The Kelso High School
Biology
Environment
Name……………………..... Class………..
Keep this booklet safe – you will need it for revision.
Environment
Use this table as a checklist for your revision.
= core
= challenge
Understood
and learnt
Level
Need to do
more work
Need to get help
- see my teacher.
You need to be able to……
Give the definitions for ecosystem, habitat, population
and community.
Identify 2 abiotic and 2 biotic factors
Give an example of a technique which could be used
to measure an abiotic factor and describe its use.
Identify a possible source of error of that technique
and explain how it might be avoided.
State the effect of one abiotic factor on the distribution
of organisms.
Explain how abiotic factor affect the distribution of
organisms.
Identify organisms using branching and paired
statement keys.
Construct branching and paired statement keys.
Give an example of a technique which could be used
for sampling organisms and describe its use.
Identify a possible source of error of that technique
and explain how it might be avoided.
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Give the definitions for producer, consumer,
herbivore, carnivore, omnivore, primary consumer,
secondary consumer.
Give an example of a food chain and a food web.
State that the arrows in a food chain indicate the
direction of energy flow.
State 2 ways in which energy can be lost from a food
chain.
Explain the effects of removing one species on the
remaining organisms in a food web.
State that the growth of a population depends on the
birth and death rate.
Describe and explain the growth curve of a population
under ideal conditions.
State 3 factors which can limit the growth of a
population.
State that competition occurs when organisms have a
need for the same resources.
Describe some effects of competition.
Date of ‘Environment’ End of Unit Assessment:
………………………………….
Remember, in addition to testing your knowledge the assessment will include
problem solving questions, eg graph drawing, calculations, etc.
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Ecosystems
Term
Definition
Ecosystem
Habitat
Population
Community
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Example
Factors Affecting Ecosystems
Many things can affect ecosystems.
Living things which can affect ecosystems are called ________________
factors. These include:

_____________________________________

_____________________________________

_____________________________________
Non-living things which can affect ecosystems are called ________________
factors. These include:

______________________________________

______________________________________

______________________________________

______________________________________
It is useful to measure abiotic factors and various pieces of equipment can be
used to do this. To make sure that your measurements are reliable the
equipment must be used properly.
Abiotic
Factor
Equipment
Used
Sources
of
Error
Light
Intensity
Moisture
Meter
- probe not left long
enough to monitor the
moisture level.
- probe not wiped after
each sample.
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Ways in Which
Error is
Minimised
- don’t stand in front of
the sensor.
Identifying Organisms
If you are studying the populations and communities in ecosystems you need
to be able to identify the plants and animals that are there. To do this you can
use a key.
There are two types of key:

_______________________________________

________________________________________
A Branching Key:
Leaves
Prickles
(HOLLY)
No Prickles
Jaggy Edge
(ELM)
Smooth Edge
No Lobes
(BEECH)
Lobes
(OAK)
A Paired Statement Key:
1. Leave with prickles………………………HOLLY
Leave without prickles…………………..Go to 2.
2. Jaggy edge………………………………..ELM
Smooth edge……………………………..Go to 3.
3. Lobes……………………………………...OAK
No lobes…………………………………...BEECH
Use the keys to identify the following leaves:
______________
____________________
_______________
_________________
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Sampling Organisms
If you are studying plants and animals in an ecosystem you may need to find
ways of capturing and counting them. There are many different ways to do
this depending on the animal or plant you are studying.
A pitfall trap is used to collect animals that live on the soil surface and
amongst leaf litter.
________________
____________
_________________
Avoiding Errors When Using a Pitfall Trap

_____________________ pitfall traps should be set up to give reliable
results.

The opening of the trap should be disguised by a ____________so that
trapped animals are not seen and eaten by predators.

A preservative liquid, eg _________________ is put in the bottom of
the trap to humanely kill and preserve the animals.
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It is unlikely that you would be able to count all of the plants and animals in an
ecosystem because this would take too long. Instead, small samples which
represent the whole ecosystem are taken
Plants are often sampled in this way using _________________________.
This is a square of a known area which is randomly placed on the site being
studied. The plants inside the quadrat are identified and counted. From this
information the estimate of the number of a certain plant can be calculated.
____________
_________
___________
Avoiding Errors When Using a Quadrat

Make the results more ______________ by using a bigger number of
quadrats.

Place the quadrats at _______________ over the area being studied,
don’t choose where to place it.

Make a rule to decide what to do with plants that fall partly in or out of
the quadrat, eg more than half the plant in the quadrat counts, more
than half out the quadrat doesn’t.
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Energy Flow Between Organisms
There are several terms that can be used to describe the way organisms
obtain their energy.
Term
Definition
Example
An organism that can produce its own
food. Usually a green plant that
Producer
produces its own food using energy
from the sun by the process of
photosynthesis.
Any organism that cannot produce its
own food, instead they eat other
organisms to get their energy.
Herbivore
(or primary
consumer)
Fox
Tiger
An animal that only eats both plants and
animals to get their energy.
The way in which energy passes from plants to animals and then to other
animals can be shown by a food chain.
There are two rules when you make your own food chains:

All food chains start with a ___________________

You must show the ________________ in a food chain. The arrows
in a food chain go from food to feeder and represent the direction of
energy flow.
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As energy is passed along a food chain each of the organisms uses some of it
for its own needs, eg moving, keeping warm, etc. This means that energy is
lost at each link in the food chain and the only energy that can be passed to
the next link in the food chain is that which is part of the body of the organism
itself.
Approximately _________% is used by the organism and not available to the
next link in the food chain, so only about ________% of the energy can be
passed on.
Most animals eat more than one kind of food and so in any ecosystem food
chains connect to form a food web.
All food webs are delicately balanced. The removal of one organism from the
food web can have a serious effect on others.
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Population Growth
The size of most populations tends to stay roughly the same. The size of a
population stays the same as long as the birth rate is the same as the death
rate.
1. Little or no increase as
the population starts to
reproduce.
2. Rapid population
increase.
3. No more increase as
population numbers are
checked by something.
Time
In most populations there is something which prevents a population explosion.
Limiting factors are things that prevent a
population from growing any larger. For
example, 10 rabbits may live in a habitat
that has enough water space to support
20 rabbits, but if there is only enough
food for ten rabbits, the population will
not grow any larger. In this example,
food is the limiting factor.
Food is not the only factor that may limit
population growth. For example, there
may be enough food to support a
thousand birds in a certain area, but only
suitable nesting sites for one hundred.
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Competition
If organisms use the same resources the competition will occur.
Animals compete for:
Plants compete for:
___________________
___________________
___________________
___________________
___________________
___________________
___________________
___________________
When competition occurs some organisms will be more successful than
others. These organisms will be more likely to survive.
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