BIOLOGY
Topic 1 (8.2): A Local Ecosystem
Abiotic Factors
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Viscosity: Degree of difficulty experienced by an organism to pass through a medium.
Buoyancy: Support offered by a substance, such as a liquid or gas, to an organism.
Variation in temperature: Temperature can vary enormously in terrestrial
environments. It is more stable in aquatic environments.
Availability of gases, water and ions: Both oxygen and carbon dioxide are found in the
atmosphere and in water. Less availability of gases and water higher in the atmosphere
so organisms stay low for gases, water and ions as ions are dissolved in the water.
Light Penetration: Without light, plants cannot photosynthesise. Less light lower in the
water.
Pressure Variation: In aquatic environments, the density of water causes pressure to
increase rapidly with increasing depth. In the terrestrial environment, pressure will
decrease with altitude, which can significantly affect gas exchange
Physical Forces: Wind, rain, tides and currents can also affect organisms and determine
their location
Biotic Factors
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Competition for Resources: Organisms consuming the same food, space, e.c.t. will have
to fight for the resources.
Food Supply: For second order consumers, the amount of food available for
consumption greatly impacts the abundance of a population.
Predation: For any organism that has a consumer higher up in the food chain, their
population will rely on the amount of predation.
Disease Agents: A population of any organism can significantly decrease due to a
disease.
Rate of Reproduction: As rate of reproduction increase, so does the abundance of a
population.
Distribution and Abundance
Distribution is the area a species inhabits (where you find it).
Abundance is the number of organism you fins in a measured area.
Sampling Techniques
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Transect: Cross section of an area, used to record type and number of species present.
Useful for recording the relationship between a species and the abiotic factors in
the area.
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Quadrats: Square, rectangular or circular frame of chosen size. Marks out an area
in which the vegetation is to be sampled. Shape and size of quadrat depends on
type of vegetation. May be located randomly over the area being sampled or at
regular intervals along a transect or grid.
Capture Recapture: More difficult to estimate the population of animals than
plants due to movement of animals, being nocturnal, hiding and being scared off
by the researcher. It involves tagging or marking a sample of the population then
releasing it. Total population = (number of animals tagged times number of
recaptured) over (Average number of animals tagged and recaptured)
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Energy in Ecosystem
Photosynthesis: Carbon Dioxide + Water  Oxygen + Glucose + Water (can be separated into
the light dependent and independent stages).
Respiration: Glucose + Oxygen  Carbon Dioxide + Water + Energy
Uses of Energy: Growth, repair, reproduction, movement, maintaining body temperature.
Autotrophs: Make their own food.
Heterotrophs: Gather food from other sources.
Biotic Relationships
Name
Predation
Parasitism
Commensalism
Mutualism
Allelopathy
Description
Capture and killing of
other animals for food
Parasites feed of it’s
hosts tissues or food
in the hosts gut
Only one species will
benefit but the other
will not be harmed
Two species derive
some benefit from
living together
A process where
allelochemicals are
released to influence
the growth of
neighbours. An
example of
competition
Example
Fox on rabbits
Tick on Dogs
Organisms (+,-, 0)
Organism 1: +
Organism 2: Organism 1: +
Organism 2: -
Clownfish living in
anemones and/or
oyster living on
pneumatophores of
mangrove
Algae and fungi
(lichen)
Organism 1: +
Organism 2: 0
Casuarina on other
plants
Organism 1: +
Organism 2: -
Organism 1: +
Organism 2: +
Transfer of Food and Mass
Food Chain: A representation of a section of an ecosystem. E.g. Producer  First order consumer 
Second order consumer  Decomposer (Each spot represents a trophic level)
Food Webs: A network of interconnecting food chains representing a whole ecosystem.
Biomass Pyramid: shows how much material (about 10%) is passed on to successive trophic
levels. Shows the mass of all living organisms at each trophic level at a particular time.
Energy Pyramid: measures the flow of energy (about 10%) of all living organisms through
trophic levels during a fixed time period. Shows where the available energy lies in an
ecosystem and what is lost from each level as heat.
Adaptions
Structural: Shape and size e.g. fur, large SA to volume ratio
Physiological: How it functions e.g. high metabolic rate
Behavioural: How it acts e.g. licking fur, nocturnal activity
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Topic 2 (8.3): Patterns in Nature
Cell Theory
1. All living things are composed of cells and cells products
2. New cells are formed only by the division of pre-existing cells
3. The cells contains inherited information (genes) that are used as instructions for growth,
functioning, and development
4. The cell is the function unit of life; the chemical reactions of take place within cells
Robert Hooke (1663): First person to observe a cell. Looked at cork through a microscope.
Robert Brown (1801): Discovered the cell nucleus.
Rudolph Virchow (1874): Found through observing cells through a microscope that all cells come
from pre-existing cells.
Technological Advancement
Key: A – Animal, P – Plant, E – Electron Microscope, M – Microscope.
Organelle
Structure
Endoplasmic Reticulum (A+P+E)
Network of flat folded
membranes; large surface
area.
Ribosomes (A+P+E)
Small and rounded often
attached to ER.
Lysosomes (A+P+E)
Fluid filled sacs surrounded
by a single membrane.
Centrosome (A+P+E)
Oval shaped, A double
membrane with inner layer
folded.
Cytoskeleton (A+P+E)
In cytoplasm
Cell Wall (P+E+M)
Built up of strands of
cellulose fibres.
Cell Membrane (A+P+E+M)
Semi-permeable/ selectively
permeable. Consisting of
proteins and lipids
Nucleus (A+P+E+M)
Membrane bound sphere
containing chromosomes.
Nucleolus (A+P+E)
Spherical region within the
nuclear membrane.
Vacuole (A+P+E+M)
Cytoplasm (A+P+E+M)
Chloroplasts (P+E+M)
Golgi Body (A+P+E)
Large fluid filled sacs.
Surrounded by one
membrane.
90% water, contains
dissolved chemical
substances.
Ovular in shape, Green.
Surrounded by double
membrane.
Made of flat membranes
Function
Involved in the transport of
materials.
Protein synthesis.
Breaks down worn out cell
organelles for recycling.
Site of aerobic respiration –
produces ATP a form of
chemical energy.
Holds organelles in place
Strength and support.
Separates cell contents from
its surrounding. Controls
what enters and exits the cell
Controls cell activities;
contains DNA
Makes ribosomes
Manufacture of proteins;
active part of DNA
Stores food, water and
waste.
Growth and respiration.
Site of Photosynthesis.
Processing, packaging and
sorting of cell products
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Organic compounds
Organic Compounds
Carbohydrates:
Glucose
Fructose
Starch
Cellulose
Lipids:
Fats, oils, waxes, steroids
Lignin
Protein
Nucleic Acid (DNA, RNA)
Elements
Carbon
Hydrogen
Oxygen
Carbon
Hydrogen
Oxygen
Carbon
Hydrogen
Oxygen
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus
Sulfur
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus
Chemical Test
Testape (glucose):
Yellow green
Iodine (starch):
Yellow purple/black
Benedict’s Solution (glucose):
Blue --heat-> orange/red
Filter paper (brown paper):
stained translucent
Toluidine
Biuret Test:
Turns purple, violet or red.
Diffusion and Osmosis
Diffusion: the process by which substances move from an area of high concentration to an area of
low concentration.
Osmosis: a special case of diffusion, it is the movement of water particles through a semi-permeable
membrane from an area of high concentration of water to an area of low concentration of water.
Membrane
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Surface Area to Volume
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The amount of material that can be moved into and out of a cell depends on the
surface area of the cell membrane available.
The size (volume) of a cell determines how much material that needs to be moved
into and out of the cell.
As Cell sizes increases, the surface area to volume ratio decreases
The larger the SA:V ratio, the more efficient the movement of substances into and out of
the cell. Therefore, smaller objects will be very efficient have a have a higher rate of
movement of substances.
Cells cannot grow too big because a cell needs substances to move in and out at a rate that
will allow enough materials to move in and out for the cell to live.
Order of Size
Atoms  Molecules  Organelles  Cells  Tissues  Organs  Systems  Organism
Structure of Plants
Leaf
Description
Structure
Cuticle
A waxy layer covering the leaf
surface
Function
This waterproof layer reduces the evaporation of
water from the leaf. Its shiny surface also reflects
light, which helps reduce evaporation.
Epidermis
A layer of cells on the upper
This is an outer layer of non-photosynthetic cells
and lower surfaces of the leaf
on the upper and lower sides of the leaf.
Palisade
Densely packed photosynthetic This is the main site of photosynthesis. These
mesophyll
cells
cells are packed with chloroplasts.
Spongy
Loosely packed photosynthetic This is the main area for gas exchange in the leaf
mesophyll
cells
and the site of photosynthesis
Stomata
Openings in the epidermis
Gases enter and leave the leaf here.
Guard cells
Cells of the stomata
These cells control the opening and closing of the
stomata and contain chloroplasts.
Vascular
Xylem and phloem tissue
Xylem carries water from the roots to leaves.
bundles
Phloem carries sucrose from leaves to other parts
of the plant.
Chloroplasts Found in mesophyll
These organelles perform photosynthesis.
Structure
Root hair cell
Description
Long extension of root cell to
increase SA
Function
Provides large SA for absorption of
water and minerals
Xylem
Long tube, strengthen with
lignin, allows water to pass
through
Connected cells with sieves
plates at the end.
Transports water from roots to leaves,
doesn’t require energy. Only moves
one way
Minerals and food is transported
around the plant, from the leaves.
Stomata
Found in epidermis. Each pore
has guard cell on either side,
Allow gaseous exchange to occur. Can
close to reduce water loss by plant.
Lenticels
Breaks in bark
Allows gas exchange in stem for living
cells behind tough bark
Phloem
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Digestive Systems
Herbivore
Carnivore
Example of animal
Chemical composition of diet
Sheep, cow, kangaroo
Cellulose and starch, some
sugar, protein and oils
Structures involved in
digesting certain foods
Large flat teeth, jaws that can
move side to side. Microbes
and enzymes in digestive tract.
Teeth and jaw: to physically
break down matter
Microbes: Digest fibre, break
down cellulose
Long, complex
Dog, tiger, lion
High amounts of protein, little
fibre and fat, little
carbohydrates
Large canines, short and
powerful jaw for vertical
movement only.
Teeth: Slice, cut flesh because
protein is easy to break down
(increase surface area)– no
cellulose
Short, simple
Functions of structures
Relative length and complexity
Gaseous Exchange Surfaces
Feature
Insect
Pathway of
Spiracle > trachea >
oxygen into
tracheole >
body
interstitial fluid >
cell
Pathway of
Interstitial fluid >
carbon dioxide
tracheole > trachea
out of body
> spiracle
Fish
Mouth >
gill >blood
> cell
Frog
Mouth > Buccal
cavity > lungs >
blood > cell
Mammal
Mouth/nose >
windpipe > lungs >
alveoli > blood > cell
Blood > gill
> water
Blood > skin
Blood > lungs (alveoli)
> mouth
Meiosis and Mitosis
Where Mitosis Takes Place:
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Plants: mitosis occurs in root tips and stems
Insects: mitosis occurs during metamorphosis, everywhere
Mammals: mitosis occurs in most body cells (except nerve cells and red blood cells).
Especially in the stomach lining and skin
Cytokinesis: The splitting of the cytoplasm during mitosis.
Important  People  Make  A lot of  Telephone  Calls
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Topic 3 (8.4): Life on Earth
Scientific Theories of the Evolution of Organic Chemicals
Panspermia: Organic molecules came from asteroids from outer space. Evidence has been found in
meteorites of fossilised organic molecules.
Chemical Evolution: Haldane and Oparin suggested that the conditions of early earth (volcanic
activity, electric storms, atmosphere of H2, CO, CO2, CH4 (methane), N2, NH3 (ammonia).
Urey and Miller Experiment
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Urey and Miller designed an experiment in 1953 to prove the theory of Oparin and Haldane,
stating that the conditions of early Earth allowed for organic chemicals to form.
The experiment consisted of a chamber containing methane, ammonia, hydrogen and water
(to recreate Earths early atmosphere) which was continuously exposed to electric discharge
from tungsten electrodes (lightning) for a week.
The experiment resulted in organic molecules forming, proving Oparin and Haldane’s theory.
This experiment is significant because it provides clear evidence supporting the theory of life
on earth.
Technological Advancement
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Genetic Sequencing: Allows us to compare organisms and find where they have evolved
from and allows assists classification of organisms.
Carbon dating: helps us to understand the ages of organisms and also the evolution of
organisms.
Order of Evolution
1. Organic molecules (4 billion years ago)
2. Membranes (3.5 – 4 billion years ago)
3. Prokaryotic heterotrophic cells – do not contain membrane bound organelles (2.5 – 3.5
billion years ago)
4. Prokaryotic autotrophic cells e.g. cyanobacteria which are still around today – do not contain
membrane bound organelles (2 -2.5 billion years ago)
5. Eukaryotic cells – contain membrane bound organelles (1.2 – 1.4 billion years ago)
6. Colonial organisms (0.6 – 1.2 billion years ago)
7. Multicellular organisms (600 million years ago)
Evidence for When Life Originated
Paleontological: The discovery of fossils. Through the use of carbon dating it has been found that
simpler organisms existed earlier.
Geographical: Stromatolites (rock formations created by cyanobacteria), banded iron formations
(suggesting the existence of oxygen).
Significance of Oxygen
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The change from an anoxic atmosphere to an oxic atmosphere allowed organism that
performed respiration to evolve.
It also lead to the formation of the ozone layer which allowed for more sensitive organisms
to develop.
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Classification
Classification: the placing of organisms into hierarchal on levels on differences. Such a system places
organisms in groups to show degrees of similarities and diversity.
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The large number and diversity of life forms make it essential that scientists classify
organisms
It enables organisms to be identified quickly and accurately
It makes communication simpler between biologists
It lets newly discovered organisms to belong to particular groups
It enables similarities/differences in groups to be observed
Two Kingdom Classification: Plantae/Animalia
Three Kingdom Classification: Monera/Plantae/Animalia
Four Kingdom Classification: Monera/Plants/Animals/Fungi
Five Kingdom Classification: Monera/Plants/Animals/Fungi/Protista
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Monera: Prokaryotic
Protista: Eukaryotic, unicellular
Fungi: Eukaryotic, multicellular, heterotrophic, no locomotion, cell wall
Plants: Eukaryotic, multicellular, autotrophic, no locomotion, cell wall
Animals: Eukaryotic, multicellular, heterotrophic, locomotion
Hierarchy of Classifications: Kingdom  Phylum  Class  Order  Family  Genes  Species.
King Philip came over from German soil
Binomial Naming System
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The first word with a capital letter represents the GENUS of the organism.
The second word, represents the SPECIES of the organism and as no capital letters.
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Topic 4 (8.5): Evolution of Australian Biota *not section 4
Evidence Supporting the Theory of Gondwana
Matching Continental Margins: The second word, represents the SPECIES of the organism and as no
capital letters.
Positions of Mid-Ocean Ridges: The position of mid-oceanic ridges lines up accurately with how the
continents would have separated. These ridges are caused by spreading in the oceanic crust and
therefore force the continents apart.
Spreading zones between continental plates: Spreading zones (often caused by mid-ocean ridges)
are located between continents suggesting that they separated from one big continent.
Fossils in common on Gondwanan continents: Fossils of almost the same species have been located
on separate continents and the most feasible reason for this is that the continents were once
connected.
Similarities between present-day organisms on Gondwanan continents: Marsupials and ratites are
only found in Australia, New Guinea and South America which are three continents that where
joined in the Gondwanaland theory which further reinforces it.
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Variations
Variation: the differences in characteristics of individuals within a population - it occurs due to
genetic mutations or environmental adaptations or combination of both.
Environment: many birds of the same species show variation between different geographical areas
such as size, beak length and colour.
Hereditary: in humans – eye colour, skin colour, height, build, etc are all variations that make each
individual different from another.
Darwin/Wallace Theory: in 1858 both Charles Darwin and Alfred Wallace proposed the idea of
natural selection. The theory states that as a population that reproduces sexually varies the
environmental selective pressures causes only the individuals best suited to that environment to
survive and those individuals will then pass on the trait to their offspring causing a variation in the
population. Darwin also found when travelling to Australia that there were similar species to in
Europe suggesting that species subject to similar environments could evolve similar features.
Evidence Showing Australia’s Changing Environment
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Evidence of Glaciers: Polished rocks where rivers would have been suggest that an icy river
once flowed over them.
Evidence of Swamps: Fossils of plants that are known to live in swamp environments are
found in non-swamp environments.
Evidence of Rainforest in Central Australia: Discovery of plants that are known to live in
rainforests.
Possible reasons for these changes include: climate change and the impact of humans.
Meiosis and Mitosis
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External and Internal Fertilisation
Aquatic
Internal
Not a necessary adaptation however
it is successful.
Fewer gametes are required due to
the higher chance of fertilisation
Terrestrial Only type of fertilisation possible on
land because of the need of water
Eternal
Usually highly successful
Gametes do not dry out or dehydrate
However, large numbers of gametes must
be produced to compensate for losses from
predation, disease and dispersal to
unsuitable environments
Are not successful due to their complete
reliance upon a water environment for
fertilisation and the transfer of gametes
It is very successful as direct transfer
avoids dehydration and loss by
dispersal of gametes.
Fewer female gametes are required
Due to the enclosed space, the
offspring is protected from predators
and disease
Pollination
Asexual and Sexual Reproduction
Sexual Reproduction: The coming together of two gametes from separate parents resulting in the
variation of a species. This is advantages when the environment is changing.
Asexual Reproduction: The reproduction of an organism through mitosis in which a exact copy is
made. This is advantages when the environment stays constant.
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