SvS Biology 2001 - module 9.3: Blueprint of Life

According to the Board of Studies Syllabus, the purpose and function for studying this unit is summarised by the following statements:
(ref: NSW Board of Studies Stage 6 Syllabus, page 47)

Contextual Outline

Because all living things have a finite life span, the survival of each species depends on the ability of individual organisms to reproduce. Reproduction takes many forms, grouped as either sexual or asexual, and the mode of reproduction determines the variation from one generation to the next. The continuity of life is assured when the chemical information that defines it is passed on from one generation to the next on the chromosomes. It is the sequence of nucleotides that carries the information that determines the characteristics of an organism.

Current research continues to increase our knowledge of the genetic code and also increase our understanding of how cells read and implement the coded information. Modern molecular biology is also providing opportunities to alter the information transferred from one generation to the next in technologies such as cloning and in the production of transgenic species.

The segregation and independent assortment of the genetic information within a species provides the variation necessary to produce some individuals with characteristics that better suit them to surviving and reproducing in their environment. Changes in the environment may act on these variations. The identification of mutations and their causes becomes important in preventing mutations and in identifying and potentially nullifying the effects of mutations in living organisms.

1. Evidence of evolution suggests that the mechanisms of inheritance, accompanied by selection, allow change over many generations

• outline the impact on the evolution of plants and animals of:
– changes in physical conditions in the environment
– changes in chemical conditions in the environment
– competition for resources
• describe, using specific examples, how the theory of evolution is supported by the following areas of study:
– palaeontology, including transitional forms
– biogeography
– comparative embryology
– comparative anatomy
– biochemistry
• explain how Darwin/Wallace’s theory of evolution by natural selection and isolation accounts for adaptive radiation leading to divergent evolution and convergent evolution

• plan, choose equipment or resources and perform a first-hand investigation to model natural selection
• identify data sources, gather, process, analyse and present evidence from secondary sources and use available evidence to prepare a case study using an Australian example to show how changes in physical and chemical conditions, or increased competition for resources, have led to changes in a species
• process and analyse information from secondary sources to trace the fossil record of one group of organisms
• perform a first-hand investigation or gather information from secondary sources (including photographs/ diagrams/models) to observe, analyse and compare the structure of a range of vertebrate forelimbs
• gather and process information from secondary sources to describe and use available evidence to analyse, using a named example, how advances in technology have changed scientific thinking about evolutionary relationships
• identify data sources, gather, analyse and present information from secondary sources on the historical development of theories of evolution and use available evidence to assess social and political influences on these developments

2. Gregor Mendel’s experiments helped advance our knowledge of the inheritance of characteristics

• outline the experiments carried out by Gregor Mendel
• describe the aspects of the experimental techniques used by Mendel that led to his success
• describe outcomes of monohybrid crosses involving simple dominance using Mendel’s explanations
• distinguish between homozygous and heterozygous genotypes in monohybrid crosses
• distinguishes between the terms allele and gene, using examples
• explain the relationship between dominant and recessive genes and phenotype using examples
• outline the reasons why the importance of Mendel’s work was not recognised until some time after it was published

• perform an investigation to construct pedigrees or family trees, trace the inheritance of selected characteristics and discuss their current use
• process information from secondary sources to analyse and solve problems involving monohybrid crosses using Punnet squares or other appropriate techniques
• process information from secondary sources to identify and describe examples of hybridisation in horticulture or agriculture and explain its advantages/disadvantages

• outline the roles of Sutton and Boveri in identifying the importance of chromosomes
• describe the chemical nature of chromosomes and genes
• explain the relationship between the structure and behaviour of chromosomes during meiosis and the inheritance of genes
• explain the role of gamete formation and sexual reproduction in variability of offspring
• describe the inheritance of sex-linked genes, and genes that exhibit co-dominance and explain why these do not produce simple Mendelian ratios
• describe the work of Morgan that led to the identification of sex linkage
• explain the relationship between homozygous and heterozygous genotypes and the resulting phenotypes in examples of codominance
• outline ways in which the environment may affect the expression of a gene in an individual

• perform a first-hand investigation or process and present information from secondary sources to model the process of meiosis to demonstrate crossing over, segregation of chromosomes and the production of haploid gametes
• process information from secondary sources to analyse and solve problems involving co-dominance and sex linkage
• identify data sources and perform a first-hand investigation or process and present information from secondary sources to investigate the effect of the environment on phenotype

4. The structure of DNA can be changed and such changes may be reflected in the phenotype of the affected organism

• outline the role of DNA in the transmission of genes from one generation to the next
• describe the process of DNA replication and explain its significance
• outline, using a simple model, the process by which DNA controls the production of proteins and/or polypeptides
• identify mutations as a source of new alleles in organisms
• describe mutations as changes in the DNA information on a chromosome
• outline, using a simple model, how changes in DNA sequences can result in changes in proteins produced and thus changes in cell activity
• identify that environmental factors may increase the rate of mutation using examples of mutagens
• explain how an understanding of the source of variation in organisms has provided support for Darwin’s theory of evolution by natural selection
• describe the concept of punctuated equilibrium in evolution and how it differs from the gradual process proposed by Darwin

• perform a first-hand investigation or process information from secondary sources to develop a simple model for protein synthesis
• identify data sources, gather, process and analyse information from secondary sources to outline the evidence that led to Beadle and Tatum’s ‘one gene – one protein’ hypothesis and to explain why this was altered to the ‘one gene – one polypeptide’ hypothesis
• process and analyse information from secondary sources to illustrate, by using examples, how mounting evidence for the mutagenic nature of radiation and certain chemicals was collected during the twentieth century
• process and analyse information from secondary sources to explain how the development of antibiotic resistance in bacteria or insecticide resistance in insect pests are modern examples of ‘natural’ selection
• process information from secondary sources to describe and analyse the relative importance of the work of:
– James Watson
– Francis Crick
– Rosalind Franklin
– Maurice Wilkins
in determining the structure of DNA and in exemplifying the role of collaboration and effective communication in scientific research

5. Current reproductive technologies and genetic engineering have the potential to alter the path of evolution

• identify how the following current reproductive techniques may alter the genetic composition of a population:
– artificial insemination
– artificial pollination
– cloning
• outline the processes used to produce transgenic species and include examples of this process and reasons for its use
• discuss the potential impact of the use of reproduction technologies and genetic engineering on genetic diversity of species using a named plant and animal example that have been genetically altered
• explain the need to maintain biodiversity and identify and discuss a current effort to monitor biodiversity

• process and analyse information from secondary sources to research a methodology used in cloning organisms
• process, analyse and present information from secondary sources to identify examples of the use of transgenic species and use available evidence to debate the ethical issues arising from the development and use of transgenic species

H1 evaluates how major advances in scientific understanding and technology have changed the direction or nature of scientific thinking

H4 assesses the impacts of applications of biology on society and the environment

H6 explains why the biochemical processes that occur in cells are related to macroscopic changes in the organism

H8 evaluates the impact of human activity on the interactions of organisms and their environment

H10 describes the mechanisms of evolution and assesses the impact of human activity on evolution

H12 evaluates ways in which accuracy and reliability could be improved in investigations

H13 uses terminology and reporting styles appropriately and successfully to communicate information and understanding

H16 justifies positive values about and attitudes towards both the living and non-living components of the environment, ethical behaviour and a desire for a critical evaluation of the consequences of the applications of science.