The Science of Biology

The Science of Biology

What is Science? • Science is: • always changing. • a “way of knowing” about the world around you. • a process, not a thing. • Science also refers to the knowledge that scientific studies have gathered over the years.

What is Science? • Science: • deals only with the natural world. • Is a way to collect and organize information in an orderly way. • Is based on evidence not beliefs.

Goals of Science • Scientists: • provide natural explanations for events in the natural world. • aim to use those explanations to understand patterns in nature and to make useful predictions about natural events.

Science in Context – Where Ideas Come From • Scientific Attitudes can inspire the observations & questions that lead to experiments! • Curiosity – Researchers want to know why or how things happen. • Skepticism – Good scientists question existing ideas and refuse to accept explanations without evidence. • Open-Mindedness – Scientists must be willing to different ideas, even if it doesn’t agree with their hypotheses. • Creativity – Researchers must think creatively to develop experiments.

Science in Context – Where Ideas Come From • Practical Problems can lead to scientific investigations • Example: Salt marshes are vital ecosystems that are under pressure from housing development • This leads to questions such as: • Should marshes be protected from housing development? • If houses are located near salt marshes, can they be designed so the marshes are protected?

Science in Context – Where Ideas Come From • Technology is closely linked to scientific discoveries. • A discovery in one area of science may lead to a new technology • This new technology may then allow scientists in another field to ask questions that will lead to new investigations.

Communicating Results • Peer Review involves having scientific papers reviewed by anonymous experts. • These papers can then be published in scientific journals • This allows researchers to share ideas and to test and evaluate each other’s work • Reviewers look for errors, fraud, and mistakes in techniques

Communicating Results • Sharing Knowledge and New Ideas • Once research has been published, it can lead to many new ideas and processes.

Scientific Theories • When evidence from many studies supports several related hypotheses, researchers may propose a theory that ties the hypotheses together. • In science, the word theory has a very different meaning than it does in everyday life! • A scientific theory is a well-tested explanation that unifies a broad range of observations and hypotheses. • A scientific theory enables scientists to make accurate predictions about new situations. • A scientific theory may become the dominant view among scientists, but is not considered absolute truth!

Science and Society • Science and Society go hand in hand. • Using science involves understanding its context in society and its limitations. • It is important for you to be educated about science and biology so that you can take on an active role in society…think about it! • Stem-cell research • HGH hormones • Blood doping • Vaccines

Science and Society – Science, Ethics and Morality • Scientists can explain “why” something happens using natural phenomena. • Pure science does not include ethical or moral viewpoints!

Science and Society – Avoiding Bias • The way science is applied in society can be affected by bias. • Science aims to be objective, but scientists are human! • Data can be misinterpreted or misapplied by scientists who want to prove a particular point. • By understanding science, the public can help to make sure that bias does not affect the application of science in a way that benefits humanity.

Science and Society – Understanding and Using Science • Understanding science is not about memorizing and believing a series of facts. • It is important for you to be understand the process of science and how scientists developed the ideas you are learning about.

Science enables us to take actions that affect events in the world around us. • To make certain that scientific knowledge is used for the benefit of society, all of us must understand the nature of science----its strengths, its limitations, and its interactions with our culture.

Scientific Methodology • We use scientific processes every day to solve problems! • There is not just one specific way to address scientific research. • The general style of investigation used by scientists is called “scientific methodology”.

Scientific Methodology • Step 1: Observations and Questions • Observation is the act of noticing and describing events or processes in an orderly way. • Curiosity, skepticism, open-mindedness, and creativity are all characteristics that scientists need to make observations and ask thought-provoking questions. “Think something that nobody has thought yet, while looking at something that everybody sees” –Arthur Schopenhauer

Let’s try it! • A woman leaves home and makes three left turns. She returns home again. On the way, she passed two women with masks. Who were the two women?

Answer: The umpire and the catcher. • False Assumption: That the woman was walking on city streets. She really is on a baseball field

Observations • You notice that there is a decline in the frog population in a local pond.

Step 2: Inferring and Forming a Hypothesis • An inference is a logical interpretation based on what scientists already know. • Inferences can lead to a hypothesis, which is a scientific explanation for a set of observations that can be tested.

Forming a Hypothesis • Inferring that pollution from several new factories in the area may be a factor in the declining frog population. • Suggesting (forming a hypothesis) that acid rain could be causing a decline in the frog population.

Step 3: Designing Controlled Experiments • Testing a hypothesis involves designing experiments that keep track of factors that can change, or variables. • Variables can include: temperature, light, time, and availability of nutrients. • If possible, only one variable should be changed. This is called a controlled experiment.

Controlling Variables • Independent Variable: • The variable that is deliberately changed. • This variable is also called the manipulated variable. • Dependent Variable: • The variable that is observed and that changes in response to the independent variable. • Also called the responding variable.

Controlling Variables • It is important to control variables so researchers can tell which variable is responsible for any results they observe. • All experiments should have both an experimental group and a control group. • Control group is exposed to the same conditions as experimental group except one independent variable.

Francesco Redi OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Independent Variable gauze covering that keeps flies away from meat Dependent Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Designing an Experiment • Take water samples at various times of the year to determine acidity. • Measure amount of precipitation during each time interval.

Designing an Experiment • Independent (manipulated) variable – amount of precipitation during the time interval • Dependent (responding) variable – pH (measure of acidity) of water sample. • Controlled factors – location where sample is taken, amount of water used for sample, tool used for measuring pH, length of time intervals between measurements.

Step 4: Collecting and Analyzing Data • Scientists make detailed records of experimental observations, gathering information called data. • Two main types of data: • Quantitative: numbers obtained by counting or measuring. • Qualitative: descriptive, involves characteristics that cannot be counted or measured.

Quantitative or Qualitative?? • A: Quantitative B: Qualitative ___1. Number of frogs/square foot of pond ___2. Noting that frogs have a darker underbelly. ___3. Observing that the grass is not growing in some areas. ___4. The acidity of levels after rainfall.

Quantitative or Qualitative?? • A: Quantitative B: Qualitative _A_1. Number of frogs/square foot of pond _B _2. Noting that frogs have a darker underbelly. _B _3. Observing that the grass is not growing in some areas. _A_4. The acidity of levels after rainfall.

Analyze Data • From the water samples, determine the amounts of acid in the pond at various times of the year. • Compare the change in pH to the amount of rainfall during that interval.

Step 4: Collecting & Analyzing Data • Research tools – appropriate tools must be used to collect and analyze data. • May range from simple devices (ex. metersticks, beakers) to complex equipment (ex. Computer-controlled measuring equipment) • Can also include charts, graphs, journals, sketches, etc.

Step 4: Collecting & Analyzing Data • Sources of Error – Researchers are careful to avoid error in data collection and analysis. • Measuring tools, such as scales and graduated cylinders have limited accuracy • Sample sizes should be carefully chosen; often sample groups must be quite large. • The larger the sample size, the more reliable the results!

Step 5: Drawing Conclusions • Data is used to support, refute, or revise the hypothesis that is being tested. • Many experiments may be needed to support one hypothesis. • Peer review and sharing knowledge

Drawing Conclusions • Increased acid rain during spring months will cause a decrease in frog population. • May lead to a new hypothesis – The decreased frog population is due to acid rain inhibiting egg development. • Researchers will then design an experiment to test the new hypothesis!

Drawing Conclusions Remember, science is always changing! Observations lead to hypotheses, which lead to experiments, which lead to new observations!

When Experiments Are Not Possible • It’s not always possible to test a hypothesis with an experiment. • Sometimes, researchers develop hypotheses that can be tested by observations. • Example – Animal behavior researchers might want to learn how animal groups interact in the wild by making field observations that disturb the animals as little as possible. • Researchers analyze data from these observations and devise hypotheses that can be tested in different ways.

When Experiments Are Not Possible • Ethics can prevent certain types of experiments—especially on human subjects. • Example, medical researchers may suspect that a chemical causes cancer • They would use volunteers who have already been exposed to the chemical and compare them to people who have not been exposed to the chemical. • Researchers still try to control as many variables as possible, and might exclude volunteers who have serious health problems or known genetic conditions. • Medical researchers always try to study large groups of subjects so that individual genetic differences do not produce misleading results.

Science- The basics • In order to communicate with each other, scientists have to understand what each one of us is saying. • SI Base Units- agreed upon terms that allow a common ground to measure things. All based on the metric system. • Mass- gram • Volume- liter • Length- meter • We can always convert these by adding prefixes centi- milli- kilo- etc.

Biology…the study of LIFE! • Characteristics of living things • Made up of cells • Based on a universal genetic code • Obtain and use materials and energy • Grow and develop • Reproduce • Respond to their environment • Maintain a stable internal environment • Change over time

Cells • Cells are the smallest functional unit of life. • Cells are complex and highly organized. • Organisms are composed of one or more cells.

Universal Genetic Code • All organisms store the complex information they need to live, grow, and reproduce in a genetic code. • The molecule is called DNA (deoxyribonucleic acid). • This information is copied and passed down each generation.

Obtain and Use Materials and Energy • All living things take in materials and energy to grow, develop and reproduce. • Metabolism includes all the chemical reactions used to break down these materials.

Grow and Develop • Every organism has a pattern of growth and development. • A single fertilized egg divides over and over. • As these cells divide, they differentiate….which means they look different from one another and take on different jobs.

Reproduce • All organisms reproduce! • Two types of reproduction: • Asexual reproduction-One organism produces offspring identical to itself. • Sexual reproduction-cells from 2 parents unite to form the first cell of an organism

Respond to their Environment • Organisms detect and respond to stimuli in their environment. • Example: Some plants can produce unsavory chemicals to ward off caterpillars that feed on their leaves. Bombardier Beetle (releases a high pressure boiling spray)

Maintain a Stable Internal Environment • All organisms must maintain a stable internal environment, even when the external environment changes dramatically….this is called homeostasis. • Examples: • Controlling body temperature (sweating/shivering) • Guard cells in plants

Change Over Time • Over many generations, groups of organisms evolve…change! • Evidences for this change can be found in living organisms, fossils, proteins, and DNA.

Big Ideas in Biology 1. Cellular basis of life – living things are made of cells 2. Information and Heredity– Life is based in a universal genetic code 3. Matter and Energy – Living things obtain and use materials and energy

The Science of Biology