1. A Local Ecosystem

2. Ecosystems – What do we already know?
What is an ecosystem?
Create an ecosystems mindmap

3. Ecosystems revision – Important definitions
Ecology
Species
Population
Community
Ecosystem
Habitat
Environment
Biome

4. Ecology
Ecology is the study of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment

5. Species - Groups of similar individuals that can reproduce fertile offspring (e.g. kookaburra, snow gum)
Population - Group of organisms of the same species living in the same area at a particular time
Community - Groups of different populations in an area or habitat

6. Community and population
A community can be defined as the set of
interacting organisms within an ecosystem. A
population is a group
of individuals of the
same species
living in the
same area.

8. Environment - Both living (biotic) and non-living (abiotic) surroundings of an organism
Habitat – the place where an organism lives

9. Ecosystem - A community together with its environment
Ecosystem - A community together with its environment. Any environment containing organisms interacting with each other and the non-living parts of the environment (e.g. rainforest, freshwater pond)
Biome - Large regional system characterised by major vegetation type (e.g. desert); region of earth with similar ecosystems grouped together

10. The World’s Biomes

11. Levels of Organisation

12. Levels of Organisation

13. Schematic diagram representing the biosphere

14. Abiotic features of the environment
Abiotic features are the non-living
components of the environment. They
include,
Physical features: temperature, rainfall, wind, light intensity, humidity, soil type, water, landform
Chemical features: pH of soil or water, salinity, availability of gases

15. Biotic features of the environment
Biotic features are the living components of
the environment. This includes:
Plants
Animals
Micro-organisms

16. Aquatic environments Environments can be classified as aquatic (water)
or terrestrial (land). Aquatic
environments can be either
freshwater or marine
(saltwater).

17. Terrestrial Environments
Terrestrial environments are environments on land which covers around 35% of the Earth’s surface.
Differences in the climate and topography of the land have produced many different terrestrial environments.

18. Terrestrial environments
Terrestrial environments are found in
different climates and range from deserts,
grasslands
and rainforests to
mountain regions.

19. Aquatic v’s terrestrial
Organisms living in aquatic and terrestrial
environments have to survive different abiotic
conditions. When comparing the difference
between the two it is necessary to look at
features such as: buoyancy, pressure,
temperature, availability of gases, light
penetration and viscosity.

20. Dot Point 8.2.1a
Compare the abiotic characteristics of aquatic and terrestrial environments:

21. Abiotic Characteristics of Aquatic and Terrestrial Environments
Aquatic Environment
Terrestrial Environment
Buoyancy (is the amount of support experienced by an object immersed in a liquid or gas)
Chemical: Carbon Dioxide
Chemical: Ions
Chemical: Oxygen
Chemical: Water
Light
Pressure
Temperature
Viscosity (measure of a mediums resistance to an object moving through it)

22. Dot Point 8.2.1b
Identify factors determining the distribution and abundance of a species in each environment:

23. Distribution Distribution refers to the region where an
organism is found.
Distribution of rabbits in Australia Adapted from: Clarke GM et al (2000). Environmental Pest Species in Australia. Internal report, Department of the Environment and Heritage, Canberra.

24. Distribution It is usually uneven throughout the ecosystem
Organisms are found where abiotic and biotic factors favour them
Organisms are distributed where:
 Survival rate is high
 Predation is low
 Requirements for survival are met

25. Abundance
Abundance is the number of individuals of the same species within an area.
Not the same throughout environment
Changes over time:
 Increases due to births and immigration
 Decreases due to deaths and emigration

26. Abiotic Factors Affecting Distribution and Abundance
Light
Strength of wind
Rainfall
Temperature variations
Topography
Tides, currents and waves
Water (amount, salinity, pH)
Substrate
Space and shelter
Oxygen

27. Biotic Factors Affecting Distribution and Abundance
Availability of food
Number of competitors
Number of mates available
Number of predators
Number and variety of disease causing organisms

28. Measuring Population Distribution and Abundance
A population is a group of similar organisms living in a given area as a time
Populations can never be 100% accurately counted. Why?
Populations are estimated using sampling techniques. These make an estimate, which is roughly accurate of the population.

29. Measuring Distribution Transect Measuring Abundance Plants – Quadrats
Process and analyse information obtained from a variety of sampling studies to justify the use of different sampling techniques to make population estimates when total counts cannot be performed:
Measuring Distribution
Transect
Measuring Abundance
Plants – Quadrats
Animals – Capture-Recapture

30. Transects The distribution of plants can be determined
by marking out a straight line across an area,
noting the types of plants present, and plotting
their position along this line on a diagram. This
indicates the distribution of plants along a cross-
section of the ecosystem. This cross-section is
called a transect.

31. Transects
Georges River Environmental Education Centre

32. Abundance Abundance is the number of individuals of the
same species within an area. Abundance is
usually found by taking
small samples of a
community and using
the data to estimate the
population in the
ecosystem as a whole.

33. Quadrats The abundance of a plant species is often found
by marking out quadrats. Individuals within the
quadrats are counted and the average number
per area (density) is calculated. This information
can then be used to estimate the abundance in
the whole ecosystem. The more quadrats used,
the more accurate the estimate.

34. Quadrats

35. Capture – mark - recapture
This method of sampling involves:
catching a number of individuals of a species
marking or tagging them
releasing them again
at a later time catching another group and counting the number of tagged individuals among them
This method is useful for mobile populations.

36. Trends in population estimates
Variable that can influence population size over
time include,
Birth rate
Death rate
Migration rate
Environmental factors such as availability of food, shelter and water, presence of predators

37. Population Trends

38. Population growth
Growth is initial slow as the species adjust to the environment and establishes reproductive patterns
The population becomes established and growth is more rapid
Environmental factors such as competition for the same resources causes the curve to level of (reach equilibrium)

40. Predator – Prey Relationships

41. Predation
A detrimental relationship in which one organism kills and eats another one

42. Identify examples of allelopathy, parasitism, mutualism and commensalism in an ecosystem and the role of organisms in each type of relationship:

43. Allelopathy
This is the production by a plant of specific chemicals (allelo-chemicals) which inhibit the growth of other plants around it
Example: the Casuarina. Its leaves contain allelo-chemicals, so as they dropped to the floor, they released the chemicals, preventing the growth of other plants in the area

44. Parasitism
This is a relationship between two organisms where one benefits at the expense of the other organism
Example: the pimple wasp. It lays its eggs on the leaves of the mangrove. The larvae eat through the leave when they hatch and the leaf is damaged

45. Mutualism
A relationship between two organisms where both of them benefit
Example: lichen. This consists of a fungus and an alga joined together. The fungi provides structure and the alga provides food

46. Commensalism
A relationship between 2 organisms where only one benefits, and the other get no harm and no benefit
Example: the golden orb-weaving spider and the dewdrop spider. The weaving spider makes a web, and catches its prey with it. It leaves scraps behind. The dewdrop spider eats the leftovers.

47. Competition for resources
Competition is a relationship in which two
organisms compete for a limited resource.
In the short term this results in a decrease in the
abundance of one of the species. In the long
term it can result in extinction of the less
successful species.

48. Competition for resources.
Competition is one pressure that influences the
evolution of organisms. For example,
competition is one of the factors that results in
organisms adapting to occupy distinct niches.

49. Photosynthesis The initial source of energy in an ecosystem is
light from the sun. Some of the light absorbed by
plants is converted through photosynthesis into
chemical energy in the form of carbohydrates
such as glucose. Photosynthesis is summarised
as:
light
carbon dioxide + water glucose + oxygen
REACTANTS ENERGY PRODUCTS
SOURCE

50. Respiration Some of the glucose produced by
photosynthesis is broken down during the
process of respiration. Respiration can be
summarised as follows:
Glucose + oxygen water + carbon + energy
dioxide
The energy produced during respiration is then
used for cellular processes.

51. Energy transfer in an ecosystem
Light energy
Converted into carbohydrates
Chlorophyll
Photosynthesis
Glucose
Transported through the plant
Respiration
Energy for cell processes

53. Uses of energy by organisms
Living organisms need a constant supply of
energy to maintain cellular activities and stay
alive. In ecosystems the initial source of energy
is light from the sun. This is used by plants
during photosynthesis to produce carbohydrates.
Organisms (i.e. plants) that can manufacture their
own food from inorganic materials are called
autotrophs.

54. Producers and consumers
Green plants provide the entire input of energy
to an ecosystem and are called producers. When
animals (herbivores) eat plants, the
carbohydrates stored in plants are converted
back into glucose. The glucose is broken down
during respiration to provide the animal’s
energy requirements. Similarly, when carnivores
eat other animals, this chemical energy is
passed on.

55. Energy transfer in ecosystems
Eaten by
animal
Plant
Converted into other substances
Carbohydrates digested to glucose
Respiration
Energy for animal cellular process

56. Food chains and webs Food chains show the flow of energy through
ecosystems.
FIRST ORDER CONSUMER
SECOND ORDER CONSUMER
PRODUCER
wallaby
dingo
grass

57. Trophic levels Animals are consumers. An organism that feeds
on plants is a first-order consumer. An organism
that feeds on a first-order consumer is called a
second-order consumer, and so on. The level
occupied by a consumer in a food chain is
referred to as a feeding or TROPHIC level. First-
order consumers occupy the first trophic level;
second-order consumers occupy the second
trophic level, and so on.

58. Food webs The interrelationship between many food chains is called a

59. Biomass Biomass is an estimate of the amount of matter
in a given population of organisms. Biomass
for different trophic levels is compared in a
biomass pyramid. A biomass pyramid shows
how the quantity of matter in living things
changes along a food chain.

60. Biomass pyramid The base of the pyramid represents the matter in
producers. The next level shows biomass of 1st order consumers and so on.

61. Biomass pyramid At each level in the pyramid biomass is smaller
than in the trophic level below. At each level
biomass is lost.
An energy pyramid shows the total energy in
trophic levels and how that energy is lost
along a food chain.

62. Energy pyramid

63. Decomposers Organisms that use the organic matter of
dead plants and animals are called
decomposers. They release digestive enzymes
to break down organic matter and then absorb
the products of digestion. Decomposers include
fungi and bacteria. Decomposers do not fit
readily into one trophic level.

64. Adaptations All organisms have adaptations that help them to
survive. Organisms that are adapted to their
environment are able to:
obtain air, water, food and nutrients
cope with physical conditions such as temperature, light and heat
defend themselves from their natural enemies
reproduce
respond to changes around them

65. Adaptations
Structural adaptations are the physical characteristics of an organism (e.g., skin color, shape, body covering).
Behavioral adaptations are the ways in which an organism behaves.
Physiological adaptations are those that allow an organism to perform certain biochemical reactions (e.g., making venom, secreting slime, being able to keep a constant body temperature).