Transcript habitat - Glow Blogs

Section 5
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Groups of living and non-living things (the
environment they live in) make up an
ecosystem
Some ecosystems include forests, ponds,
and streams
There are lots of different components that
make up an ecosystem. These are the
communities, habitats and populations
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A habitat is a place where an organism lives
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E.g. A fishes' habitat could be pond water
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A habitat is a component of an ecosystem
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A population is a group of the same species
that live in a habitat
A community is the sum total of all the
populations of plants, animals and microorganisms living together in an ecosystem
This entire picture represents a
pond ecosystem.
The pond is a habitat
All the organisms of the pond
make up the pond community
All the organisms
of one kind make
up a population
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All living things gain
energy from the sun
Green plants can
photosynthesise and
therefore make their own
food so are called
producers
Animals and non-green
plants have to consume
other animals and plants
to gain energy to stay
alive and grow. They are
known as consumers
Produces
its own
food to
gain
energy
Consumes
other
animals to
gain
energy
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Among animals, there are different types of
consumer:
Ones that eat only plants – HERBIVORES
Ones that eat only other animals –
CARNIVORES
Ones that eat both plants and animals OMNIVORES
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An animal which hunts another animal for its
food is called a predator
The hunted animal is called the prey
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An important groups of organisms in an ecosystem are
decomposers because they break down the dead
remains of animals and plants.
Decomposers play an important role in recycling of
nutrients
Fungi and bacteria are important in the decomposition
process
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A niche is the role an organism plays within a
habitat
E.g. The niche of a decomposer is to recycle
nutrients from dead organisms, the niche of a
green plant is to produce food for other
organisms as well as themselves
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The niche of a species is its role in its habitat
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Make a table with the headings “Organism
from Loch Ecosystem” and “Description of
Niche”
Using the diagram on the previous slide, write
down the organism and describe its niche in
the ecosystem
Organism from Loch
Ecosystem
Description of Niche
Minute Green Algae
Microscopic floating producer
Bacteria
Decomposer
Lice
Parasite feeding on fish scales
Water flea
Small swimming herbivore
Osprey
fish-eating bird of prey
Brown Trout
Medium-sized swimming carnivore
Pondweed
Rooted underwater producer
Pike
Large predatory swimming top
carnivore
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When an organism eats
another organism,
energy is being
transferred
This transfer of energy
can be represented as
a food chain
The arrows indicate the
direction of energy
flow
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Food chains always start with producers
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A herbivore which eats plants is known as a
primary consumer in a food chain
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An animal which eats the primary consumer
is known as a secondary consumer and so
on
Remember, the arrows indicate that energy
is being transferred from one organism to
the next
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http://www.bbc.co.uk/schools/ks2bitesize/s
cience/living_things/food_chains/play.shtml
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Food chains are linked together in a complex way
to form food webs
Under natural conditions, an ecosystem really
contains many inter-connecting food chains
1.
What is a producer?
2.
What is a herbivore?
3.
What is a secondary consumer?
4.
What is meant by the terms predator and prey?
5.
What might happen to the population of rabbits
in a food chain if foxes were removed?
6.
What do arrows in a food chain represent?
1.
A producers is a green plant that makes its own food by
photosynthesis
2.
A herbivore is an animal that only eats plants
3.
A secondary consumer is an animal that eats primary
consumers
4.
A predator is an animal that kills other animals for food. A
prey is an animal that is hunted for food.
5.
If foxes were removed, the population of rabbits would
increase (because there are no predators)
6.
Arrows in a food chain indicate the direction of energy flow
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As energy flows through a food chain or web,
energy is lost at every stage
Energy is lost in a number of ways:
◦ Movement of an organism will generate heat energy
which is lost
◦ Expelling wastes e.g. Faeces which contain
undigested food
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Only 10% of the energy in a living organism is
passed on to the next animal in a food chain
because of these reasons
1. The caterpillar eats the leaf
2. Some of
the energy in
the leaf is lost
in waste which
passes
through the
digestive
system of the
caterpillar
3. Some of the
energy is lost
as heat as the
caterpillar
moves about
4. Only a small proportion of the
energy is stored in the body of the
caterpillar. This is the only energy
available to the animal that eats it
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Loss of energy from a food chain usually means
that the organisms nearer the top of the food chain
are fewer because there is less energy to support a
large population
A pyramid of numbers is a diagram which
represents the number of organisms at each stage
in a food chain as a horizontal bar in pyramidshaped bar chart
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Pyramids of Numbers
do not always have the
same shape
One organism can have
more energy than 10
organisms at the next
level
Woodland
Grassland
Habitat
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e.g. ONE oak tree has
more energy than 100
caterpillars
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A pyramid of biomass is a diagram which
represents the total mass of organisms at
each stage in a food chain as a horizontal
bar in a pyramid-shaped bar chart
Remember that biomass is not always
related to the number of organisms!
There maybe one organism with a large
mass that can pass on energy to a large
number of consumers
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Pyramids of Energy
◦ Diagrams that represent the quantity of energy at
each stage in a food chain as a horizontal bar in a
pyramid-shaped bar chart
Secondary
Consumer
Primary
consumer
Producer
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As energy is always lost at each stage, so the
shape of a pyramid of energy is always
maintained
1.
Which of the pyramids of numbers shown is the
best representation of a food chain that starts
with an oak tree and ends with hawk?
A
2.
3.
B
C
Why are there rarely more than four or five links
in a food chain?
Describe two ways in which energy is lost from a
food chain
1.
2.
3.
B
Because so much energy is lost at each step
there is not enough to sustain more links
As heat and as waste such as faeces and
urine
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Organisms that belong to the same species
can breed with one another to produce fertile
offspring
This means that when offspring reach sexual
maturity, they will be able to produce more
offspring themselves
Animals belonging to the same species can
interbreed to produce fertile offspring
Animals that do not belong to the same species
produce infertile offspring
X
=
X
=
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Biodiversity means the variety of species
present in an ecosystem’s community
There can be biodiversity between members
of the same species and between different
species
Bio = living, Diversity = differences
Biodiversity = differences in living things
Which of these ecosystems is stable and which is not?
Give a reason for your answer.
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Stable ecosystems contain a variety of species
and can last a very long time
If there are only a few species within an
ecosystem, any change in population will
severely affect other populations
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An adaptation is a feature of an organism
which enables it to survive successfully in its
habitat
The adaptations of an organism can dictate
where that organism lives and what it eats in
the case of animals
Two examples of organisms that have
adapted to suit their environments are a type
of bird called the finch and cactus plants
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Charles Darwin visited the Galapagos Islands and recorded
his findings about the different species of finch.
He found that:
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On each Island, the landscape and food source for the finches
was different
The finches had adapted to their environment by changing
their body size and beak shape so that they could eat food
and survive
This resulted in 13 different species being formed over
millions of years
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Adaptation of nectar-eating Ground Finch – it has a
long, thin beak to get nectar from flowers
The distribution of Woodpecker Finches is
restricted to trees as this is were its food source is
The seed-eating Ground Finch cannot survive on
an island which has few trees and shrubs because
its beak is adapted to eat this type of food only
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In your notebook, write a short report to summarise
your finding from the experiment. You can work in a
group or with a partner if you wish.
Here is some information that you may want to think
about:
◦ Describe how different “beak” types are suited to
different food sources and say why.
◦ Which “beak” types were the most successful and why?
◦ Which “beak” types were the least successful and why?
◦ What will happen to the populations of the most and
least successful beak types? Again, say why this is.
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The desert is a hot, dry environment where water is in limited
supply
Cactus plants have adapted to this environment by employing
the following mechanisms:
◦ Leaves have been reduced to spines to limit water loss via
evaporation because of the smaller surface area
◦ Root network is extensive to absorb water when it does rain
◦ The green stem of the plant has a thick, waxy cuticle to
reduce water loss
◦ The stems and leaves are succulent and fleshy to store
water
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Animals that graze on plant species help to
keep ones that show vigorous growth in
check (this means one species of plant will
not take over all the others)
If grazing is at a very high or low intensity,
this can affect biodiversity as some plant
species may disappear or one species may
overtake the rest
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Sulphur Dioxide
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Burning fossil fuels and emissions from car exhausts
release sulphur dioxide into the atmosphere which can
damage many types of plants
Acid Rain
◦ When acid rain falls, it lowers the pH of soil and
rivers and organisms die as a result
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http://www.yenka.com/freecontent/item.acti
on?quick=v4#
When water used as a coolant, it is returned
to the natural environment at a higher
temperature and the change in temperature
impacts organisms by
◦ (a) decreasing oxygen supply
◦ (b) affecting ecosystem composition
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Deforestation
◦ Huge forests of South America are being cut down
at an alarming rate. This reduces biodiversity and
has many other impacts of Earth, including climate
change
Deforestation in the Amazon
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Where resources are limited, animals compete with one
another, even members of the same species
Animals will compete for:
◦ Food
◦ Water
◦ Shelter
◦ Mates
Evolution ensures that only the best adapted animals (and
plants) will go on to reproduce and pass on these desired
traits
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Plants compete for the following resources:
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Water
Light
Space to grow
Nutrients for strength and proper development
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All animals, no matter how simple, show
adaptations to their environment. This is normally
a response that ensures well-being and survival
Changes in the surrounding environment to which
an organism is sensitive to can be described as an
environmental stimulus
The response by the organism to the stimulus is a
behavioural response
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When in dry environments, their rate of
movement will increase
When they enter a damp environment their
rate of movement slows down
This response ensures that they do not dry
out and die
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As the day length decreases in the autumn,
swallows respond by migrating south to
Africa
This is because the insects that swallows feed
on are more readily available in Africa in the
winter
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Found attached to rock surfaces in rock pool
They have tentacles which pull things towards
their bodies if these objects touch them
Mechanism for catching prey
http://video.google.com/videoplay?docid=9154988096852919253
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Responses to the environment are often very
useful and offer a survival advantage
E.g. avoids predators, catching prey, ensuring
favourable conditions for biological processes
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Found beneath leaf litter, stones and dead bark
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Damp conditions protect from predators and
from drying out
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Woodlice are studied because of simple
behavioural patterns and apparatus used
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Collect 10 woodlice per group
Introduce woodlice into the choice chamber through
the hole - gently!
After 10 minutes, record how many woodlice are on
each side of the choice chamber (light or dark side)
Using class results, work out a class average for the
number of woodlice on each side of the chamber
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In your experiments, it is important that more
than one woodlouse was used to ensure that
the results are reliable
If the humidity and light were both changed
in each chamber then the results of an
experiment would be invalid as more than
one factor is being changed so you cannot
reliably say what has caused the woodlice to
move
A choice chamber is set up with one side moist and the other
side dry. Ten woodlice are placed in the choice chamber and
left for 1 hour undisturbed.
1.
Where should the woodlice be placed?
2.
Why are ten woodlice used rather than one?
3.
4.
5.
State two factors that should be kept constant during the
investigation
Where would you expert to find the woodlice at the end of the
investigation?
What advantage is it to the woodlice to behave in this way?
1.
In the middle or equal number on each side
2.
To improve reliability
3.
Temperature and light intensity
4.
On the moist side
5.
They reduce water loss from their bodies