WJEC Biology for A2: 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. Working Scientifically is further discussed in more detail below. Working Scientifically The value of science lies in its consistency. Given suitable conditions, plants photosynthesise; ingesting certain bacteria produces particular predictable symptoms; burning more fossil fuel puts more carbon dioxide into the atmosphere. Such observations always hold, which is why scientific knowledge is so valuable. It is not a matter of opinion and it is demonstrably true, within the limits of experiment. However, as methodology and technology improve, understanding improves, so concepts and explanations are modified. Science is, thus, updated in a continuing process. The scientific community has procedures for testing and checking the findings and conclusions of individual scientists. The serious way that scientific fraud is treated builds confidence in the procedures. It is important that you are able to demonstrate your understanding of the scientific process and the impact that scientific knowledge has on individuals and on society. These are demonstrated throughout this course and are highlighted throughout this book. Examples are given below: ▪ Data from observations and measurements are of critical importance, e.g. 3.5(m) The effects of human activities on the carbon cycle, including the change in species distribution and extinction as a result of climate change. ▪ A good explanation allows a prediction of what may happen in other situations, e.g. 3.5(a) An explanation of energy flow and nutrient cycling through ecosystems and how this leads to changes in population size and composition. ▪ There may be a correlation, a cause or a chance link between a factor and an outcome, e.g. 4.3(d) The use of a chi squared test to test for Mendelian inheritance. ▪ A new theory may provide an explanation for the available data, e.g. 3.1(a) The synthesis of ATP involving a flow of protons down a proton gradient through ATP synthetase, in chemiosmosis. The converse is also true, i.e. new data may support a theory or require its amendment. ▪ Devising and testing a scientific explanation is not a simple and straightforward process. There is always uncertainty in data. An observation may be untrustworthy because of the limitations of either the measuring equipment or the person using it, e.g. 4.4(i) The use of stem cells for replacing damaged tissues and organs. ▪ Devising an experiment and deducing an explanation for the results are creative steps. There are different ways to demonstrate the same effect and different people may provide different explanations for the same data, e.g. 3.2(k) The role of leaf structure in allowing plants to photosynthesise efficiently: the diameter and distribution of stomata in leaves of a given species may differ in different habitats. There are likely to be conflicting pressures determining their values. ▪ The application of scientific knowledge in new technologies, materials and devices greatly enhances our lives, but may have unintended and undesirable side effects, e.g. 4.5(d) The knowledge derived from the inventions of the polymerase chain reaction and genetic fingerprinting have significant forensic use, but skill is required for the proper interpretation of gene profiles. ▪ The application of science has social, economic, political and ethical implications, e.g. 3.6(f) The concept of planetary boundaries shows how human behaviour has an impact on all life on Earth through its effects on planet-wide systems. 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, on p70 of your specification. With the exception of statistics, which is equivalent to Level 3 or A Level, the level of understanding is equivalent to Level 2 or GCSE Mathematics. working scientifically Introduction 5