Download Local environment

Topic 3
Local environment
Study notes
1.

The distribution, diversity and numbers of plants and animals found are
determined by abiotic and biotic factors.
Environment: An organisms surrounding.
Abiotic: Non-living things found in an environment.
Biotic: Living things found in an environment.
Habitat: where an organism lives.
Ecosystem: Is any environment where living organisms interact with each other.

Describe the differences between abiotic and biotic features of an
environment.
Abiotic features in an environment are the non-living things impact on the living
organisms. These may include trees, the weather and even the different types of soil.
Biotic features in an environment are the living things/organisms. These may include
fish, dingo’s and even humans.

Compare the abiotic characteristics of aquatic and terrestrial environments.
Features
Viscosity- Measure of
resistance.
Aquatic environment
Water has a high viscosity
rate. This makes it difficult
for organisms to move
through.
Terrestrial environment
The terrestrial environment
consists of air, which has a
very low viscosity rate.
Availability of gases.
There is 6% oxygen in
water. This makes it
impossible for humans to
breathe underwater.
There is 20% oxygen and
0.03% carbon dioxide in
the air.
Availability of water.
Water is not an issue in
aquatic environments.
However whether it is salt
or fresh water impacts
significantly on the biotic
features.
Water loss may be a
problem for organisms
especially those in arid
environments. Water will
impact significantly on the
biotic features of an arid
environment.
Availability of space.
May restrict animals
especially those which are
territorial. E.g. sharks and
sting rays.
May restrict numbers on
land for both plants and
animals, particularly those
which are territorial.
 Identify the factors determining the distribution and abundance of a species.
Distribution: Distribution of a species decides where it is found
Abundance: Abundance of a species determines how many of the species there is, in an
environment.
Factors determining the distribution and abundance of a species:
Abiotic Features:
Biotic Features:
 Amount of light
 Number of competitors
 Amount of rain fall
 Number of mates available.
 Temperature and seasonal
 Number of predators
variation
 Amount of food available for
animals and plants.
 Effect of topography
 Availability of shelter.
 Oxygen

Describe and explain the short and long term consequences on the eco-system
of the same species competing for the same resource.
Short term consequences:
Within the short term, an individual species usually show regular fluctuations in numbers,
because of the changing availability in food.
Long term consequences:
In the long term the distribution and abundance will reach a balance. In other words, the
number of organisms found there will be the number that can be supported by the
resources available.

Explain the need to use sampling techniques to make population estimates
when total counts cannot be made.
Plant Abundance:
When an organism is totally scattered over a huge area, it is quicker and easier to
randomly choose small representative areas of vegetation called quadrates and count or
estimate the numbers in them.
Animal Abundance:
Whilst determining animal abundance it is easier to use the capture/recapture method.
This technique consists of capturing an animal, tagging the animal and releasing the
animal.
 First hand investigation of capture/recapture method.
Aim: To model the capture/recapture method.
Method: 1. Collect two sets of ten, colored beads.
2. Place 20 beads in one container
3. Pick out 10 of the 20 beads.
4. Record the number of each colored bead into two columns, Black beads and
blue beads.
5. Repeat this experiment 10 times to ensure reliability.
Results: Total of 48 blue beads and 52 black beads.
Conclusion: this is a very accurate form of determining the abundance of species.

Identify data sources, gather and process information from first-hand and
secondary sources to construct food webs and food chains to illustrate the
flow of matter energy and use the evidence available to discuss the
relationships between different organisms in the ecosystem.

Describe the flow of matter through a natural ecosystem using the water,
carbon/oxygen and nitrogen cycle.
The water cycle:
1. Water from the earths atmosphere falls onto the fall.
2. Water falling will be caught/deposited in catchments areas.
3. Water will also flow to lakes, rivers or dams.
4. Living organisms will take in the water, or some of the water will transpire back
into the atmosphere.
5. Water in oceans, lakes will evaporate, and be rained down again in the future.
Co2, oxygen cycle:
1. Co2 is absorbed by plants for photosynthesis.
2. Carbon compounds move through food chains and food webs.
3. living organisms use oxygen and return co2
4. When things die, their bodies are broken down and more co2 is produced.
5. When burning fossil fuels, Co2 is released, and taken in by plants, and the process
repeats.
Nitrogen Cycle:
1. Bacteria and Cynobacterium convert nitrogen into useable forms of energy such
as nitrates in the soil. Plants incorporate nitrogen into their tissues as proteins. It is
returned to the soil when the plant dies. Denitrifying in the soil completes the
process by returning nitrogen into the air.
 Identify uses of energy in organisms:
Uses of energy include:
1. Use energy in order to grow.
2. Repair and maintain any damaged cells.
3. Active transport of materials across all cell membranes.
4. Functioning of special cells.
Food
Chain
Food
Web
 Describe the flow of energy through a natural ecosystem.
The flow of energy from one living thing t another can be seen by the following:
Green plant  Plant eater  Animal eater (begins with a producer, ends with carnivore)
To show more complex feeding patterns and flow of energy, a food web is shown.
3.

Process secondary information to identify OH&S issues to identify potential
sources of physical, chemical and biological risk, before undertaking an
investigation of a local terrestrial or aquatic environment.

Plan, choose equipment and perform a field study of a local terrestrial or
aquatic environment to:
1. Measure abiotic variables in the ecosystem being studied using
appropriate instruments and where possible combine with recorded
values and relate this to the distribution of organisms.
2. Estimate the size of a plant and an animal population in the ecosystem
using transects and or random quadrates techniques.
3. Gather data to describe the distribution of the plant and animal
species whose abundance has been estimated.
4. Use available evidence to describe observed trophic interactions
between two plant and two animal species found in the area.

Process and analyze information to prepare a report on the field study
undertaken using an appropriate styling report.

Examine trends in population sizes for some plat and animal species with an
ecosystem.
Trends in population sizes, their rise and falls can be directly observed when studying
ecosystems over a period of time. Generally, trends in population may be because of,
number of predators, number of produces, number of hosts and abiotic features.
 Outline factors that effect numbers in predator and prey populations.
When there are large numbers of prey available, the number of predators will
undoubtedly increase. However when the food becomes scarce, the number of predators
will decrease. This is known as the predator-prey cycle.
 Importance of decomposers.
Decomposers have an important role to play in the local environment because they
make the materials (nitrates) provided by decomposition available to plants for uses of
energy. They all recycle dead animals, and re-establish the food cycle.

Trophic interactions between organisms in the local ecosystems using food
chains, food webs and pyramids of biomass and energy where appropriate.
Energy pyramid:
3rd order
Carnivores
2nd order
Carnivores
1st order
Carnivore
Herbivore
The amount of energy
can be shown by an
energy pyramid. It is
evident that after each
consumer, the amount of
energy passed to the
next consumer
decreases.
Producers
Biomass Pyramid:
Carnivore
Herbivore
Producer
The biomass pyramid
shows the amount of
matter in an organism at
each trophic level.

Identify and describe adaptations of plants and animals from the local
ecosystem:
Adaptation: an adaptation may be behavioral, physiological and structural.
Plant adaptations:
- Small root hairs. (structural)
- Waxy cuticle. (Structural)
- Leaves which hang upright in summer. (behavioral)
- Leaves with small surface area. (Structural)
Animal adaptations:
- Burrowing underground in extreme temperatures. (behavioral)
- Lying in shade in hot temps (behavioral)
- Reduce/minimize activity levels (behavioral)
 Describe the effects of human impacts on the environment:
Effects of human impact on the environment include;
- Land Clearing
- Urbanization: Removing trees to place buildings.
- Pollution, this may be land, air or sea.
- Dumping wastes
- Eutrophication: When mineral nutrients enter the inland waterways such as rivers,
lakes and dams the effect is the increased levels of nitrogen. This increases plant
growth. Increased plant growth, promotes plants which need the same resources
to compete against each other.
 Different views in society:
In society, different people have different perspectives. E.g. if an area of bush land
were to be cleared, conservationists would want to keep the area free from occupation,
developers would want to build a structure i.e. mall, and farmers would want to grow
crops on it.

Some criteria from the local government concerning zoning of the land and
uses of the land e.g. domestic housing, units, schools and public transport.
In Australia, the use of land is regulated by the law. They come under the environmental
planning and assessment act 1979.
People must submit a plan to the local council when they wish to develop the land for
various purposes. Each council as a local environment plan and development control
plan, which regulates the notion of zoning.
Development standards are requirements that must be met in specific types of land
development.