Section 1.1: What is Science? Section 1.2: Science in Context Section 1.3: Studying Life

Transcription

1 Section 1.1: What is Science? Section 1.2: Science in Context Section 1.3: Studying Life

2 1.1 What science is and is not Science is an organized way of gathering and analyzing evidence about the natural world. Science is different from other human endeavors because it only deals with the natural world, scientists collect and organize data looking for patterns and connections, and scientists propose explanations based on evidence. From a scientific perspective, all objects in the universe are governed by universal natural laws whether the objects are large or small.

3 Goals of Science One goal of science is to provide natural explanations for events in the natural world. These explanations help us with predictions about natural events.

4 Science, Change, and Uncertainty Almost every scientific discovery raises more questions than it answers. Science rarely proves anything in absolute terms. Uncertainty is part of the scientific process. Why do you think there is uncertainty in science?

5 Scientific methodology: The heart of science Two main approaches to learning about nature Discovery Science = gather data by verifiable observations & measurements Ex. Baby bats cling to their mother in flight. Ex. Sequence of DNA (an observation) Hypothesis-Driven Science = conclusions drawn from observations taken during discovery science lead to more questions. Ex. Why do baby bats cling to their mother in flight? Ex. What is the function of the DNA sequence?

6 Scientific methodology: The heart of science Scientists use a general style of investigation called Scientific Method(ology). The Scientific Method = steps followed to pose and test hypotheses. Involves observing and asking questions, making inferences and forming hypothesis, conducting controlled experiments, collecting and analyzing data, and drawing conclusions.

7 Forming Hypotheses (Practice): Observation: Concentrations of Carbon Monoxide in the air increase between 8-10 a.m. and again between 4-6 p.m. Knowledge/Inference: Cars emit Carbon Monoxide. The carbon in these emissions combines with oxygen in the air to create carbon dioxide. Hypothesis: Carbon Dioxide increases with the increase in traffic patterns during a normal work day. blog.arendsen.net

8 Observing and asking questions Scientific investigations begin with observation, the act of noticing and describing events or processes in a careful, orderly way. What can you observe from this image?

9 Inferring and forming a hypothesis An inference is a logical interpretation based on what scientists already know What can you infer from the previous image? Inferences usually lead to a hypothesis. A hypothesis is a scientific explanation for a set of observations that can be tested in ways that support or reject it. What are some examples of a hypothesis you can formulate from your inference?

10 Designing controlled experiments Testing a scientific hypothesis often involves designing an experiment that keeps track of various factors that can change, these factors are variables. Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed. All other variables should be kept unchanged or controlled. This type of experiment is called a controlled experiment. Why would we do this?

11 Controlling variables What is a variable? The variable that is deliberately changed is the independent variable (manipulated) The variable that is observed and that changes in response to the independent variable is called the dependent variable (responding).

12 Control and experimental groups An experiment is normally divided into control and experimental groups. A control group is exposed to the same conditions and receives no changes. In the experimental group, one variable is changed (independent variable).

13 Collecting and analyzing data Scientists make detailed records of experimental observations, gathering information called data. Two main types of data: Quantitative data are numbers obtained by counting or measuring (Quantity) Length, height, area, volume, weight, speed, time, temperature, humidity, sound levels, cost, members, ages, etc. Qualitative data are descriptive and involve characteristics that cannot usually be counted (Quality) Colors, textures, smells, tastes, appearance, beauty, etc.

14 Scientists report their findings: publish it in scientific magazines/journals report it to other scientists provide findings to the scientific community for scrutiny Common Ways to Present Information: Chart/Table = summarizes data Diagram/Model = explains or shows detail Bar Graph = shows magnitude of data Line Graph = relates two sets of data; shows how data changes Circle Graph = relates parts of a whole Flowchart = shows the order of steps Scatter Plot = shows relationship between sets of data

15 Interpreting Graphs Independent variable = x axis; Dependent variable = y axis % transmission is used to determine algal growth

16 Sources of Error Researches/ Scientist are human Must be carful when collecting data Tools have limited accuracy, natural variation Sample size and the way data is analyzed is important What do you think is more reliable a small sample or a large sample?

17 Research tools Research tools involve metersticks, calculators, microscopes, computers, graphs, journals, ect Sometimes it involves everyday common items; zip ties, pvc, rope, etc

18 Drawing Conclusions Scientists use experimental data as evidence to support, refute, or revise the hypothesis being tested, and to draw a valid conclusion. A conclusion is an idea or decision reached upon completion of research Hypothesis are often not fully supported or refuted by one set of experiments. In that case, the original hypothesis is reevaluated and revised; new predictions are made, and new experiments are designed.

19 When experiments are not possible It is not always possible to test a hypothesis with an experiment. Observations can replace controlled experiments. Observing things in their natural state Ethics sometime prevents experiments from being performed, ex: Medicine.

20 Left side assignment Turtles Ahoy

21 1.2 Science in context Scientific methodology is closely linked to exploration and discovery. Good scientists share scientific attitudes, or habits of mind, that lead them to exploration and discovery. Curiosity, skepticism, open-mindedness, and creativity help scientists generate new ideas. What are some examples of curiosity, openmindedness, creativity, and skepticism?

22 Practical problems Sometimes, ideas for scientific investigations arise from practical problems. Example: Will removing salt marshes from the environment for housing projects affect the ecosystem a great deal?

23 The role of technology Technology, science, and society are closely linked. Discoveries in one field of science may lead to new technologies. Those technologies in turn, enable scientists in other fields to ask new questions or to gather data in new ways.

24 Communicating results: reviewing and sharing ideas Scientists focus on one subject intensely for months, even years before they decide to communicate their experiments and observations to the scientific community. Peer review is when scientific work is reviewed by anonymous, independent experts. Once research has been published it enters the dynamic market place of scientific ideas.

25 Scientific theories What is a theory? A scientific theory describes a well-tested explanation for a range of phenomena. It enables scientists to make accurate predictions about new situations. Scientific theories are different from laws and theories DO NOT become laws. A useful theory that has been thoroughly tested and supported by many lines of evidence may become a dominant view among scientists but no theory is considered absolute truth. What are some differences between theories and laws?

26 What s the difference between theories and laws? Law describes what nature does under certain conditions, and will predict what will happen as long as those conditions are met. A theory explains how nature works. Others delineate law and theory based on mathematics -- Laws are often times mathematically defined (once again, a description of how nature behaves) whereas theories are often non-mathematical. Looking at things this was helps to explain, in part, why physics and chemistry have lots of "laws" whereas biology has few laws (and more theories). In biology, it is very difficult to describe all the complexities of life with "simple" (relatively speaking!) mathematical terms.

27 Science and society Scientific research does not only include science itself, but also involve the society in which we live. Using science involves understanding its context in society and its limitations. What would be some of our limitations when it comes to research?

28 Science, ethics, and morality When scientists explain why something happens, their explanation involves only natural phenomena. No ethical or moral view Ex: STEM Cell therapy Avoiding bias; a bias is a particular preference or point of view that is personal, rather than scientific. Science will keep changing as long as humans keep wondering. Understanding biology will help you realize that we humans can predict the consequences of our actions and take an active role in directing our future and that of our planet.

29 1.3 Studying life What are some characteristics of living things? Biology is the study of life. No single characteristic is enough to describe a living thing. We can list characteristics that most living things have in common. Living things are made up of basic units called cells, are based on a universal genetic code, obtain and use materials and energy, grow and develop, reproduce, respond to their environment, and change over time.

30 Characteristics of living things Living things are based on a universal genetic code. All organisms store the complex information they need to live, grow, and reproduce in a genetic code written in a molecule called DNA. This information is passed on from parent to offspring.

31 Characteristics of Living things Living things grow and develop

32 Characteristics of living things Living things respond to their environment. A stimulus is a signal to which an organism responds.

33 Characteristics of living things Living things are made up of cells. Organisms are composed of one or more cells.

34 Characteristics of living things Living things reproduce, meaning that they produce new, similar organisms. There are two types of reproduction: Sexual reproduction: When cells from two parents unite to form the first cell of a new organism. Asexual reproduction: When a single organism produces offspring identical to itself.

35 Characteristics of living things Asexual Reproduction Sexual Reproduction

36 Characteristics of living things Living things maintain a stable internal environment. All organisms need to keep their internal environment relatively stable, even when external conditions change dramatically; this is known as homeostasis.

37 Characteristics of living things Living things obtain and use material and energy. The combination of chemical reactions (building and breaking down material) is metabolism.

38 Characteristics of living things Taken as a group, living things evolve. What does it mean to evolve? Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago.

39 Evolution through Natural Selection

40 Left side assignment Characteristics of living things worksheet

41 Big ideas in Biology The study of biology revolves around several interlocking big ideas: Cellular basis of life Information and heredity Matter and energy Growth, development, and reproduction Homeostasis Evolution Structure and Function Unity and diversity of life Interdependence in nature Science as a way of knowing

42 Big ideas in biology All forms of life are connected into a biosphere which means living planet. What s the name of our biosphere?

43 Fields of Biology Biology includes many overlapping fields that use different tools to study life from the level of molecules to the entire planet. Botany Ecology Microbiology Zoology Biotechnology Marine biology Forensics Phylogenetics Evolutionary biology Molecular biology Genetics Epidemiology Darwinian medicine

44 Performing Biological Investigations Scientific measurment Rely on a common system of measurement Replicate work and gather quantitative data Most scientists use the metric system when collecting data and performing experiments. SI Units (International system), based on multiples of 10 Length = meter (m) Volume = liter (l) Mass (weight) = Kilogram (kg) Temperature = Celsius ( C) 0= freezing, 100 boiling

45 Left side assignment Scientific measurement

46 Performing Biological Investigations Safety Safe procedures/safe practice Lab safety and hazardous waste training Scientists working in a laboratory or in the field are trained to use safety procedures when carrying out investigations, use Careful preparation is the key to staying safe during scientific activities. The single most important safety rule is to always listen and follow instructions Safety and validity of work