Biology (Version 8.4)

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Unit 1
Unit 2
Unit 3
Unit 4

Understand how Biology works

Rationale/Aims

Biology is the study of the fascinating diversity of life as it has evolved and as it interacts and functions. Investigation of biological systems and their interactions, from cellular processes to ecosystem dynamics, has led to biological knowledge and understanding that enable us to explore and explain everyday observations, find solutions to biological issues, and understand the processes of biological continuity and change over time.

Structure of Biology

Links to Foundation to Year 10

The senior secondary Biology curriculum continues to develop student understanding and skills from across the three strands of the F-10 Australian Curriculum: Science. In the Science Understanding strand, the Biology curriculum draws on knowledge and understanding from across the four sub-strands of Biological, Physical, Chemical, and Earth and Space sciences.

Representation of Cross-curriculum Priorities

While the significance of the cross-curriculum priorities for Biology varies, there are opportunities for teachers to select contexts that incorporate the key concepts from each priority.

Achievement standards

Unit 1: Biodiversity and the interconnectedness of life

Unit 1: Biodiversity and the interconnectedness of life Description

The current view of the biosphere as a dynamic system composed of Earth’s diverse, interrelated and interacting ecosystems developed from the work of eighteenth and nineteenth century naturalists, who collected, classified, measured and mapped the distribution of organisms and environments around the world. In this unit, students investigate and describe a number of diverse ecosystems, exploring the range of biotic and abiotic components to understand the dynamics, diversity and underlying unity of these systems.

Students develop an understanding of the processes involved in the movement of energy and matter in ecosystems. They investigate ecosystem dynamics, including interactions within and between species, and interactions between abiotic and biotic components of ecosystems. They also investigate how measurements of abiotic factors, population numbers and species diversity, and descriptions of species interactions, can form the basis for spatial and temporal comparisons between ecosystems. Students use classification keys to identify organisms, describe the biodiversity in ecosystems, investigate patterns in relationships between organisms, and aid scientific communication.

Through the investigation of appropriate contexts, students explore how international collaboration, evidence from multiple disciplines and the use of ICT and other technologies have contributed to the study and conservation of national, regional and global biodiversity. They investigate how scientific knowledge is used to offer valid explanations and reliable predictions, and the ways in which scientific knowledge interacts with social, economic, cultural and ethical factors.

Fieldwork is an important part of this unit, providing valuable opportunities for students to work together to collect first-hand data and to experience local ecosystem interactions. In order to understand the interconnectedness of organisms, the physical environment and human activity, students analyse and interpret data collected through investigation of a local environment and from sources relating to other Australian, regional and global environments.

Unit 1: Biodiversity and the interconnectedness of life Learning Outcomes

By the end of this unit, students:

understand how classification helps to organise, analyse and communicate data about biodiversity
understand that ecosystem diversity and dynamics can be described and compared with reference to biotic and abiotic components and their interactions
understand how theories and models have developed based on evidence from multiple disciplines; and the uses and limitations of biological knowledge in a range of contexts
use science inquiry skills to design, conduct, evaluate and communicate investigations into biodiversity and flows of matter and energy in a range of ecosystems
evaluate, with reference to empirical evidence, claims about relationships between and within species, diversity of and within ecosystems, and energy and matter flows
communicate biological understanding using qualitative and quantitative representations in appropriate modes and genres.

Unit 1: Biodiversity and the interconnectedness of life Content Descriptions

Science Inquiry Skills (Biology Unit 1)

Identify, research and construct questions for investigation; propose hypotheses; and predict possible outcomes (ACSBL001)

Design investigations, including the procedure/s to be followed, the materials required, and the type and amount of primary and/or secondary data to be collected; conduct risk assessments; and consider research ethics, including animal ethics (ACSBL002)

Conduct investigations, including using ecosystem surveying techniques, safely, competently and methodically for the collection of valid and reliable data (ACSBL003)

Represent data in meaningful and useful ways; organise and analyse data to identify trends, patterns and relationships; qualitatively describe sources of measurement error, and uncertainty and limitations in data; and select, synthesise and use evidence to make and justify conclusions (ACSBL004)

Interpret a range of scientific and media texts, and evaluate processes, claims and conclusions by considering the quality of available evidence; and use reasoning to construct scientific arguments (ACSBL005)

Select, construct and use appropriate representations, including classification keys, food webs and biomass pyramids, to communicate conceptual understanding, solve problems and make predictions (ACSBL006)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSBL007)

Science as a Human Endeavour (Units 1 and 2)

Science is a global enterprise that relies on clear communication, international conventions, peer review and reproducibility (ACSBL008)

Development of complex models and/or theories often requires a wide range of evidence from multiple individuals and across disciplines (ACSBL009)

Advances in science understanding in one field can influence other areas of science, technology and engineering (ACSBL010)

The use of scientific knowledge is influenced by social, economic, cultural and ethical considerations (ACSBL011)

The use of scientific knowledge may have beneficial and/or harmful and/or unintended consequences (ACSBL012)

Scientific knowledge can enable scientists to offer valid explanations and make reliable predictions (ACSBL013)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSBL014)

Science Understanding

Describing biodiversity

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Technology as a tool to measure, analyse and monitor biodiversity

Developments in software, computing and supercomputing have been important in ecological classification as they have enabled scientists to classify regions according to large sets of biotic and abiotic data and to compare data over time (ACSBL010). Supercomputers have also enabled the development of large, complex models to analyse species data collected from multiple individuals in a range of locations, and to infer relationships between species, including their shared evolutionary past (ACSBL009). Advances in remote sensing radar imagery and satellite tracking in real time have enabled scientists to measure and monitor populations and play a significant role in surveying and monitoring large or inaccessible ecosystems.

International biodiversity protection

International agreements about biodiversity protection, such as the World Heritage Convention, are based on the premise that local, regional and international biodiversity represent a global resource, vital for human survival, that should be maintained for future generations (ACSBL008). The World Heritage Convention is designed to ensure the protection of natural and cultural heritage and encourage international cooperation in the conservation of biodiversity. Sites are selected as natural World Heritage based on a range of criteria, including, but not limited to, conservation of biodiversity (ACSBL011). Selected sites are monitored to ensure continued integrity, protection and management, including evaluation of projected economic, social and environmental impacts on the site (ACSBL014). Within the international scientific community, methods and findings related to biodiversity monitoring and analysis are shared through peer reviewed articles in international journals (ACSBL014).

Biodiversity targets

Setting agreed biodiversity targets has been proposed as one way to achieve positive international action towards biodiversity conservation and encourage accountability (ACSBL008). Setting such targets requires a broad range of scientific knowledge in gathering data, identifying indicators and ensuring that measurement is valid and reliable and will inform improved ecosystem management (ACSBL009). The 2010 Biodiversity Target was endorsed by the World Summit on Sustainable Development and aimed to achieve a significant reduction in the rate of biodiversity loss at global, regional and national levels. Measurement of attainment of this target required international agreement regarding baseline data, acceptable timescales, acceptable rates and appropriate measures for monitoring and evaluating the rate of biodiversity loss (ACSBL008).

Biodiversity includes the diversity of species and ecosystems; measures of biodiversity rely on classification and are used to make comparisons across spatial and temporal scales (ACSBL015)

Biological classification is hierarchical and based on different levels of similarity of physical features, methods of reproduction and molecular sequences (ACSBL016)

Biological classification systems reflect evolutionary relatedness between groups of organisms (ACSBL017)

Most common definitions of species rely on morphological or genetic similarity or the ability to interbreed to produce fertile offspring in natural conditions – but, in all cases, exceptions are found (ACSBL018)

Ecosystems are diverse, composed of varied habitats and can be described in terms of their component species, species interactions and the abiotic factors that make up the environment (ACSBL019)

Relationships and interactions between species in ecosystems include predation, competition, symbiosis and disease (ACSBL020)

In addition to biotic factors, abiotic factors including climate and substrate can be used to describe and classify environments (ACSBL021)

Ecosystem dynamics

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Indigenous knowledge of ecosystem interactions and change

Indigenous knowledge of environmental change and interactions between abiotic and biotic elements of ecosystems in local contexts has developed over thousands of years and provides valuable data for understanding ecosystem dynamics (ACSBL009). Some Indigenous knowledge is represented in Indigenous art and can include evidence of past biodiversity and climate change that supports data from the fossil record. Indigenous knowledge also includes land management practices that can maintain ecosystems at specific successional points. These practices are often used to complement practices in conservation areas, where land management decisions reflect scientific, social, cultural and ethical considerations (ACSBL011).

Marine reserves

Southeast Asia is a global epicentre for marine diversity; the establishment of marine reserves aims to contribute to the long-term conservation of marine ecosystems and protect marine biodiversity. Identification and classification of marine reserve areas requires consideration of enforcement logistics, the multiple uses of the area (for example, fishing, recreation, tourism), indigenous peoples’ usage rights, and the extent of the area required to contribute to local and global biodiversity conservation (ACSBL011). Scientific knowledge based on local data collection and analysis, computer simulation of future scenarios and analysis of analogous scenarios is required to analyse these factors, classify areas and predict the likelihood that the reserve will successfully protect marine biodiversity (ACSBL013).

Keystone species and conservation

The concept of a keystone species, a species that is particularly important in maintaining the structure of an ecological community, was first introduced by Robert T Paine in the late 1960s. Data supporting the theory has been collected by a large number of scientists from across a wide range of ecosystems and for a wide range of species (ACSBL009). Some biologists have advocated for keystone species to be special targets for conservation efforts and keystone species theory has informed many conservation strategies. However there are differing views about the effectiveness of single-species conservation (such as keystone species, flagship species or umbrella species) in maintaining complex ecosystem dynamics (ACSBL012).

The biotic components of an ecosystem transfer and transform energy originating primarily from the sun to produce biomass, and interact with abiotic components to facilitate biogeochemical cycling, including carbon and nitrogen cycling; these interactions can be represented using food webs, biomass pyramids, water and nutrient cycles (ACSBL022)

Species or populations, including those of microorganisms, fill specific ecological niches; the competitive exclusion principle postulates that no two species can occupy the same niche in the same environment for an extended period of time (ACSBL023)

Keystone species play a critical role in maintaining the structure of the community; the impact of a reduction in numbers or the disappearance of keystone species on an ecosystem is greater than would be expected based on their relative abundance or total biomass (ACSBL024)

Ecosystems have carrying capacities that limit the number of organisms (within populations) they support, and can be impacted by changes to abiotic and biotic factors, including climatic events (ACSBL025)

Ecological succession involves changes in the populations of species present in a habitat; these changes impact the abiotic and biotic interactions in the community, which in turn influence further changes in the species present and their population size (ACSBL026)

Ecosystems can change dramatically over time; the fossil record and sedimentary rock characteristics provide evidence of past ecosystems and changes in biotic and abiotic components (ACSBL027)

Human activities (for example, over-exploitation, habitat destruction, monocultures, pollution) can reduce biodiversity and can impact on the magnitude, duration and speed of ecosystem change (ACSBL028)

Models of ecosystem interactions (for example, food webs, successional models) can be used to predict the impact of change and are based on interpretation of and extrapolation from sample data (for example, data derived from ecosystem surveying techniques); the reliability of the model is determined by the representativeness of the sampling (ACSBL029)

Unit 2: Cells and multicellular organisms

Unit 2: Cells and multicellular organisms Description

The cell is the basic unit of life. Although cell structure and function are very diverse, all cells possess some common features: all prokaryotic and eukaryotic cells need to exchange materials with their immediate external environment in order to maintain the chemical processes vital for cell functioning. In this unit, students examine inputs and outputs of cells to develop an understanding of the chemical nature of cellular systems, both structurally and functionally, and the processes required for cell survival. Students investigate the ways in which matter moves and energy is transformed and transferred in the biochemical processes of photosynthesis and respiration, and the role of enzymes in controlling biochemical systems.

Multicellular organisms typically consist of a number of interdependent systems of cells organised into tissues, organs and organ systems. Students examine the structure and function of plant and animal systems at cell and tissue levels in order to describe how they facilitate the efficient provision or removal of materials to and from all cells of the organism.

Through the investigation of appropriate contexts, students explore how international collaboration, evidence from multiple disciplines and the use of ICT and other technologies have contributed to developing understanding of the structure and function of cells and multicellular organisms. They investigate how scientific knowledge is used to offer valid explanations and reliable predictions, and the ways in which scientific knowledge interacts with social, economic, cultural and ethical factors.

Students use science inquiry skills to explore the relationship between structure and function, by conducting real or virtual dissections and carrying out microscopic examination of cells and tissues. Students consider the ethical considerations that apply to the use of living organisms in research. They develop skills in constructing and using models to describe and interpret data about the functions of cells and organisms.

Unit 2: Cells and multicellular organisms Learning Outcomes

By the end of this unit, students:

understand that the structure and function of cells and their components are related to the need to exchange matter and energy with their immediate environment
understand that multicellular organisms consist of multiple interdependent and hierarchically-organised systems that enable exchange of matter and energy with their immediate environment
understand how theories and models have developed based on evidence from multiple disciplines; and the uses and limitations of biological knowledge in a range of contexts
use science inquiry skills to design, conduct, evaluate and communicate investigations into the structure and function of cells and multicellular organisms
evaluate, with reference to empirical evidence, claims about cellular processes and the structure and function of multicellular organisms
communicate biological understanding using qualitative and quantitative representations in appropriate modes and genres.

Unit 2: Cells and multicellular organisms Content Descriptions

Science Inquiry Skills (Biology Unit 2)

Identify, research and construct questions for investigation; propose hypotheses; and predict possible outcomes (ACSBL030)

Conduct investigations, including microscopy techniques, real or virtual dissections and chemical analysis, safely, competently and methodically for the collection of valid and reliable data (ACSBL032)

Select, construct and use appropriate representations, including diagrams of structures and processes; and images from different imaging techniques, to communicate conceptual understanding, solve problems and make predictions (ACSBL035)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSBL036)

Science as a Human Endeavour (Units 1 and 2)

Science is a global enterprise that relies on clear communication, international conventions, peer review and reproducibility (ACSBL037)

Development of complex models and/or theories often requires a wide range of evidence from multiple individuals and across disciplines (ACSBL038)

Advances in science understanding in one field can influence other areas of science, technology and engineering (ACSBL039)

The use of scientific knowledge is influenced by social, economic, cultural and ethical considerations (ACSBL040)

The use of scientific knowledge may have beneficial and/or harmful and/or unintended consequences (ACSBL041)

Scientific knowledge can enable scientists to offer reliable explanations and make reliable predictions (ACSBL042)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSBL043)

Science Understanding

Cells as the basis of life

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Stem cell research

Embryonic stem cells have the potential to be grown into specialised cells and could enable the repair or replacement of ailing organs and tissues. In the late 1990s, stem cells were successfully removed from available embryos at fertility clinics and the world’s first embryonic stem cell line was established (ACSBL037), prompting excitement in the international scientific community and concern in religious and political circles. Concerns about the potential for unethical human experimentation has prompted some governments to prohibit some types of stem cell research, or to limit government funding for it (ACSBL040). International groups such as the International Society for Stem Cell Research have convened experts in science, ethics and law to develop guidelines for human embryonic stem cell research, with the aim of promoting transparent and uniform practice worldwide (ACSBL037).

Photosynthesis and productivity

Photosynthesis is one of the most important biological processes on Earth but it is quite inefficient; researchers report that natural trade-offs result in very low efficiency in many important food crops. Research is currently underway to engineer or enhance photosynthesis to improve food and fuel production. This includes the development of artificial leaves that convert solar energy to a liquid fuel via a process similar to photosynthesis, and investigation of combining more efficient algal photosynthesis with plant photosynthesis to improve crop productivity (ACSBL041). These advances have the potential to decrease reliance of fossil fuels and improve agricultural sustainability (ACSBL043).

Cell membrane model development

From the nineteenth century it was accepted that some form of semi-permeable barrier must exist around a cell, although there was no evidence to indicate its structure. Various scientists, including Traube, Quincke, Fricke and Gorter and Grendel, contributed to the theory that the cell membrane was composed of a lipid bilayer, and in the 1950s the use of electron microscopy confirmed these results through direct investigation of the membrane (ACSBL039). The first model of the membrane to incorporate the notion of fluidity was proposed by Mueller and Rudin in the 1960s, and it was demonstrated conclusively by Frye and Edidin in 1970. The results of this experiment were used by Singer and Nicolson as evidence for their 1972 proposal of the fluid mosaic model of the cell membrane (ACSBL038). Ongoing research continues to refine this model, such as research into the structure of channel proteins in the membrane (ACSBL038).

Cells require inputs of suitable forms of energy, including light energy or chemical energy in complex molecules, and matter, including gases, simple nutrients, ions, and removal of wastes, to survive (ACSBL044)

The cell membrane separates the cell from its surroundings and controls the exchange of materials, including gases, nutrients and wastes, between the cell and its environment (ACSBL045)

Movement of materials across membranes occurs via diffusion, osmosis, active transport and/or endocytosis (ACSBL046)

Factors that affect exchange of materials across membranes include the surface-area-to-volume ratio of the cell, concentration gradients, and the physical and chemical nature of the materials being exchanged (ACSBL047)

Prokaryotic and eukaryotic cells have many features in common, which is a reflection of their common evolutionary past, but prokaryotes lack internal membrane bound organelles, do not have a nucleus, are significantly smaller than eukaryotes, usually have a single circular chromosome, and exist as single cells (ACSBL048)

In eukaryotic cells, specialised organelles facilitate biochemical processes of photosynthesis, cellular respiration, the synthesis of complex molecules (including carbohydrates, proteins, lipids and other biomacromolecules), and the removal of cellular products and wastes (ACSBL049)

Biochemical processes in the cell are controlled by the nature and arrangement of internal membranes, the presence of specific enzymes, and environmental factors (ACSBL050)

Enzymes have specific functions, which can be affected by factors including temperature, pH, the presence of inhibitors, and the concentrations of reactants and products (ACSBL051)

Photosynthesis is a biochemical process that in plant cells occurs in the chloroplast and that uses light energy to synthesise organic compounds; the overall process can be represented as a balanced chemical equation (ACSBL052)

Cellular respiration is a biochemical process that occurs in different locations in the cytosol and mitochondria and metabolises organic compounds, aerobically or anaerobically, to release useable energy in the form of ATP; the overall process can be represented as a balanced chemical equation (ACSBL053)

Multicellular organisms

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Animal ethics

The use of animals in research has played an important role in furthering scientific understanding of the structure and function of multicellular organisms and the mechanisms of medical interventions. Ethical treatment of animals as sentient, feeling beings has been accepted as a global principle in research and the three strategies of replacement, reduction and refinement form the basis of many international guidelines (ACSBL037). Replacement is defined as the substitution for conscious living higher animals of insentient material, such as through use of tissue culture techniques; reduction involves using only the minimum number of animals needed to meet statistical requirements; and refinement involves decreasing the severity of the impact of the procedure on any animals that have to be used. These strategies are based on scientific research and have been devised to inform sustainable ethical use of animals in research (ACSBL043).

Organ and tissue transplantation

Modern surgical techniques have made it possible for diseased or damaged organs to be replaced by healthy ones from a living or dead donor. Improvements in technologies to store and transport living tissue and the development of immunosuppressive drugs to decrease rejection by transplant recipients have led to increasing numbers of people benefiting from organ and tissue transplants (ACSBL039). However the increased demand for transplantation has also led to illegal organ and tissue trafficking, forced donation and ‘transplantation tourism’, where individuals travel to other countries where it is easier or cheaper to obtain a transplant. These situations may involve violation of human rights and exploitation of the poor, and pose many ethical concerns (ACSBL041).

Bioartificial organs

There is a demand for bioartificial tissues and organs as an alternative to donor organs or tissues, which are in short supply and may be rejected by the recipient’s body (ACSBL040). To design bioartificial organs, scientists use knowledge of the structure and function of organs to design a scaffold and populate it with functional tissue. Healthy cells from the patient’s diseased organ are extracted and grown on the scaffold, with cells applied in layers to encourage them to form tissues. If the patient’s own cells are too badly damaged, organs could be grown using cells from a stem cell bank. Developments in this area could lead to a future in which surgeons would order organs to be grown as needed, removing the need to wait for donors whose organs and tissues might not be a perfect match to the recipient (ACSBL042).

Multicellular organisms have a hierarchical structural organisation of cells, tissues, organs and systems (ACSBL054)

The specialised structure and function of tissues, organs and systems can be related to cell differentiation and cell specialisation (ACSBL055)

In animals, the exchange of gases between the internal and external environments of the organism is facilitated by the structure and function of the respiratory system at cell and tissue levels (ACSBL056)

In animals, the exchange of nutrients and wastes between the internal and external environments of the organism is facilitated by the structure and function of the cells and tissues of the digestive system (for example, villi structure and function), and the excretory system (for example, nephron structure and function) (ACSBL057)

In animals, the transport of materials within the internal environment for exchange with cells is facilitated by the structure and function of the circulatory system at cell and tissue levels (for example, the structure and function of capillaries) (ACSBL058)

In plants, gases are exchanged via stomata and the plant surface; their movement within the plant by diffusion does not involve the plant transport system (ACSBL059)

In plants, transport of water and mineral nutrients from the roots occurs via xylem involving root pressure, transpiration and cohesion of water molecules; transport of the products of photosynthesis and some mineral nutrients occurs by translocation in the phloem (ACSBL060)

Unit 3: Heredity and continuity of life

Unit 3: Heredity and continuity of life Description

Heredity is an important biological principle as it explains why offspring (cells or organisms) resemble their parent cell or organism. Organisms require cellular division and differentiation for growth, development, repair and sexual reproduction. In this unit, students investigate the biochemical and cellular systems and processes involved in the transmission of genetic material to the next generation of cells and to offspring. They consider different patterns of inheritance by analysing the possible genotypes and phenotypes of offspring. Students link their observations to explanatory models that describe patterns of inheritance, and explore how the use of predictive models of inheritance enables decision making.

Students investigate the genetic basis for the theory of evolution by natural selection through constructing, using and evaluating explanatory and predictive models for gene pool diversity of populations. They explore genetic variation in gene pools, selection pressures and isolation effects in order to explain speciation and extinction events and to make predictions about future changes to populations.

Through the investigation of appropriate contexts, students explore the ways in which models and theories related to heredity and population genetics, and associated technologies, have developed over time and through interactions with social, cultural, economic and ethical considerations. They investigate the ways in which science contributes to contemporary debate about local, regional and international issues, including evaluation of risk and action for sustainability, and recognise the limitations of science to provide definitive answers in different contexts.

Students use science inquiry skills to design and conduct investigations into how different factors affect cellular processes and gene pools; they construct and use models to analyse the data gathered; and they continue to develop their skills in constructing plausible predictions and valid, reliable conclusions.

Unit 3: Heredity and continuity of life Learning Outcomes

By the end of this unit, students:

understand the cellular processes and mechanisms that ensure the continuity of life, and how these processes contribute to unity and diversity within a species
understand the processes and mechanisms that explain how life on Earth has persisted, changed and diversified over the last 3.5 billion years
understand how models and theories have developed over time; and the ways in which biological knowledge interacts with social, economic, cultural and ethical considerations in a range of contexts
use science inquiry skills to design, conduct, evaluate and communicate investigations into heredity, gene technology applications, and population gene pool changes
evaluate with reference to empirical evidence, claims about heredity processes, gene technology, and population gene pool processes, and justify evaluations
communicate biological understanding using qualitative and quantitative representations in appropriate modes and genres.

Unit 3: Heredity and continuity of life Content Descriptions

Science Inquiry Skills (Biology Unit 3)

Identify, research and construct questions for investigation; propose hypotheses; and predict possible outcomes (ACSBL061)

Conduct investigations, including the use of probabilities to predict inheritance patterns, real or virtual gel electrophoresis, and population simulations to predict population changes, safely, competently and methodically for the collection of valid and reliable data (ACSBL063)

Represent data in meaningful and useful ways, including the use of mean, median, range and probability; organise and analyse data to identify trends, patterns and relationships; discuss the ways in which measurement error, instrumental accuracy, the nature of the procedure and the sample size may influence uncertainty and limitations in data; and select, synthesise and use evidence to make and justify conclusions (ACSBL064)

Interpret a range of scientific and media texts, and evaluate models, processes, claims and conclusions by considering the quality of available evidence, including interpreting confidence intervals in secondary data; and use reasoning to construct scientific arguments (ACSBL065)

Select, construct and use appropriate representations, including models of DNA replication, transcription and translation, Punnett squares and probability models of expression of a specific gene in a population, to communicate conceptual understanding, solve problems and make predictions (ACSBL066)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSBL067)

Science as a Human Endeavour (Units 3 & 4)

ICT and other technologies have dramatically increased the size, accuracy and geographic and temporal scope of data sets with which scientists work (ACSBL068)

Models and theories are contested and refined or replaced when new evidence challenges them, or when a new model or theory has greater explanatory power (ACSBL069)

The acceptance of scientific knowledge can be influenced by the social, economic and cultural context in which it is considered (ACSBL070)

People can use scientific knowledge to inform the monitoring, assessment and evaluation of risk (ACSBL071)

Science can be limited in its ability to provide definitive answers to public debate; there may be insufficient reliable data available, or interpretation of the data may be open to question (ACSBL072)

International collaboration is often required when investing in large-scale science projects or addressing issues for the Asia-Pacific region (ACSBL073)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSBL074)

Science Understanding

DNA, genes and the continuity of life

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Bioinformatics

Bioinformatics involves the construction, maintenance and use of databases to analyse the relationships in biological data, such as amino acid sequences or nucleotide sequences (ACSBL068). DNA and protein sequences can be mapped and analysed to compare genes within a species or between different species. One example of a bioinformatics project is the Human Genome Project, an international, collaborative research project which resulted in the publication of the full sequence of the human genome in 2003 (ACSBL073). The project was completed ahead of schedule, largely as a result of widespread international cooperation and advances in genomics and computing. The databases associated with the project are freely available via the internet, and this data is used extensively by the international scientific community.

A $1000 genome

A number of companies have announced that individuals will soon be able to access full genome sequencing for roughly $1000, enabling many more people to identify whether they have gene variants associated with genetic disease (ACSBL071). One potential application of this technology is the sequencing of all babies at birth, in order to enable doctors to identify genetic conditions and structure individualised healthcare, dietary and exercise regimes that will lead to better health. However there is significant concern about the risks in making this data so readily available, and the privacy issues regarding ownership and availability of sequences. Many groups are calling for safeguards to be implemented before whole genome sequencing becomes widespread, including legislation to protect personal privacy, regardless of how the sample was obtained (ACSBL070).

Genetically modified organisms

Genetic engineering to insert genes responsible for specific traits into plant and animal DNA is seen by some scientists as the next wave of advancement in agriculture, with the potential to increase crop yields and provide ways to grow crops on degraded lands (ACSBL074). A wide range of transgenic crops is currently on the market, some having been engineered to resist pesticides, insects and disease. Work is also underway on transgenic animals with engineered traits such as faster growth and the ability to produce pharmaceuticals. Critics fear that genetically engineered products are being rushed to market before their effects are fully understood. Concerns include possible health risks to consumers and the long term ecological impact of releasing engineered organisms into the environment, including the effects on non-target organisms, a speeding of the evolution of pesticide-resistant pest species, and the possibility of gene flow from crop species to weed species resulting in the emergence of ‘super weeds’ (ACSBL072).

Continuity of life requires the replication of genetic material and its transfer to the next generation through processes including binary fission, mitosis, meiosis and fertilisation (ACSBL075)

DNA is a helical double-stranded molecule that occurs bound to proteins in chromosomes in the nucleus, and as unbound circular DNA in the cytosol of prokaryotes and in the mitochondria and chloroplasts of eukaryotic cells (ACSBL076)

The structural properties of the DNA molecule, including nucleotide composition and pairing and the weak bonds between strands of DNA, allow for replication (ACSBL077)

Genes include ‘coding’ and ‘non-coding’ DNA, and many genes contain information for protein production (ACSBL078)

Protein synthesis involves transcription of a gene into messenger RNA in the nucleus, and translation into an amino acid sequence at the ribosome (ACSBL079)

Proteins, including enzymes, are essential to cell structure and functioning (ACSBL080)

The phenotypic expression of genes depends on factors controlling transcription and translation during protein synthesis, the products of other genes, and the environment (ACSBL081)

Mutations in genes and chromosomes can result from errors in DNA replication or cell division, or from damage by physical or chemical factors in the environment (ACSBL082)

Differential gene expression controls cell differentiation for tissue formation, as well as the structural changes that occur during growth (ACSBL083)

Variations in the genotype of offspring arise as a result of the processes of meiosis and fertilisation, as well as a result of mutations (ACSBL084)

Frequencies of genotypes and phenotypes of offspring can be predicted using probability models, including Punnett squares, and by taking into consideration patterns of inheritance, including the effects of dominant, autosomal and sex-linked alleles and multiple alleles, and polygenic inheritance (ACSBL085)

DNA sequencing enables mapping of species genomes; DNA profiling identifies the unique genetic makeup of individuals (ACSBL086)

Biotechnology can involve the use of bacterial enzymes, plasmids as vectors, and techniques including gel electrophoresis, bacterial transformations and PCR (ACSBL087)

Continuity of life on Earth

Examples in context

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

Evidence for evolution

Darwin proposed the theory of evolution by natural selection to refute Lamarck’s theory. He provided evidence for descent with modification (branching evolution) based on patterns in variation of domesticated and wild species, and patterns of species distributions in time and space (ACSBL069). Contemporary evidence for evolution comes from five main lines of evidence: paleontology, biogeography, developmental biology, morphology and genetics. Technological developments in the fields of comparative genomics, comparative biochemistry and bioinformatics have enabled identification of further evidence for evolutionary relationships (ACSBL068).

Human evolution – are we still evolving?

Theoretical models of natural selection do not account for culture and technology, which can alter selection pressures so that it is not necessarily the ‘fittest’ that survive to reproduce. This has caused some to ask whether human evolution is still occurring, particularly in Western societies post the significant cultural events of agriculture, the Industrial Revolution, modern medicine and mass transportation. However, new results from projects such as the 1000 Genomes Project indicate that the rapid increase in the human population (from roughly five million at the end of the last Ice Age to more than seven billion today) has generated an enormous amount of variation in the species (ACSBL068). Other localised studies point to fertility-related natural selection (ACSBL069).

Sustainable population size and reserve area

The notion of minimum reserve size to maintain ecological processes is an important focus of conservation planning, and includes consideration of biogeography and population dynamics. Estimating minimum reserve size for a target conservation species can involve the calculation of minimum viable population and consideration of the area required for each individual in that population, given species preferences for particular habitat and social dynamics within the population (ACSBL074). However, determination of reserve size must also consider the needs and attitudes of other stakeholders, including cultural and economic values of indigenous peoples, recreational and aesthetic values of the public, the capacity to protect, monitor and manage the reserve, and other factors (ACSBL070). An alternative to single large reserves may be a number of smaller reserves that are connected by ‘green corridors’ that enable fauna to migrate.

Life has existed on Earth for approximately 3.5 billion years and has changed and diversified over time (ACSBL088)

Comparative genomics provides evidence for the theory of evolution (ACSBL089)

Natural selection occurs when selection pressures in the environment confer a selective advantage on a specific phenotype to enhance its survival and reproduction; this results in changes in allele frequency in the gene pool of a population (ACSBL090)

In additional to environmental selection pressures, mutation, gene flow and genetic drift can contribute to changes in allele frequency in a population gene pool and results in micro-evolutionary change (ACSBL091)

Mutation is the ultimate source of genetic variation as it introduces new alleles into a population (ACSBL092)

Speciation and macro-evolutionary changes result from an accumulation of micro-evolutionary changes over time (ACSBL093)

Differing selection pressures between geographically isolated populations may lead to allopatric speciation (ACSBL094)

Populations with reduced genetic diversity face increased risk of extinction (ACSBL095)