book- chapter 1

• Human biological science is the scientific study of humans, both as individuals and as populations, and the study of the interaction between humans and their environment
• A lot is known and understood about humans, but much still remains to be discovered
• Science is a process of inquiry and a body of knowledge gained by systematic observation and testing of ideas
• Scientific knowledge is not fixed and unchanging, it continually increases as new discoveries are made
• Human biology is a body of knowledge relating to humans and is concerned with finding out more about the human species
• Knowledge gained in human biology is subject to change as research reveals more about the topics covered
• Human biologists must specialize in a particular field of study relating to humans, such as anatomy, physiology, nutrition or biochemistry
• Methods of investigating in human biological science:
• Literature review involves reviewing books, scientific journals, and the Internet to see what information has already been collected by others
• Observation involves gathering information using the senses or instruments that enhance the senses, such as a microscope or stethoscope
• Classification is placing things in groups based on the similarity of their characteristics
• Experimentation involves proposing a hypothesis, designing experiments to test it, and conducting controlled experiments to gather data
• Variables in an investigation:
• Independent variable: the factor being investigated and deliberately changed to determine its effects
• Dependent variable: the factor that changes due to changes in the independent variable
• Controlled variables: factors kept the same for both control and experimental groups in an experiment
• Developing a hypothesis:
• A hypothesis is a statement of the expected relationship between the independent and dependent variables that can be tested
• A good hypothesis is a definite statement, short, has a single idea that can be tested, and usually links the independent and dependent variables
• A hypothesis must be able to be tested and must state the relationship between the variables
• Testing the hypothesis:
• Testing involves using a suitable experiment to support or disprove the hypothesis, with only one variable tested at a time
• A control experiment is done with standard conditions to compare with the experimental group where the independent variable is changed
• Scientific experiments involve repetition, measurement, and direct observation to gather data
• Presentation of data:

  • Tables and graphs are effective tools to organise data
  • Tables are organised and concise ways of presenting data
  • Tables are particularly useful for presenting numerical data
  • Rules for drawing up a table to present experiment results:
  • Table must have an informative title stating variables investigated
  • Data presented in columns, with independent variable usually on left and dependent variable on right
  • Each column has a heading naming variable and units of measurement
• Graphs:

  • Graphs show how changes in one variable affect a second variable
  • Independent variable on horizontal axis, dependent variable on vertical axis
  • Include title summarising relationship between variables
  • Label axes with variable names and units of measurement
  • Use scale with equal intervals of units on each axis
• Line graphs:

  • Used for continuous data representation
  • Line of best fit drawn to show trend between variables
• Bar and column graphs:

  • Used for discrete data representation
  • Data represented by rectangles of equal width, with spaces between them
  • Length of each rectangle indicates quantity for easy comparison
• Histograms:

  • Used to show frequencies of particular values or characteristics
  • Columns represent frequency, with no space between them
  • Columns are of equal width, used when data grouped into categories
• Key concept:

  • Tables and graphs organise and display data to identify trends
• Accuracy: The extent to which the measurements are correct
• Bar graph: A graph for discrete data using horizontal bars
• Blind experiment: An experiment where the subjects do not know whether they are receiving the test treatment or the placebo
• Classification: The grouping of organisms based on the similarity of their characteristics; the placement of organisms into groups
• Column graph: A graph for discrete data using vertical bars
• Conclusion: A summary of how the data supports or disproves the hypothesis
• Continuous data: Quantitative data with an infinite number of possibilities
• Control: A procedure carried out to give a comparison in an experiment
• Controlled variable: A factor kept the same for both the control and the experimental groups in an experiment
• Data: Observations and measurements; the results of an experiment