of a marshes,
species in a food
is called
its
dunes,
andchain
bogs.
Teagasc
also
provides
advice
to of organism
Every
species
in
the
community
is
said
to
occupy
a
particular
niche.
pyramid. This is due to the large energy los
Isn’t life an energy-requiring process?
trophic level.
farmers
on
the
protection
and
management
of
other
habitats
trophic level. As a result there is less energy
A niche is often considered to be the manner in which a species uses its
Yes it is. The average human at rest uses 100 joules of energy every
that commonly occur on Irish farmlandupe.g.
streams, rivers,
the pyramid.
environment
the struggle
to obtain
essential
resources.
second – this isinequivalent
to a 100
watt lightitsbulb.
We obtain
most of Food is every
ponds,
hedgerows,
field
margins,
and
woodland.
Ireland
our energy bymost
aerobic
respirationresource,
of ‘food’. Plants
this
organism’s
important
so alloriginally
factors made
connected
with gaining
food during
photosynthesis
light energy
was converted to chemical
has a wide diversity of wildlife habitats and it is particularly
food
are vital
parts of awhen
species’
niche.
energy. Therefore light is the energy for life.
important that they are protected. Its research aims to raise
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Is food just a source of energy?
practices
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What are the reasons for
5,000
Second
No. Food made by photosynthesis, is also a source of organic materials
on their land.
constructing
a pyramid
of numbers?
needed for the physical construction
of living organisms.
Approximately
Fig.2 Example of a food chain
106
90% of the food obtained by an organism is used as a fuel for energy and
You can visit www.teagasc.ie to find out about designated
are omnivores. If dead organisms are their food source they are called
decomposers. Omnivores make up about 80% of each ecosystem.
is changed dramatically, all the other species will be affected. Pollution can
www.teagasc.ie and at www.sciencetechologyaction.com
be very destructive in ecosystems if it leads to the elimination of sensitive
species or severe reduction of their populations.
A
pyramid
numbers
attempts
10%
or less isofused
as building
material.to discover and show the energy structure
and get fascinating information on habitats.
5 x 109
of
an ecosystem as a bar chart by counting the number of individuals
at are membersareas
Most species
of more than one food chain in the community.
Producers obtain their food by making it for themselves from inorganic
Amalgamating
each
trophic
level.
The number
of organisms
declines
as you go
up the all the food chains into one flow chart produces a food web.
materials,
either by
photosynthesis
or chemosynthesis.
Consumers
obtain
their food byThis
feeding
on organic
made by other
pyramid.
is due
to thematerials
large energy
loss organisms.
(about 90%) between
Relative Number of Organisms
The each
food web gives all the feeding connections in the community and
Find outof about
Teagasc,
the people
who work there
a clearer
energy flows.
It also indicates
the
trophic
level.
result
less energy
organisms
higherpicture of the complexity
Animals that
feedAs
on a
plants
arethere
called is
herbivores.
Thoseavailable
that feed onto
other
delicate balance of nature and
because
species
is lost, or if projects
its population
theif one
many
scientific
they are involved in at
animals
are carnivores. If their food consists of plants and animals, they
up
the pyramid.
100
5,000
106
5 x 109
Relative Number of Organisms
Tertiary Consumer
Secondary Consumer
Primary Consumer
Primary Producer
Trophic Level
Fig.4 Pyramid of numbers
Fig.5 Manmade lake
This manmade lake on farmland supports a variety of aquatic
invertebrates and plants, and is surrounded by common reed, shrubs
mature trees that provide habitat for terrestrial insects and birds.
F
Protecting Ireland’s Biodiversity
Protecting Ireland’s
What is ecology?
Saprophytes are a particular group of decomposers – they are
bacteria and fungi that feed on and decompose dead organic matter.
Saprophytes, besides being food for other organisms and clearing
detritus, also play a vital role in the recycling of mineral nutrients.
This lesson introduces the subject of ecology and the concept
of the ecosystem. We then go on to discuss habitats, the food
chain, and the pyramid of numbers. We will also learn about
Teagasc, the state agency providing environmental advice,
research and training.
The oak forest was the most widespread ecosystem in Ireland before
the arrival of humans. An oak forest ecosystem is twice as productive
as agricultural land. A hectare of oak forest has twice as much organic
matter remaining than a hectare of wheat has, after the plants have taken
what they need for their energy needs.
Syllabus Reference
Activities
Ecology is the study of the interactions between living organisms and of
their
interactions
with their abiotic
environment.
Leaving
Certificate
Biology:
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Practical Activities
Living
live in communities.
A community is 1.4.3
a groupBiosphere,
of species
Unit organisms
1.4.1 Ecology,
1.4.2 Ecosystem,
interacting with each other and living in the same area. The community plus
1.4.4
Habitat,
1.4.5
Environmental
Factors,
1.4.6
Energy
the abiotic environment with which it interacts is called an ecosystem.
gradual. This means that there can be considerable interchange between
Junior Certificate
Science:
ecosystems.
All the ecosystems
of our planet are connected to form a
giant
called the biosphere. The biosphere is the layer of living
1C7ecosystem
Ecology
organisms that covers the earth extending in depth from 3 km below
ground to the highest level of the atmosphere.
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Revise the following mandatory practical activities:
Flow,
1.4.7
Niche,
H.1.4.10
Pyramid
of
Numbers
(Extended
Study)
The boundaries between ecosystems are not sharply defined but
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Identify five fauna and
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What is the difference
between habitat and ecosystem?
Learning Objectives
������������
•
Identify and use various apparatus required for collection methods in
���������������
an ecological study.
•
Conduct a quantitative study of plants and animals of a sample area of
the selected ecosystem.
���������
•
Investigate any three abiotic factors present in the selected
What is the role of a speci
ecosystem.
���������
������������������������
Ecosystem refers to a community whereas habitat is restricted to an
individual species. The habitat is the place where the species is living
Ontocompleting
this
student
willmay
be
and
which the species
has section,
adapted. Thethe
species’
distribution
be limited to only a small part of the ecosystem where a unique set of
• Define
ecology
conditions
occurs.
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Investigative Activities
able to:
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•
in a community called?
Every species in the community is said t
A niche is often considered to be the mann
�����������
Identify
and record����
the common plants and
animalsinencountered
in its esse
environment
the struggle to obtain
�����������������
organism’s most important resource, so all f
every day life.
food are vital parts of a species’ niche.
• Record any feeding activity you observe – note the animal, time, place
Adaptations
arethe
‘solutions’
to environmental
‘problems’
and haveecosystems
arisen
• Outline
relationships
between
communities,
and the
Fig.1
Energy flow in an ecosystem
and food
source.
gradually as a result of evolution by natural selection. Human induced
biosphere
What are the reasons for
environmental changes to habitats or ecosystems often lead to the
• Record any adaptive feature you become aware
of in any of the
plants
extinction of species because they cannot tolerate the new conditions.
constructing
a pyramid
of
•
Differentiate
between
a
habitat
and
an
ecosystem
Therefore, the conservation of biodiversity demands the maintenance or
and animals.
What
is
a
food
chain?
A pyramid of numbers attempts to discover
re-establishment of habitats and ecosystems.
• Identify general groupings of organisms based on their foodAsources
of an ecosystem as a bar chart by counting
food chain is a sequence of species, each being the source of food for
each trophic level. The number of organism
the next species. The position of a species in a food chain is called its
•
Differentiate
between
a
food
chain
and
a
food
web
pyramid. This is due to the large energy los
Isn’t life an energy-requiring process?
trophic level.
trophic level. As a result there is less energy
Yes
is. The average
human of
at a
rest
uses 100
of energy every
• itExplain
the function
pyramid
ofjoules
numbers
up the pyramid.
second – this is equivalent to a 100 watt light bulb. We obtain most of
our energy by aerobic respiration of ‘food’. Plants originally made this
food during photosynthesis when light energy was converted to chemical
Indicate whether the following are true (T) or false (F)
energy. Therefore light is the energy for life.
True or False
Is
food justLearning
a source ofPoints
energy?
General
No. Food made by photosynthesis, is also a source of organic materials
needed
for the
physical construction
of living organisms.
Approximately
• Living
organisms
live in interactive
communities.
90% of the food obtained by an organism is used as a fuel for energy and
10%
less is used
as buildinginfluence
material.
• or
Living
organisms
and are influenced by
��������
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by drawing a circle around
T or F.
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(a) Ecology is��������
the study
��������
organisms.
their abiotic
��������
of the�������
interactions between living
(b) A group ofFig.2
interacting
species
in an area is known as a
Example of
a food chain
habitat.
T
100
F Tertiary Co
5,000
106
T
5 x 109
Most species are members of more than one food chain in the community.
environment.
Producers
obtain their food by making it for themselves from inorganic
(c) The community plus its abiotic environment is a habitat.
T
Amalgamating all the food chains into one flow chart produces a food web.
materials, either by photosynthesis or chemosynthesis. Consumers obtain
• food
Theby
features
oforganic
each materials
speciesmade
are by
solutions
to the problemsThe
of food
life in
their
feeding on
other organisms.
Relative
Number
of
Organisms
web gives all(d)
theThe
feeding
connectionsisinearth’s
the community
atmosphere
layer ofand
living organisms.
T
their particular habitat. Habitat destruction is a major cause ofa clearer
species
picture of the complexity of energy flows. It also indicates the
Animals that feed on plants are called herbivores. Those that feed on other
delicate
balance
of
nature
because
if
one
species
is
lost,
or
if
its
population
extinction.
animals
are carnivores. If their food consists of plants and animals, they
(e) Sunlight is the major source of energy maintaining the
T
is changed dramatically, all the other species will be affected. Pollution can
are omnivores. If dead organisms are their food source they are called
biosphere.
be
very
destructive
in
ecosystems
if it leads to the elimination of sensitive
• Maintaining
biodiversity
depends
on
habitat
conservation.
decomposers.
Omnivores
make up about
80% of
each
ecosystem.
species or severe reduction of their populations.
Second
F
F
F
F
F
•
The sun is the source of energy for life on planet earth.
(f) Plants are producers.
T
F
•
About 90% of food is used as a fuel, for energy, at each trophic level.
T
F
•
Food chains are short.
(g) Producers are micro-organisms that feed on dead
organic matter.
•
A food web shows all the feeding connections in the community.
(h) One particular energy flow path is called a food chain.
T
F
•
All species in the biosphere are connected through the global
food web.
(i) The position of a species in a food chain is its trophic
level.
T
F
•
Because of the complexity of food webs it is very difficult to predict
the alteration within an ecosystem if a species is lost or its population
undergoes a significant change.
(j) Herbivores occupy the first niche.
T
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(k) The niche of a species describes its position in a
pyramid of numbers.
T
F
(l) A pyramid of numbers tries to show the energy structure
of a community.
T
F
•
A pyramid of numbers attempts to show the energy structure of a
community in a particular ecosystem.
Check your answers to these questions on
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Protecting Ireland’s Biodiversity
d’s Biodiversity
What is ecology?
Saprophytes are a particular group of decomposers – they are
bacteria and fungi that feed on and decompose dead organic matter.
Saprophytes, besides being food for other organisms and clearing
detritus, also play a vital role in the recycling of mineral nutrients.
This lesson introduces the subject of ecology and the concept
of the ecosystem. We then go on to discuss habitats, the food
chain, and the pyramid of numbers. We will also learn about
Teagasc, the state agency providing environmental advice,
research and training.
The oak forest was the most widespread ecosystem in Ireland before
the arrival of humans. An oak forest ecosystem is twice as productive
as agricultural land. A hectare of oak forest has twice as much organic
matter remaining than a hectare of wheat has, after the plants have taken
what they need for their energy needs.
Biographical Notes
Examination Questions
Ecology is the study of the interactions between living organisms and of
their interactions
withHigher
their abiotic level
environment.
2004
/ 2003
Living organisms live in communities. A community is a group of species
(i)
Explain
following
terms
that
arearea.
used
ecology.plus
interacting
withthe
each
other and living
in the
same
Thein
community
(a) Biosphere,
(c) Consumer,
Producer,
the abiotic
environment(b)
withHabitat,
which it interacts
is called an(d)
ecosystem.
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Ernst Mayr
(e) Niche,
Ecosystem,
(g) Biodiversity.
The (f)
boundaries
between
ecosystems are not sharply defined but
gradual. This means that there can be considerable interchange between
ecosystems.
All saprophytes?
the ecosystems of our planet are connected to form a
(ii)
What are
giant ecosystem called the biosphere. The biosphere is the layer of living
Outline the role of saprophytes in the biosphere.
organisms that covers the earth extending in depth from 3 km below
ground to the highest level of the atmosphere.
����
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was one of the world’s leading biologists. He was born in Germany in
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1904.
One famous story is that he knew the names of all the birds in
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his locality
when he was 10 years old. He received his PhD at the age
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of 21. His work on birds led him
to develop new theories on evolution.
He is the originator of the concept of the biological species. He later
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worked ����
at Harvard University where he was Professor of Zoology. He
was a prolific author and published many scientific books and papers.
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He died in 2005
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2004:
State
Examinations Commission:
What is
the difference
Sample
betweenPaper
habitat and ecosystem?
What is the role of a speci
in a community called?
Eugene Odum
Ecosystem
refers
to a community
whereas
is to
restricted
to of
anenergy through
(9)
Answer
the following
questions
in habitat
relation
the flow
individual
species. The habitat is the place where the species is living
an ecosystem.
and to which the species has adapted. The species’ distribution may
be limited to only a small part of the ecosystem where a unique set of
(i) What
is the source of energy for the earth’s ecosystems?
conditions
occurs.
Adaptations
are the
‘solutions’
to environmental
‘problems’
and have
(ii) Name
process
that takes place
in plants
in arisen
which this
gradually as a result of evolution by natural selection. Human induced
converted
to
a
usable
form.
environmental changes to habitats or ecosystems often lead to the
extinction of species because they cannot tolerate the new conditions.
(iii) What substance do plants possess that allows them to
Therefore, the conservation of biodiversity demands the maintenance or
this conversion?
re-establishment
of habitats and ecosystems.
����
is one of the most influential ecologists of the 20th Century. He has
Every species in the community is said t
challenged many scientific assumptions about
the isworld
around to
us.
A niche
often considered
be the mann
�����������ecosystem ecology as a new integrative
He pioneered
science,
exploring
environment
in the struggle
to obtain its esse
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organism’s
most important
so all f
connections between pristine watersheds, plants,
animals,
climate resource,
and
food are vital parts of a species’ niche.
weather.
energy is
carry out
Fig.1 Energy flow in an ecosystem
Read about these and other famous
scientists
What
are the at
reasons for
www.sciencetechnolgyaction.com
constructing a pyramid of
What is a food chain?
A food chain is a sequence of species, each being the source of food for
The position of a species in a food chain is called its
(iv) Energy flows along food chains. In the food chain A B the
C;next
give
species.
Isn’t an
lifeexample
an energy-requiring
process?
level.
of each from the organisms
you found in atrophic
named
Yes it is.ecosystem.
The average human at rest uses 100 joules of energy every
second – this is equivalent to a 100 watt light bulb. We obtain most of
(v)energy
Is there
morerespiration
energy of
available
for organism
B orthisC?
our
by aerobic
‘food’. Plants
originally made
food during
photosynthesis when light energy was converted to chemical
answer.
energy. Therefore light is the energy for life.
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A pyramid of numbers attempts to discover
of an ecosystem as a bar chart by counting
each trophic level. The number of organism
pyramid. This is due to the large energy los
trophic level. As a result there is less energy
up the pyramid.
Explain your
(vi) A food web can be thought of as a number of interlinked ��������
food
chains. Using the named organisms A, B, C from (iv) above���������
and
three other named organisms; construct a food web that is found in
No. Food
made
by photosynthesis,
is also
a source
of organic materials
the
ecosystem
you have
studied.
(30)
Is food just a source of energy?
needed for the physical construction of living organisms. Approximately
90% of the food obtained by an organism is used as a fuel for energy and
(a)
pyramid
of numbers?
10%What
or lessis
is a
used
as building
material.
Producers
food byinmaking
it for themselves
from of
inorganic
(b)
What obtain
is thetheir
purpose
constructing
a pyramid
numbers?
materials, either by photosynthesis or chemosynthesis. Consumers obtain
theirDraw
food byafeeding
on organic
materials
other organisms.
(c)
pyramid
of numbers
formade
the by
named
ecosystem you
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100
5,000
Fig.2 Example of a food chain
Revise the Terms
Most species are members of more than one food chain in the community.
Amalgamating all the food chains into one flow chart produces a food web.
Did You Know?
The average human uses 100 joules of energy every second.
The consumers at the top of the pyramid do not represent the uppermost
end of the food chain. When they die, they are eaten by tiny, microscopic
organisms which serve as decomposers. When devoured by these
bacteria, the nutrients are returned to the soil to be recycled into yet
another food chain.
In 1988, Teagasc, the Agriculture and Food Development Authority, was
established as the national agency with overall responsibility for the
provision of research, training and advisory services to the agriculture
industry.
Second
106
5 x 109
Can you recall the meaning of these terms? Reviewing the
Relative Number of Organisms
The food web gives all the feeding connections in the community and
terminology
is aflows.
powerful
aid for
a clearer picture of the
complexity of energy
It also indicates
the recall and retention.
have
Animals
thatstudied.
feed on plants are called herbivores. Those that feed on other
delicate balance of nature because if one species is lost, or if its population
animals are carnivores. If their food consists of plants and animals, they
Ecology;
abioticPollution
environment;
community; species;
is changed dramatically,
all the otherorganism;
species will be affected.
can
are omnivores. If dead organisms are their food source they are called
be very destructive inecosystem;
ecosystems if it leads
to the elimination
of sensitive
biosphere;
habitat;
adapted; species distribution;
decomposers.
Omnivores
make
up
about
80%
of
each
ecosystem.
For further examples of past paper exam questionsspecies
check
or severe reduction of their populations.
out www.scienceandtechnology.com
Tertiary Co
evolution; natural selection; conservation; biodiversity; aerobic
respiration; food; plants; photosynthesis; chemical energy;
organic material; energy flow; producer; inorganic material;
chemosynthesis; consumer; feeding; animal; herbivores;
carnivores; omnivores; decomposers; saprophytes; bacteria;
fungi; mineral recycling; mineral nutrients; food chain; trophic
level, food web; balance of nature; pollution; population; niche;
resource; pyramid of numbers; pyramid of biomass; pyramid of
energy.
Check the Glossary of Terms for this lesson at
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F