Level 7: Human biology
Focus statements for human biology
- How a human being is “organised” – the life processes at the organism level.
- The human organism is composed of cells.
- How can DNA control the life processes?
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Focus question 1: How do humans carry out their life processes at the organism level?
Students consider how:
- human organ systems within the body work together in a coordinated way
- human organ systems are affected by their internal and external environment.
Possible investigations
- How and why do pulse and breathing rates change with exercise? (Collecting and processing data in the context of gas exchange.)
- Why can’t I hold my breath for very long? (Biological systems are integrated and co-ordinated to ensure the organism’s survival.)
- Investigate reaction time as an indicator of the interdependence of nervous and skeletomuscular systems. How does tiredness affect my driving?
- Agar blocks can be used as a model to explore the relationship between surface-area-to-volume ratio and the efficiency of diffusion. (Scientists use models to investigate ideas.)
- What is the effect of altitude training on athletes who are preparing for a strenuous event such as a marathon or rugby test match?
- How are Tibetans and Andeans differently adapted to high-altitude living?
Possible assessments
- AS91153 Biology 2.1: Carry out a practical investigation in a biology context, with supervision (4 credits, internal)
- AS91155 Biology 2.3: Demonstrate understanding of adaptation of plants and animals to their way of life (3 credits, internal)
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Focus question 2: How do humans carry out their life processes at the cellular level?
Students consider how:
- life processes at the cell level involve inputs and outputs and are affected by a range of internal and external factors
- the structure of, and internal organisation of, a cell enables cellular processes to proceed efficiently
- cells differ in their structure and internal organisation, depending on their specific functions
- DNA replication and mitosis are stages in the regular cell cycle.
Possible investigations
- Use a respirometer to investigate the effect of temperature on the respiration rate of a model organism such as a slater. (Scientists use models to test ideas and extend understanding.)
- Why do the cells lining the small intestine have microvilli, while cells lining the mouth do not? (Scientists ask questions to extend their understanding.)
- How are stem cells different from other cells? How could stem cells be used to improve human health? (Exploring the socio-scientific issues concerning the use of stem cells.)
- Use a microscope to examine and compare the vessel walls of veins and arteries in terms of the specific function of each tissue. (Using scientific conventions to communicate via biological drawings.)
- Prepare slides of onion root cells and observe the stages of mitosis through a microscope. (Using scientific conventions to communicate via biological drawings.)
- Construct a model to demonstrate the role of actin and myosin in muscle fibre cells. (Scientists use models to test ideas and extend their understanding.)
Possible assessments
- AS91153 Biology 2.1: Carry out a practical investigation in a biology context, with supervision (4 credits, internal)
- AS91154 Biology 2.2: Analyse the biological validity of information presented to the public (3 credits, internal)
- AS91156 Biology 2.4: Demonstrate understanding of life processes at the cellular level (4 credits, external)
- AS91160 Biology 2.8: Investigate biological material at the microscopic level (3 credits, internal)
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Focus question 3: How do humans carry out their life processes at the gene/DNA level?
Students consider:
- The comparative structure of DNA, RNA, and proteins, and the processes of transcription and translation.
- The structure of proteins determines their structural, enzymic, and regulatory roles.
- Environmental factors may act as mutagens.
- A base mutation may affect the composition of a polypeptide chain.
- Metabolic pathways involve a series of enzyme-catalysed steps.
- The environment interacts with the genotype to produce the phenotype.
- What are the predictable outcomes of monohybrid crosses involving a range of allele interactions (for example, co-dominance, lethal alleles, multiple alleles).
- What are the predictable outcomes of dihybrid crosses involving complete dominance.
- What is the effect of crossing over and linked genes on phenotypic ratios.
- Mutations and sexual recombination both provide variation within the gene pool of a population.
- Factors such as natural selection, migration, and genetic drift are responsible for observed changes in allele frequency in a population.
Possible investigations
- Convert a hypothetical DNA sequence into a polypeptide using a codon table. (Scientists use specific vocabulary and techniques to explain their observations.)
- Predict the possible effects of a base mutation in DNA on the resulting protein – for example, the CF mutation in humans. (Scientists make predictions based on their current understanding.)
- Research the various types of protein and their related structural, enzymic, and regulatory roles.
- Research the role of New Zealander Maurice Wilkins in the discovery of the structure of DNA. (Science is a collaborative effort and new evidence leads to changes in science ideas.)
- Construct paper models of individual nucleotide monomers and assemble them into a class model of a DNA polymer. (Use of scientific models to extend understanding.)
- A health nurse explains the Guthrie card test for newborn babies. (New scientific knowledge can be applied to human problems.)
- How do I feel about having my DNA (Guthrie card sample) kept on record indefinitely? (New scientific knowledge frequently generates ethical issues.)
- What causes albinism in humans? Explain in terms of a metabolic pathway.
- What is meant by “essential” amino acids and how do they feature in a healthy human diet?
- Why do humans get scurvy but monkeys don’t?
- Investigate the incidence of lactose intolerance in different ethnic groups.
- Nature versus nurture: explore the data from identical-twin studies.
- Collect data on the incidence of colour-blindness in men and women. Explain.
- Culture Drosophila flies (as a model organism) to trace sex-linked traits through successive generations.
- Model crossing over using pipe cleaners or straws and relate this to modified phenotype ratios. (Use of scientific models to extend understanding.)
Possible assessments
- AS91153 Biology 2.1: Carry out a practical investigation in a biology context, with supervision (4 credits, internal)
- AS91154 Biology 2.2: Analyse the biological validity of information presented to the public (3 credits, internal)
- AS91157 Biology 2.5: Demonstrate understanding of genetic variation and change (4 credits, external)
- AS91159 Biology 2.7: Demonstrate understanding of gene expression (4 credits, external)
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Focus question 4: What impact do humans have on their surrounding ecosystem?
Students consider how:
- qualitative and/or quantitative data can be used to identify a distribution pattern in a community
- biotic and/or abiotic data relevant to the distribution pattern of a particular species can be used to explain the pattern, as can an organism’s biology
- species seldom live in isolation; the interrelationships between different organisms (including humans) affect the distribution of each.
Possible investigations
- Sample a stream above and below a dairy farm outfall or housing development. (Collecting quantitative data to identify relationships and patterns.)
- Compare the species distribution inside and outside a marine reserve. (Making comparisons and explaining using scientific ideas.)
- Evaluate the effectiveness of a pest control strategy by conducting 5-minute bird counts inside and outside a “mainland island” reserve. (Collecting quantitative data as evidence and using it to make a judgment.)
- Investigate successional changes on a landslide or cleared site by a longitudinal study, using photographic material.
- Is road kill data useful for estimating possum populations? (Evaluating the validity of data and of the conclusions drawn from them.)
- Observe successional changes in an un-mown lawn over a school year.
Possible assessments
- AS91153 Biology 2.1: Carry out a practical investigation in a biology context, with supervision (4 credits, internal)
- AS91154 Biology 2.2: Analyse the biological validity of information presented to the public (3 credits, internal)
- AS91158 Biology 2.6: Investigate a pattern in an ecological community, with supervision (4 credits, internal)
Last updated December 12, 2012
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