1. 7: Environmental Factors & Their Influence

2. The Environment:
is our surroundings or external factors and forces (conditions) that affect an organism or a group of organisms
- Physical (air, water, soil)
Biological (biosphere: plants; animals)
- Societal (our culture; political system)

3. Earth’s Spheres ATMOSPHERE Air BIOSPHERE Living Things
Contains all the air in Earth’s system.
BIOSPHERE Living Things
Contains all of Earth’s living things— microorganisms, plants, and animals.
LITHOSPHERE Land
Contains all the cold, hard, solid land of Earth’s crust (surface), the semi-solid land underneath the crust, and the liquid land near the center.
HYDROSPHERE Water
Contains all the solid, liquid, and gaseous water of Earth.

5. EVENT Atmosphere Biosphere Lithosphere Hydrosphere Mt. Pinatubo
Eruption
Atmosphere
Biosphere
Lithosphere
Hydrosphere

6. Ecology
The study of interactions that take place between organisms and their environment.
It explains how living organisms affect each other and the world they live in.

8. Abiotic/Biotic factors
In an ecosystem, there are various factors that affect the survival and welfare of a population.
These factors are classified as:
abiotic
biotic.

9. Abiotic/Biotic factors
In an ecosystem, there are various factors that affect the survival and welfare of a population.
These factors are classified as:
abiotic
biotic.

10. Abiotic factors : involve all those factors that are non-living.
For example-
Soil pH
Soil Humidity
Soil Temperature
Air Temperature
Wind Speed
Sunlight Intensity
Soil Nutrients

11. Biotic factors : involve all those factors that are living.
For example-
Competitors
Predators
Decomposers
Population Density
Disease

12. Limiting Factors
Some abiotic and biotic factors affect the organisms sufficiently to limit population growth.
These are known as limiting factors.
The factor may be too little in quantity or too much.
For example, the limiting factor for a plant population near a chemical factory may be the soil pH.

13. Liebigs Law of the Minimum
The success of an organism depends on several requirements, if one of these is present in minimal quantities this will limit the organism regardless of the abundance of the others.

15. Limiting Factor = Nitrogen
No matter how much of the other minerals you have once you run out of nitrogen plants can not grow.
So nitrogen in this example is the limiting factor.

16. Some further examples of limiting factors:
Oxygen in a billabong
Water in a desert
Light in the ocean depths
Nutrients in the upper layers of the sea

17. Shelford’s Law of Tolerance
Organisms have an ecological maximum and minimum, with a range in between which represents the “limits of tolerance”.
Too Much or Too Little!

18. Range of Tolerance
Every population thrives in an optimal range of abiotic factors.
Beyond this range, one finds less and less numbers of these organisms.
In an ecosystem, it is harder to represent what this optimal range is, since a host of factors affect the survivability of this population.
Often, the range is shown for each factor, and this is known as the range of tolerance.

19. Too dry
Too wet
Just right

20. Just Right
Too Cold!
Too Hot!

21. Tolerance Limits

23. Tolerance to heavy metals

25. Variation in ranges of tolerance

26. Habitat
A habitat : is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. eg
an ocean,
a lake,
a tree,
a rotting log,
the alimentary tract etc

27. Ecological Niche
The Ecological Niche of an organism describes how that particular individual "fits" into its ecosystem.
Within its habitat, it must make use of available resources, withstand abiotic and biotic factors, with the help of adaptations
the role that the individual organism plays in its nonliving and living environment.
Habitat and Niche

28. An investigation into the niche of two species of barnacles

29. Describe what happened to the distribution/realised niche of Cthamalus once Balanus was removed.
Why might this change have occurred?

30. The wider the species range of tolerance the greater the potential geographic range or distribution

31. Specialist species
Species that have relatively tightly defined niches and have a narrow range of tolerance.
Such species are better off when their preferred environment remains stable.
Pandas are considered to be a specialist species.

32. Generalist species
Species that have broad niches and tolerate larger changes in the environment.
Such species can survive in a variety of different conditions.
Humans are considered to be a generalist species.

33. The description of a niche may include descriptions of the organism's life history, habitat, and place in the food chain.
A ringtailed possum is a nocturnal marsupial herbivore that inhabits a range of forests , woodlands, shrublands and is adapted to urban gardens.

34. Feeding Niches for Wading Birds

35. Environment:
The external surroundings including all of the biotic and abiotic factors that surround and affect the survival and development of an organism or population.
Eg Rocks, minerals, soil, water, air, mountains, rivers , oceans, plants , animals etc

36. Populations: the number of a specific species of organisms living in a specific habitat at a specific time.
eg: population of dolphins in Port Phillip bay

37. Community: A group of interdependent organisms living and interacting with each other in the same habitat.
eg the Port Phillip Bay Community includes populations of algae. microorganisms, invertebrates, fish , birds, mammals including humans
Dolphins hunting fish using sea snakes!!!!!!

38. An ecosystem:
is a natural system consisting of all plants, animals and microorganisms (biotic factors) in an area functioning together with all the non-living physical (abiotic factors) of the environment .
Ecosystem = habitat + community Eg
a billabong ecosystem
a river ecosystem
a desert ecosystem,
Port Phillip Bay etc

39. In order to systematically study and understand ecosystems- we make both:
Qualitative observations
(eg the water temperature is mild )
Quantitative observations
(eg the water temperature range is 120C – 220C with an average temperature of 16 0C etc….)

40. Within habitats there are:
Systematic quantitative measurements or monitoring enable us to determine…
Within habitats there are:
microhabitats = small scale differences in abiotic factors
These variations affect the biotic factors such as type and distribution of species

46. Some methods of monitoring and categorisation of abiotic and biotic factors are very specific or narrow
These can give us important information about potential effects on the environment and ecosystems
eg rainfall is a narrow measure however it is a critically important factor which determines what flora and fauna may inhabit an environment

47. Climatic factors: individually and together are important descriptors of environment and determinants of the presence and pattern of life in an environment.

48. Climate encompasses the statistics of:
temperature,
humidity,
atmospheric pressure,
wind,
rainfall,
atmospheric particle count and
numerous other meteorological elements in a given region over long periods of time.

49. Mapping individual abiotic climatic factors can reflect biotic patterns

51. Combining several climatic factors we can classify the Australian environment in to the following major classification zones

53. Geomophological factors such as:
altitude
topology - lay of the land (flatness/steepness)
geology rocks- minerals soils
etc
Are all abiotic factors that are important determinants of biotic distribution.

54. Australian Elevation Map

55. Soil Distribution in Australia

56. Botanists seeking to understand our vegetation look for patterns in the distribution of identifiable vegetation communities.
The type of plants and their distribution reflect the underlying geomorphology and climate of the area and in turn affect the distribution of animals and other life.

57. Specht’s Classification of Australian Vegetation
Specht developed a system which has become widely used both in Australia and overseas.
It is based on three elements:
Identification of the lifeform of the tallest stratum (or layer) of plants in an area (e.g., trees, shrubs, hummock grasses or other herbs).
Determination of the height and/or type of vegetation in the tallest stratum (e.g., ‘trees over 30m’, or ‘shrubs, non-sclerophyllous’, etc.).
Determination of the projective foliage cover of the tallest stratum.
This is the percentage of area which is covered by that foliage (leaves).

59. Foliage cover
Open 30-70%
Closed > 70%
< 10%
Open %

61. Tall closed forest
Tall Closed Forest
Tall Open Forest
Tall Woodland

62. Low closed forest & Tall closed shrublands

63. Grasslands

64. Low closed herbfield