KS4 Tree of life

4.6 Inheritance, variation and evolution

4.6.1.4 DNA and the genome

• The genome of an organism is the entire genetic material of that organism

4.6.2.2 Evolution

• The theory of evolution by natural selection states that all species of living things have evolved from simple life forms that first developed more than three billion years ago
• If two populations of one species become so different in phenotype that they can no longer interbreed to produce fertile offspring they have formed two new species

4.6.3.4 Evidence for evolution

• Evidence for Darwin’s theory is now available as it has been shown that characteristics are passed on to offspring in genes. There is further evidence in the fossil record

4.6.3.5 Fossils

• We can learn from fossils how much or how little different organisms have changed as life developed on Earth
• Students should be able to extract and interpret information from charts, graphs and tables such as evolutionary trees

4.6.4 Classification of living organisms

• Traditionally living things have been classified into groups depending on their structure and characteristics in a system developed by Carl Linnaeus
• Linnaeus classified living things into kingdom, phylum, class, order, family, genus and species. Organisms are named by the binomial system of genus and species
• Students should be able to describe the impact of developments in biology on classification systems
• Evolutionary trees are a method used by scientists to show how they believe organisms are related. They use current classification data for living organisms and fossil data for extinct organisms

Working scientifically

• Understand how scientific methods and theories develop over time
• Appreciate the power and limitations of science and consider any ethical issues which may arise
• Explain everyday and technological applications of science; evaluate associated personal, social, economic and environmental implications; and make decisions based on the evaluation of evidence and arguments
• Recognise the importance of peer review of results and of communicating results to a range of audiences

Experimental skills and strategies

• Recognise when to apply a knowledge of sampling techniques to ensure any samples collected are representative
• Communicating the scientific rationale for investigations, methods used, findings and reasoned conclusions through paper-based and electronic reports and presentations using verbal, diagrammatic, graphical, numerical and symbolic forms

8.2.9 Required practical activity 9

• Measure the population size of a common species in a habitat

Topic 3 – Genetics

• Describe the genome as the entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein
• Explain how DNA can be extracted from fruit

Topic 4 – Natural selection and genetic modification

• Explain Darwin’s theory of evolution by natural selection
• Describe how genetic analysis has led to the suggestion of the three domains rather than the five kingdoms classification method

Topic 9 – Ecosystems and material cycles
Core practical 9.5

• Investigate the relationship between organisms and their environment using field-work techniques, including quadrats and belt transects

Working scientifically

• Understand how scientific methods and theories develop over time
• Appreciate the power and limitations of science and consider any ethical issues which may arise
• Explain everyday and technological applications of science; evaluate associated personal, social, economic and environmental implications; and make decisions based on the evaluation of evidence and arguments
• Recognise the importance of peer review of results and of communicating results to a range of audiences

Experimental skills and strategies

• Recognise when to apply a knowledge of sampling techniques to ensure any samples collected are representative
• Communicating the scientific rationale for investigations, methods used, findings and reasoned conclusions through paper-based and electronic reports and presentations using verbal, diagrammatic, graphical, numerical and symbolic forms

Topic B5: Genes, inheritance and selection
B5.1 Inheritance

• Describe the genome as the entire genetic material of an organism

B5.2 Natural selection and evolution

• Describe the impact of developments in biology on classification systems. To include: natural and artificial classification systems and use of molecular phylogenetics based on DNA sequencing
• Describe evolution as a change in the inherited characteristics of a population over time, through a process of natural selection, which may result in the formation of new species
• Describe the evidence for evolution. To include: fossils
• Describe the work of Darwin and Wallace in the development of the theory of evolution by natural selection and explain the impact of these ideas on modern biology

Working scientifically

• Understand how scientific methods and theories develop over time
• Appreciate the power and limitations of science and consider any ethical issues which may arise
• Explain everyday and technological applications of science; evaluate associated personal, social, economic and environmental implications; and make decisions based on the evaluation of evidence and arguments
• Recognise the importance of peer review of results and of communicating results to a range of audiences

Experimental skills and strategies

• Recognise when to apply a knowledge of sampling techniques to ensure any samples collected are representative
• Communicating the scientific rationale for investigations, methods used, findings and reasoned conclusions through paper-based and electronic reports and presentations using verbal, diagrammatic, graphical, numerical and symbolic forms

Chapter B1: You and your genes
B1.1 What is the genome and what does it do?

• All the genetic material of a cell is the organism’s genome

Chapter B3: Living together – food and ecosystems
B3.4 How are populations affected by conditions in an ecosystem?

• The distribution and abundance of organisms, and changing conditions, within an ecosystem can be investigated using techniques including: identification keys; transects and quadrats
• Investigate the distribution and abundance of organisms in an ecosystem

Chapter B6: Life on Earth – past, present and future
B6.1 How was the theory of evolution developed?

• The modern theory of evolution by natural selection combines ideas about genes, variation, advantage and competition to explain how the inherited characteristics of a population can change over a number of generations
• A new species can arise if the organisms in a population evolve to be so different from their ancestors that they could no longer mate with them to produce fertile offspring
• The theory of evolution by natural selection was developed to explain observations made by Darwin, Wallace and other scientists, including:
  • the production of new varieties of plants and animals by selective breeding
  • fossils with similarities and differences to living species
  • the different characteristics shown by isolated populations of the same species living in different ecosystems
• The theory of evolution by natural selection illustrates how scientists continue to test a proposed explanation by making new observations and collecting new evidence, and how if the explanation is able to explain these it can become widely accepted by the scientific community

B6.3 How does our understanding of biology help us classify the diversity of organisms on Earth?

• The enormous diversity of organisms on Earth can be classified into groups on the basis of observed similarities and differences in their physical characteristics and, more recently, their DNA. We are more likely to classify species into the same group if there are lots of similarities in their genomes (i.e. if they have many genes, and genetic variants, in common). Genome analysis can also suggest whether different groups have a common ancestor, and how recently speciation occurred
• Describe the impact of developments in biology on classification systems, including the use of DNA analysis to classify organisms

Chapter B7: Ideas about Science
IaS1 What needs to be considered when investigating a phenomenon scientifically?

• The aim of science is to develop good explanations for natural phenomena. There is no single ‘scientific method’ that leads to good explanations, but scientists do have characteristic ways of working. In particular, scientific explanations are based on a cycle of collecting and analysing data

IaS3 How are scientific explanations developed?

• Scientific explanations and theories do not ‘emerge’ automatically from data, and are separate from the data. Proposing an explanation involves creative thinking. Collecting sufficient data from which to develop an explanation often relies on technological developments that enable new observations to be made
• Findings reported by an individual scientist or group are carefully checked by the scientific community before being accepted as scientific knowledge

IaS4 How do science and technology impact society?

• Scientists must communicate their work to a range of audiences, including the public, other scientists, and politicians, in ways that can be understood. This enables decision-making based on information about risks, benefits, costs and ethical issues

Chapter B8: Practical skill

• Application of appropriate sampling techniques to investigate the distribution and abundance of organisms in an ecosystem via direct use in the field