Prelim revision!

MODULE 1

[Cell structure3
Inquiry question: what distinguishes one cell fromanother?
Cells can be broadly classified into 2 main types: prokaryotic &
eukaryotic.
1 .
Investigating a variety of cells:
Protraryotic cells: cells that lack a membrane-bound
nucleus (e.g., bacteria and archea). Their DNA is free-
floating in the cytoplasm, and they have a simpler
structure with fewer organelles. They lack mitochondria
or chloroplasts and reproduce primarily through binary
fission.
Eukaryotic cells: cells with a nucleus enclosed by a
membrane and various organelles (e.g., plant, animal,
fungi, and protist cells).
2 .
Technologies for studying cell structure:
Light microscopes: offers a basic view of cell shape,
structure, and organelles, suitable for examining living
cells in action.
Electron microscopes: provide high-resolution images of
internal structures, making it ideal for study organelles in
detail.
Fluorescent microscopy: uses fluorescent dyes to tag and
visualise specific cellular components s aiding in
understanding the distribution & behaviour of these
structures.
.
3 Comparing and contrasting organelles:
Nucleus (eukaryotic only): contains DNA and controls cell
activities.
Ribosomes (in both types): responsible for protein
synthesis.
Cell membrane: found in all cells; regulates the
movement of substances.
 Mitochondria (eukaryotic): the powerhouse of the cell,
generates ATP.
Chloroplasts (in plants and algae): sites of photosynthesis.

[ Cell function 3
Inquiry question: how do cells coordinate activities within
their internal and external environments?
Cells need to constantly interact with their environment to
regulate internet conditions & respond to external stimuli.
This involves processes that control the exchange of
materials, energy requirements, and biochemical reactions.
7 .
Movement of materials into and out of cells:
Diffusion: the passive movement of molecules from
areas of higher concentration to lower concentration.
It's the main method by which gases (e.g., oxygen,
carbon dioxide) move across cell membranes.
Osmosis: A specific type of diffusion where water
moves through a selectively permeable membrane,
balancing the concentration of solutes.
Active transport: movement of molecules against a
concentration gradient (from low to high concentration)
using energy in the form of ATP. This is essential for
absorbing ions little sodium and potassium.
Endocytosis: the process by which cells engulf large
molecules or particles by folding the cell membrane
inward, forming a vesicle.
Exocytosis: cells use this process to export large molecules
like proteins by fusing vesicles with the plasma membrane.
L
Surface-area-to-volume ratio: cells must optimise this
ratio to efficiently exchange materials. Larger surface
areas relative to volume enable faster exchange, which is
why cells are often small or contain foods (e.g, villi in the
intestines)
 Concentration Gradients: The rate at which materials
move into or out of a cell depends on the difference in
concentration inside and outside the cell.
2 .
Cell requirements:
4
Energy:
4
Light energy: used by photosynthetic orgnisms (plants,
algae) to convert sunlight into chemical during
photosynthesis.
Chemical energy: All cells, including animals and plants,
use energy stored in molecules like glucose, which is
broken down through cellular respiration to produce
ATP (adenosine triphosphate).
Matter:
Gases: oxygen is needed for aerobic respiration, while
carbon dioxide is released as a waste product. In plants,
carbon dioxide is used in photosynthesis.
Nutrients and Ions: Cells require simple nutrients (e.g.,
glucose, amino acids) and ions (e.g., potassium, calcium)
for their metabolism and structural integrity.
Waste removal: Byproducts of cellular metabolism (e.g.,
carbon dioxide, ammonia) must be removed to prevent
toxicity.
3 .
Biochemical processes:
Photosynthesis: In chloroplasts: light energy is converted
into chemical energy stored in glucose. This process is
essential for plants and other photosynthetic organisms.
L
Cell respiration: Glucose is broken down in the
mitochondria to produce ATP , the energy currency of the
cell. This occurs through glycolysis, the citric acid cycle,
and oxidative phosphorylation.
4 .
Enzymes in cells:
4
Enzyme activity: Enzymes catalyse biochemical reactions,
lowering the activation energy required for reactions to
occur. A practical investigation might model how enzymes
function, including exploring factors like substrate
concentration and enzyme specificity.
Environmental factors affecting enzymes: Temperature,
pH, and the concentration of substrates and inhibitors
can influence enzyme activity. For example, extreme
temperatures may denature enzymes, reducing their
efficiency.
 MODULE 2
[Organisation of cells3
Inquiry question: How are cells arranged in a multicellular
organism?
Multicellular organisms are highly organised, with different
levels of structure, ranging from organelles to complete
organisms.
1
. Unicellular, colonial, and multicellular organisms:
Unicellular organisms: Consist of a single cell that
performs all life functions (e.g., bacteria, amoeba)
Colonial organisms: Groups of identical or similar cells that
live together but can survive independently (e.g., volvox).
These organisms exhibit some specialisation but do not
have the complex division of labour seen in multicellular
organisms.

Multicellular organisms: Composed of many specialised

cells that form tissues, organs, and systems, working
together to support the life of the organism (e.g., plants,
animals).
2 . Cell structure and specialisation:
Cells in multicellular organisms have specific structures
suited to their functions. For instance, muscle cells have
numerous mitochondria for energy production, while red
blood cells lack nucleus to maximise space for oxygen
transport.
.
3 Tissues, organs, and systems:
Tissues: Groups of specialised cells working together (e.g.,
muscle tissue, epithelial tissue).
Organs: Structures composed of multiple tissues working
together to perform a specific function (e.g., the heart,
liver, leaves).
Systems: Groups of organs working together to carry out
complex functions (e.g., digestive, respiratory, circulatory
system.
 Cell differentiation: The process by which cells become
specialised in multicellular organisms, such as stem cells
differentiating into various types of cells.
.
4
Hierarchical structural organisation:
)
Organelles (e.g., mitochondria, chloroplast) perform
specific function within cells.
L
Cells are the basic unit of structure and function.
Tissues consist of similar cells performing a common
function
Organs consist of multiple tissues working together.
Organ systems are groups of organs that collaborate to
perform complex body functions
Organisms are complete living entities, comprised of
many systems working in unison.

[ Nutrient and gas requirements 7

Inquiry question: what is the difference in nutrient and gas
requirements between autotrophs and heterotrophs?
Autotrophs and heterotrophs differ in how they acquire
energy and nutrients.

1. Autograph structure:
4
Dissection of plant materials: By examining plant parts
such as leaves, stems, and roots, we gain insight into their
role in supporting photosynthesis and nutrient transport.
Leaves, for example, contain specialised cells that house
chloroplasts, the organelles responsible for converting
light into chemical energy. Stems provide structural
support and house vascular tissues for transporting water
and nutrients, while roots anchor the plant and absorb
water and minerals from the soil.
 Microscopic structures: At a microscopic level, plants are
organised with intricate structures that facilitate their
functions. Chloroplasts are the site of photosynthesis,
containing chlorophyll to capture sunlight. Stomata, small
openings on the surface of leaves, regulate gas exchange
by allowing carbon dioxide in and releasing oxygen. Xylem
and phloem tissues from the vascular system, with xylem
transporting water nd minerals upwards from the roots
and phloem distributing the products of photosynthesis
throughout the plant. The structures can be visualised
using advanced imaging technologies, such as light
microscopy for general structure and electron microscopy
for detailed organelle visualisation.
2 . Function of plant structures:
Photosynthesis: study the development of glucose and
oxygen as products of photosynthesis. Investigate how
glucose is transported from leaves to other plant parts
through problem.
Gas exchange: investigate gas exchange in plants through
the stomata (openings on leaves), allowing CO2 in for
photosynthesis and O2 out as a byproduct.
.
3 Gas exchange structures in animals and plants:
Microscopic structures:
L
Alveoli in mammals: tiny air sacs in the lungs when
gas exchange takes place.
Leaf structures in plants: including stomata and
mesophyll cells where gas exchange occurs.
Macroscopic structures:
Respiratory systems in animals: investigate how
structures like the trachea, lungs, or gills facilitate gas
exchange.
Comparison of different respiratory systems in animals,
including lungs (mammals), gills (fish), and trachea
systems (insects).
4 .
Photosynthesis and theories:
Photosynthesis: evaluate how scientists developed our
understanding of photosynthesis by examining
experiments that traced the production of glucose and
oxygen in plants.
>
Transpiration-cohesion-tension theory: investigate how
water moves from the roots to leaves in plants due to
the cohesive properties of water molecules and the
tension created as water evaporates from leaves.
.
5 Digestion in mammals:
Physical digestion: breaking down food mechanically in the
mouth and stomach (e.g., chewing, stomach (hurning).
Chemical digestion: Enzymatic breakdown of complex
molecules (e.g., amylase in saliva breaking down starch).
Absorption: nutrients and water are absorbed primarily in
the small intestine, where they enter the bloodstream.
Elimination: solid waste is removed through the large
intestine and rectum.
6
eComparison of autotrophs and heterotrophs:
Autotrophs (e.g., plants, algae): require light energy to
produce organic molecules through photosynthesis. They
need CO2, water, and minerals.
Heterotrophs (e.g., animals, fungi): Obtain organic
molecules by consuming other organisms. They need
oxygen for cellular respiration to break down food
energy.
[Transport3
Inquiry question: how does the composition of the transport
medium change as it moves around an organism?

7Transport systems in animals and plants:

Macroscopic structures:
In animals: heart, blood vessels (arteries, veins,
capillaries), and the lymphatic system.
In plants: roots, stems, leaves, and vascular tissues
(xylem and phloem).
Microscopic structures:
Blood components: red and white blood cells, platelets,
and plasma.
Plant vascular system: xylem (water transport) and
phloem (sugar transport).
2 . Gas exchange in plants and animals:
Internal-external gas exchange:
Animals: oxygen isabsorbed into the bloodstream
through the alveoli in the lungs, and carbon dioxide is
expelled.
Plants: gas exchange occurs in leaves, where CO2 enters
through stomata for photosynthesis, oxygen is released.
. Comparison of transport systems:
3
L Vascular systems in plants und animals:

Plants: use xylem to transport water and minerals

from roots to leaves and phloem to transport sugars
from leaves to other parts of the plant.
LAnimals: use the circulators system to transport
oxygen, nutrients, and waste products via blood.
Open vs. Closed transport systems:
Open circulatory system: found in some invertebrates
(e.g., insects) where blood flows freely within body
cavities.
 Closed circulators system: found in vertebrates (e.g.,
mammals, birds) where blood is confined to vessels,
allowing more efficient transport.
Y . Changes in the composition of the transport medium:
In animals, blood changes composition as it moves
through different parts of the body:
Oxygenated blood is rich in oxygen when it leave
the lungs, but becomes deoxygenated after
oxygen is delivered to tissues.
Nutrients levels in blood change after food
absorption in the intestines.
L Waste products accumulate in blood after cellular
metabolism and are removed by the lungs and
kidneys.
In plants, the composition of sap changes:
Xylem sap is rich in water and minerals from the
soil, while phloem sap contains sugars produced
during photosynthesis.
 Module 3
[ Effects of the environment on organisms J
Inquiry question: how do environmental pressures promote a
change in species diversity and abundance?
Organisms in an ecosystem face both biotic (living) and
abiotic (non-living) selection pressures that affect their
survival, reproduction, and, ultimately, the populations
structure.
1 Selection pressures:
i Biotic factors: These include living organisms that affect
other ecosystems, such as predators, competition for
resources, diseases, and the availability of food.
Abiotic factors: Non-living environmental factors, such as
temperature, water availability, light, soil conditions, and
climate. These can directly affect an organisms ability to
survive and reproduce.
Changes in populations over time:
2 Example: Cane toads in Australia: The introduction of
cane toads to Australia caused significant shifts in the
ecosystem due to their toxic skin, which local predators
were not adapted to. Over time, this led to the decline of
native species and shifts in predator populations.

Example: Prickly bear distribution in Australia: The

invasive prickle bear cactus spread rapidly in Australia,
overwhelming native plant species. The introduction of
the cactus moth as a biological control reduced its
population dramatically, illustrating how a selection
pressure can change species abundance.

[Adaptation&
Inquiry question: How do adaptations increase the organisms
ability to survive
Adaptations re characteristics that enhance an organisms
ability to survive and reproduce in a specific environment.
.
1
Types of adaptations:
Structural adaptations: Physicl features of an organism
that improve survival (e.g., thick fur in artic animals for
insulation, or the long neck of a giraffe for reaching
food).
Physiological adaptations: Internl body processes that
enhance survival (e.g., desert animals producing
concentrated urine to conserve water, or plants closing
their stomata to reduce water loss.
Behavioral adaptations: Actions or behaviours that
increase an organisms chance of survival (e.g., birds
migrating to warmer regions in winter, or nocturnal
behaviour in desert animals to avoid daytime heat.
2 .
Investigating adaptations:
Practical and secondary investigations help student
explore how specific adaptations enable organisms to
thrive in their environments.
Example: Darwin's observations:
L
Finches of the galápagos islands: Darwin observed that
finch species had different beak shapes, adapted to their
specific food sources.
Australian flora and fauna: Australian organisms
exhibit unique adaptations, such as the water-
conserving abilities of plants in arid regions.

[Theory of evolution by natural selection7

Inquiry question: what is the relationship between evolution
and biodiversity?
Evolution by natural selection is the process by which species
adapt over time, leading to increased biodiversity through
the diversification of life forms.
1
.
Biological diversity and natural selection:
L
Theory of evolution by natural selection: Organisms with
traits that are better suited to their environment are
more likely to survive and reproduce, passing those
advantageous traits to future generations. Over time,
this leads to changes in species and the emergence of new
species.
L
Microevolutionary changes and speciation: Small changes
accumulate over generations, eventually leading to the
formation of new species.
Example: Evolution of the horse: Changes in body size,
limb structure, and teeth over millions of years
demonstrate how natural selection shaped modern
horses.
Example: evolution of the platypus: The platypus
evolved unique characteristics, such as a bill for
detecting prey, reflecting its adaptation to the
universe.
2 . Types of evolution:
Convergent evolution: Different species evolve similar
traits due to similar environmental pressures, despite not
sharing a common ancestor.
Example: The wings of bats and birds are an example of
convergent evolution.
L
Divergent evolution: A single species evolves into
different species due to varying environmental changes.
Example: The finches observed by Darwin on Galápagos
islands diverged into different species with distinct
beak shapes.
Punctuated Equilibrium: This theory suggests that species
remain relatively unchanged for long periods,
interrupted by short, rapid periods of evolutionary
changes, contrasting with slow, gradual changes proposed
by natural selection.
[ Evolution - the evidenceJ
Inquiry question: What is the evidence that supports the
theory of evolution by natural selection?

1 . Types of evidence:
Biochemical evidence: Dna and protein comparisons show
genetic similarities and evolutionary relationships
between species.
L)
Comparative anatomy: Structures in different species
(e.g., homologous structures like the human arm and
bat wing) suggest common ancestry.
L)
Comparative embryology: similarities in embryonic
development across different species indicate
evolutionary connections.
Biogeography: The geographic distribution of species
supports evolutionary theory, such as how species on
islands often evolve differently than their mainland
relatives.
2 .
Dating fossils:
Fossil Dating Techniques: Radiometric dating and other
techniques provide a timeline for fossil evidence, showing
a progression of evolutionary changes over millions of
years.
. Modern-day
3 examples:
Cane toad evolution: Cane toads in australia have evolved
to develop longer legs, which aid in faster colonisation of
new territories.
Antibiotic-resistant bacteria: The evolution of bacteria
resistance to antibiotics is a contemporary example of
natural selection, where bacteria with resistance genes
survive and proliferate in the presence of antibiotics.
 Module 4
[ Population dynamics ]
Inquiry question! what effect can one species have on the
other species in a community?
In an ecosystem, relationships between species and their
environment involve both biotic and abiotic factors, which
shape population dynamics and community structure.

1 Impact of abiotic factors: abiotic factors such as

temperature, light, water availability, soil composition,
and atmospheric gases play a crucial role in determining
which species can survive in a given environment. changes
in these factors can limit the distribution and abundance
of species, influencing population sizes and community
interactions.
2 .
Impact of biotic factors:
Predation: Predators regulate prey populations, helping to
maintain balance within ecosystems. A change in
predator numbers can lead to cascading effects
throughout the food web.
Competition: Species compete for limited resources, such as
food, water, or territory. This competition can lead to
competitive exclusion or resource partitioning, affecting
species abundance and diversity.
Symbiotic relationships: Organisms may enhance in
mutualistic (both species benefit), commensalistic (one
benefits, the other unaffected), or parasitic (one
benefits at the expense of the other) relationships. These
interactions shape the survival and reproductive success
of species in a community.
3 .
Ecological niches: The specific role or function a species
plays wi5in its ecosystem (its niche) is influenced by both
biotic and abiotic factors. Niche overlap often leads to
competition, whereas niche differentiation can reduce
competition and promote coexistence.
4
o Predicting consequences for populations:
L
Predation: A rise in predator numbers may cause prey
populations to decrease, altering food web dynamics.
Competition: Increased competition for resources can
reduce the population size of less competitive species.
L
Symbiosis: The loss of a mutualistic partner can threaten
the survival of dependent species.
L>
Disease: Pathogens can reduce population sizes or even
lead to extinction of species cannot develop resistance.
.
5 Measuring populations:
L
Sampling techniques: Ecologists use methods such as
quadrats, transects, and mark-recapture techniques to
estimate population sizes and monitor changes in
abundance over time.
6 .
Recent extinction event:
A recent extinction event, such as 6e extinction of the
pyrenean ibex, can be explained by a combination of
factors including habitat loss, climate change, human
activity. Extinctions disrupt ecosystem and can have far-
reaching consequences on biodiversity.

[Past ecosystemsJ
Inquiry question: How do selection pressures within an
ecosystem influence evolutionary change?
Understanding past ecosystems allows us to trace
evolutionary changes driven by environmental and selection
pressures over time.

10 Palacontological and geological evidence:

Aboriginal rock paintings: These ancient artworks provide
evidence of species that once existed in Australia’s past
ecosystems, giving insight into biodiversity and the
environmental conditions at the time.
 Rock structure and formation: By studying rock layers,
fossils, and mineral composition, geologists can
reconstruct past climates and ecosystems, offering clues
to how species and habitats have evolved.
>
Ice core drilling: Ice cores contain trapped gas bubbles
that reveal historical atmospheric compositions and
climate conditions, helping scientists understand long-
term environmental changes and their impact on
ecosystems.

2 .
Past and present technologies:
Radiometric Dating: This technique measures how the
decay of radioactive isotopes in rocks and fossils to
determine the age of ancient ecosystems and the
organisms that lived there.
L>
Gas analysis: Analysing gases trapped just rocks or ice
cores helps reconstruct the atmospheric conditions s of
the past, aiding in the understanding of climate and its
influence on evolutionary change.
o
3 Evidence of evolution:
Present-day organisms show evolutionary links to past
species, providing evidence for gradual changes shaped by
selection pressures.
Example: small mammals: Fossils of early australian
mammals show isolation and environmental pressures
led to unique adaptations, driving evolutionary changes.
Example: Sclerophyll Plants: These drough-resistant
plants evolved in response to australians dry climate,
demonstrating the influence of abiotic factors on plant
evolution.
4a Charges in past ecosystems:
Ecosystems have undergone changes over time due to
shifts in climate, biotic interactions, and geological
events. For example, lush rainforests to arid grasslands in
Aus was driven by long-term climate changes.
 Scientists evaluate hypotheses on how these changes
influenced species’ evolution and ecosystem structure.

[ Future ecosystems J
Inquiry question: How can human activity impact an
ecosystem?

1 Changes in past ecosystems to inform future management:

-
Examining past ecosystem changes, such as mass
extinction or shifts in biodiversity, helps guide the
conservation and restoration of future ecosystems.
>
Human-induced selection pressures: Activities like habitat
destruction, pollution, overhunting, and climate change
have led to the extinction of numerous species and
continue to threaten biodiversity. Understanding these
impacts can inform conservation strategies.

2 . Predicting future impacts on biodiversity:

4
Models: Scientists use ecological models to predict how
human activities, such as deforestation or climate
change, will affect future biodiversity. These models can
help shape policies aimed at mitigating effects.
Changing climate: Climate change is already altering
ecosystems, with species shifting their ranges, altering
migration patterns, and facing increased extinction risks.
Understanding these changes is critical to managing
ecosystems in the future.

. Restoring
3 damaged ecosystems:
Mining sites: Restoration practices at former mining sites
include replanting native species, restoring soil health, and re-
establishing natural water flows.
L Land degradation from agricultural practices: Sustainable farming
methods are used to restore degraded agricultural land. Restoring
ecosystems help rebuild biodiversity, improve soil & water health, &
provide ecosystem service like carbon sequestration.
 know everything
Quadrat &

plant animal cells + tissues

Radiometric dating
movement of materials in cells
charles darwin

evolution

enzymes

Xylem +
phloem

circulatory system
microscopes

adaptations

graphing