WJEC Biology for AS: Student Bk

YOU SHOULD KNOW › › › Learning objectives are provided. They are more specific to the area being studied than the more general learning objectives listed at the start of the topic. This feature helps you to understand something about science itself, how scientific knowledge has been obtained, how reliable it therefore is and what its limitations are. It may also help you to have a deeper awareness of how science is used to improve our quality of life. It is important to understand the scientific process, to know how evidence has been gathered and how to evaluate it. These features will help you to develop the habit of approaching evidence with a questioning mind. How Science Works is further discussed in more detail below. How Science Works When science is encountered in everyday life, it is interesting because it helps us to understand something of the behaviour of the natural world. But it is increasingly important to understand the scientific process; how knowledge has been obtained, how reliable and accurate it is and what its limitations are. It is also important to appreciate the impact that scientific knowledge has on society as a whole and to distinguish it from the pseudo-science that permeates our culture. In other words, you need to question what is going on in the science that has an impact on your life. ▪ ▪ In order to do this you should appreciate the following: ▪ ▪ Evidence, that is data from observations and measurements, is of central importance. ▪ ▪ A good explanation may allow us to predict what will happen in other situations, enabling us to test our understanding. ▪ ▪ There may be a correlation between a factor and an outcome, which is not the same as a cause. ▪ ▪ Devising and testing a scientific explanation is not a simple and straightforward process. We can never ▪ ▪ be completely sure of the data. An observation may be inaccurate or unreliable because of the limitations of the design of the experiment, the measuring equipment or the person using it. ▪ ▪ Generating an explanation of results is a creative step. It is quite possible for different people to present different explanations for the same data. ▪ ▪ The scientific community has established procedures for testing and checking the findings and conclusions of individual scientists and arriving at an agreed view. Scientists report their findings at conferences and in special publications. ▪ ▪ The application of scientific knowledge in new technologies, materials and devices, greatly enhances our lives but may have unintended and undesirable side effects. ▪ ▪ The application of science may have social, economic and political implications and also ethical ones. ‘How Science Works’ is developed in this book through relevant topics, helping you to develop the relevant skills necessary to understand how scientists work and evaluate their findings. This will allow you to have a deeper awareness of how science is may be used to improve our quality of life. Some examples are given here, but a full list can be found in Appendix D following the course content in your specification: ▪ ▪ Data from observations and measurements are of central importance: Testing for reducing sugar (p17). ▪ ▪ An observation may be incorrect because of the limitations of either the measuring equipment or the person using it: Observations from light and electron microscopy (p44). ▪ ▪ Use theories, models and ideas to develop scientific explanations: Models of enzyme action (pp71–72). ▪ ▪ Proposing a theory may account for the data: The structure of DNA as proposed by Watson and Crick (p92). ▪ ▪ The use of the ultracentrifuge in understanding DNA replication (p96). ▪ ▪ Consider ethical issues in the treatment of humans, other organisms and the environment: Ethical considerations of tissue sampling (p112). ▪ ▪ The need to use a variety of evidence from different sources in making valid scientific conclusions: Assessing the degree of relatedness between organisms (pp141–142). ▪ ▪ Devising and testing a scientific explanation is not a simple and straightforward process: Using evidence from the use of 14 CO 2 in understanding translocation, as the mass flow theory did not explain certain features of the process (pp2124–215). Mathematical requirements As assessment of your mathematical skills is very important, some common uses of mathematics in biology are included throughout this book. There is nothing difficult here. You are preparing for a biology examination, not a mathematics exam, but it is still important to apply numerical analysis, and these examples will help you to do so. Mathematical requirements are given in Appendix C, at the end of the course content in the specification. The level of understanding is equivalent to Level 2, or GCSE Mathematics, other than the statistics required in the second year of the course, which is equivalent to Level 3 or A Level. How Science Works Introduction 5