Inquiry Question: What effect can one species have on the other
species in a community?
Organisation within ecosystems
Biosphere contains all the living thighs on Earth
Environments can positively or negatively impact an organism - An
organism living and non-living surrounds its ecosystem
Impact of Abiotic Factors
Abiotic factors are not easily disturbed
Own unique way of thriving within the limits of the abiotic
environment
Water is a very effective filter of sunlight
Rapid drop in temperature
Oxygen levels
Impact Of Biotic Factors
Living organisms can affect each other by predation and
symbiosis but also have an equally profound effect on resources
Food sources, mates, light, nutrients, water
Predation
Predator obtains its food by killing and eating another animals
Found in aquatic or terrestrial ecosystems
Spider capturing bugs in its web and eating it
Competition
Competition is usually for a resource in the environment that is
limited supply but valuable for survival
All competition involves risk to the competitors and the rewards
must outweigh the inherent risk
Intraspecific → Within a species
Interspecific → Between species
Symbiotic
Interactions in which two organisms live together in a close
relationship that is beneficial to at least one of them
Obligate relationship → species depend on each other to live
Mutualism
Both organism benefit
Clownfish and sea anemone → Clown fish is protected by the sea
anemone whilst the fish cleans the plant
Commensalism
One species is benefited whilst the other is not harmed or helped
Birds that live in hollow holes in trees
Parasitism
One species benefits whilst the other is harmed
Parasite obtains shelter from the host organism while feeding upon
the tissue and fluids
Ecological Niches occupied by Species
The part of an ecosystem that the organism occupies is called a
niche
Refers to all the resources that a species uses, including biotic and
abiotic
The process of having unique living strategies
Fundamental niche → The perfect conditions and resources for an
organism to live and reproduce
Realised Niche → All the aspects of the ecosystem including the
interactions of other species
Consequences in ecosystems
Predation
Effect the distribution and abundance of prey
If the prey can reproduce fast enough, rates wont drop
- Prey and predators are in direct
proportion
Competition
Effects reproduction and survival rates
More food sources → More abundance of both species
Different traits will boost a species survival of getting resources
Symbiosis
Increased evolutionary diversification
Development of new species from the integration of genetic material
More resilient ecosystems → Biodiversity
Disease
Any process that adversely affects the normal functioning of tissue
in a living organism
Bacteria, virus, Pathogen
Alter the balance of food webs → Affected species will decline in
numbers
Recent Extinction
Climate Change
Continent dried out
Rainforests were contracting – stored moisture and returned
moisture to the atmosphere.
Eucalypt forests replaced these, and water was not as efficiently
retained.
Became hotter and drier, fires broke out due to lightning.
Plants and animals that survived the drought and fire reproduced,
changing the flora and fauna.
Arrival Of Humans
Aboriginal people arrived successful predators.
Used ‘fire stick’ farming techniques.
Introduction of dingoes may have reduced the diversity of carnivore
predators.
Level Of Nutrients
Low level of nutrients in the soil → dry
Led to smaller animals →F can be sustained on less
Evidence for this can be seen in the smaller size of mammals in
Australia compared to counterparts across the world.
Past Ecosystems
Inquiry Question: How do selection pressures within an ecosystem
influence evolutionary change?
Past Ecosystems
It is unclear when humans first became interested in fossils.
Philosophers hinted that fossils were evidence of previous life.
Law of superposition → oldest layer at bottom and newest at top.
Aboriginal Rock Paintings
Longest unbroken tradition in the world
Humans are driven by nature to record details of their existence
West Kimberly’s rock paintings
Radiometric dating is used to date the paintings
Uranium/Thorium can be used to underlying calcite formations to show
when they were formed
Types and abundance of animals depicted in paintings changed overtime
Geological Evidence
Allows reconstruction of timeline of events
Represents the course of changes in geological and fossil deposits
Banded iron Formations
Form of geochemical evidence found in Australia
Earth's atmosphere has undergone changes, change from anaerobic to
aerobic
Form of iron rich and iron poor sediments
Prokaryotes lead to an increase in oxygen concentration in the
ocean, leading to precipitation of insoluble iron oxide
Precipitate accumulated at the bottom of the ocean, forming an iron
rich layer of sediments
Great oxygenation event transformed Earth’s atmosphere
Resulted in much larger and multicellular organism→ Organisms had to
adapt to more oxygen
Palaeontological Evidence
Fossils offer clues to the selection pressures of living things like
the climate and environment at the time
Found in sedimentary rocks → Preserve evidence rather than
destroying it
Fossilised soils contain large concentrations of carbon that
indicate presence of life
Chemosynthesis is a process where organisms use inorganic compounds
available from their environment.
The fossils formed from stromalites provide valuable informationof
early orgaims and the environment in which they lived
Ice Core Drilling
Accumulation of ice layers in places such as antarctica leaves
an annual record of gas and dust in that atmosphere of that time
Scientists can drill into the ice, extract gases and reconstruct the
climate record
Increases understanding of past environments
Radiometric Dating
Process where scientists determine the age in years of a fossil,
rock or mineral
Based off the content of radioactive isotopes
Unstable isotopes change to form stable isotopes → Undergoes
radioactive decay which scientists can compare to examine the life of
the rock
More half lives → Older
Rate of decay is calculated using the age equation that
compares the abundance of the naturally occurring isotope with the
abundance of the decay product.
Gas Analysis
Scientists can use data in ice cores to reconstruct atmospheric
concentrations of certain gases, particularly CO~2~ and O~~
2.
CO~2~ is a normal part of Earth’s atmosphere along with nitrogen,
oxygen, argon and other trace gases
But CO~2~ is also considered a ‘greenhouse gas’ that traps solar
radiation keeping the Earth warm enough to sustain life
However, increasing CO~2~ in atmosphere is likely to increase
Earth’s atmospheric temperature, known as the ’enhanced greenhouse
effect’ or ‘global warming’
Scientists use ancient CO~2~ levels~~ to infer past climates -
warming or cooling would have a direct effect on the types of plants
and animals that are suited to survive in such a climate
Oxygen has three naturally occurring isotopes: ^16^ ^^O, ^17^
^^O and ^18^ ^^O which are incorporated into water molecules. The
ratio of ^18^ O/^^^16^ ^^O in analysed ice core samples indicates
ancient water temperatures which scientists can use to reconstruct
water temperatures on Earth.
Small Mammals
We Can use fossil of past animals to show similarities and
differences to present day animals and therefore propose
evolutionary relationships between them.
When comparing the modern platypus to fossils, body shape became
smaller + more simplified.
We can infer a change in diet as dentition is different
Habitat reduced in size → May have become vulnerable.
Reasons for Change
Australia’s change in climate due to the split of Gondwana
Climate change
Arrival of indigenous
Introduction of non native plant + animals → invasive species →
Destroys or affects the natural food web
Future Ecosystems
Inquiry Question: How can human activity impact an ecosystem?
Human Induced Species
Increasing Population
Selective breeding, use of fertilisers, pesticides and herbicides
Medical breakthroughs with antibiotics, better hygiene and
vaccinations
Increasing populations of humans lead to an increase of the demand
of resources from ecosystems
Selective breeding limits the biodiversity of species, hence making
them more susceptible to being majorly effected by disease or change
Agriculture
Removal of trees leaves the soil vulnerable to erosion → Loss of
valuable minerals for an ecosystem
Pollutions harms the water and atmosphere
Irrigation was developed alongside the domestication of plants
Selective breeding of crops and livestock radically altered their
features to favour large yields
Introduced Species
Many invasive species out compete native species for light, water,
habitats and nutrients
Change the environments to alter the microclimate of the areas to
favour their own development
Completely alter the food web system which has detrimental effects
on the rest of the ecosystem
Land Clearing
Refers to the removal of native vegetation for urban and
agricultural development
Removes nesting and habitats of native animals → Cannot reestablish
anywhere else.
Extinction
Habitat loss is the leading cause of extinction
Most historic extinctions have occurred on islands because a small
habitat loss has devastating effects
Extinction opened niches for surviving organism to expand into →
Rapid development of species
Past To Inform the Future
Can estimate rates of extinction by studying recorded extinction
events, examining fossil record and by analysing modern trends
in habitat loss
Over exploitation of resources → Harvesting an amount that is not
sustainable over time
Introduced species → New species effect relationships due to
competition, predation and disease
Disruption of ecological relationships → loss of available niches
alter the distribution and abundance of species
Biodiversity
Genetic diversity → Intraspecies diversity in traits that makes
a population resilient to environmental changes
Species Diversity → Variety of species in an ecosystem
Ecosystem diversity → Variety of ecosystems available in a broader
area such a continents or globally
Climate Change
Greenhouse Effect
Solar radiation reaches and penetrates earths atmosphere
Some energy is trapped and absorbed into the land and ocean
Keeps earth warm and sustainable
Enhanced Greenhouse
Increase of concentration of greenhouse gases
More energy being absorbed in oceans and land
Warmer climate
External factors → Solar input from the sun, Earths variety in orbit
Internal factors → Active release of CO2 from volcanoes, diffusion
of CO2 from ocean, less reflection of light from ice (Melting ice is
bad)
Human Factors → burning fossil fuels, agriculture, land clearing
Models Predicting Biodiversity
Resources increase slow
Humans grow quick
Humans will outgrow their ability to feed themselves
Greater fertility will lead to starvation
Keep numbers and population in check
Mining Sites
Required to follow laws and strict guidelines, which include
submitting information on how they intended to ensure minimal
harm to environment
All mining companies must complete an environmental impact statement
as a part of their license application
Land Degradation and Agriculture
Marked improvement in the management of Australiansoils and
waterways
Farm owners can have their land inspected by scientists
Management of salinity and erosion are high priorities
Biological controls are being used to maintain pests
