Transcript Ecosystems

Ecosystems
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Habitats
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What is an ecosystem?
The environment is made of many different types of
ecosystems, such as seashores, forests, lakes and deserts.
Each ecosystem can be divided into a:
 habitat – the non-living part, i.e. the physical area in
which organisms live
 community – the living part, i.e. all the different organisms
living in that particular habitat.
Each community is made up of many different populations.
A population is all the members of a particular species
living in one habitat – for example, the population of red
squirrels in an oak wood.
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What is a habitat?
What makes a habitat?
A habitat has all of the
things that an organism
needs to survive, such as
the right amounts of
oxygen, water, light and
shelter.
How would you describe
your habitat?
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Different types of habitats
How are these habitats similar and how are they different?
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Which land habitat?
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Which water habitat?
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Sampling in a habitat
Ecosystems are constantly changing. In order to tell how the
populations within a community change over time, you first
need to establish how many organisms there actually are.
It would be impossible to count all the individual organisms
in a habitat by hand. Instead we can count just a sample
from a small area and multiply this by the total area of the
habitat. This gives an estimate of the total number of the
population.
Common sampling methods include:
 quadrat
 line transect
 belt transect
 trapping.
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Sampling a population
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Adaptations
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What are adaptations?
Each type of organism has special features that help it
to survive in its particular habitat. These special features
are called adaptations.
For example, you have plenty of
adaptations to survive in your
habitat. Your fingers are an
excellent adaptation – without the
ability to grip, you would not be
able to do all that schoolwork!
Some adaptations are obvious
while others are not so obvious.
Can you think of any other
adaptations that you have?
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Adaptations in different habitats
These organisms are all adapted to their environments in
very different ways.
How are they specially adapted to survive?
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Adaptations in similar habitats
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What are adaptations for?
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A new species…
Scientists have discovered this strange new species on a
small island off the coast of Argentina.
The scientists want you to help them describe:
 where this animal lives (land, water or air)
 what it eats and how it eats
 how it breathes
 how it moves
 what they should call it.
As the organism is adapted to its environment, you should
be able to use the way it looks to answer all of these
questions. Don’t forget to give your organism a name!
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Daily adaptations
Many features of the environment change on a daily basis,
such as the temperature and the amount of light.
For example, many flowers open
their petals during the day to
catch the sun and close them at
night to protect against the early
morning frost.
Organisms are adapted to
the type of habitat they live in
and also to the daily changes
that occur in that habitat.
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Yearly adaptations
The environment also changes on a yearly basis with the
seasons. This may bring about changes in light and
temperature, but also in the availability of food and water.
Organisms have to adapt to
these yearly changes; they
have come up with many
different ways to achieve this.
For example, some animals
hibernate over winter to deal
with food shortages.
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Daily or yearly?
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Effects of environmental change
Animals are adapted to suit their environment, helping them
survive and reproduce. However if the environment changes
they may no longer have this advantage.
A change in environment can cause extinction. Extinction
is when the last individual of a species dies.
When a species is at
risk of extinction, it is
endangered. Over
1,100 animal species
and over 700 plant
species are classed
as endangered or
threatened.
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Why is important to conserve species?
Extinction can cause a decrease in biodiversity. Biodiversity
is the number and variety of organisms found in an area.
Conserving biodiversity is important as every living thing plays
a vital role in an ecosystem. If one species becomes extinct
this can have a huge impact on the rest of the community.
Extinction can also decrease the
resources available to humans. For
example, some medicines are made
from plants – if a plant species
becomes extinct its unique chemicals
are no longer available to us.
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Biodiversity
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Humans impact on environment
Extinction can occur naturally, however human impact on
the environment can also cause species to die out.
Human activity can cause
damage to the environment in
several different ways:
 destruction of natural habitats
 over-hunting
 climate change
 pollution.
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Deforestation
Humans often destroy forest habitats to make room
for housing or industry. This is called deforestation.
If a woodland habitat is destroyed some animals may no
longer have resources they need, e.g. food and shelter.
Species that aren’t able to survive outside of their natural
environment may become endangered.
In Borneo, southeast Asia, forests are slowly being
removed to make way for other crops.
1950
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2000
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Environmental effects of climate change
Human activity may be causing a change in the world’s climate.
The production of carbon dioxide, and other heat-trapping
gases from the burning of fossil fuels may be causing the
earth’s climate to change. This is called the greenhouse
effect.
This change in the earth’s
climate could result in:

higher global temperatures

sea level rising

a different geographical
distribution of rain fall.
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How could change affect ecosystems?
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The effect of change on polar bears
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Extinction due to climate change
If climate change causes an impact on habitats and
ecosystems this could result in more species becoming
extinct.
It is thought that
20–30% of species
are likely to be at
risk of extinction if
the global average
temperature rises
by 1.5–2.5 °C
beyond 1990 levels.
What evidence is there that global temperatures are rising?
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Evidence for global temperature change
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Glossary
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Anagrams
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Multiple-choice
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