2. Honors Biology The Science of Life Chapter 1 September 2011

3. Thinking about the Nature of Science What is science? What is biology? What makes science powerful? What characteristics must something have in order for it to be science? How does one “do” science?

4. Chapter 1-1: The Study of Biology Science as a Process Honors Biology September 2011

5. The World of Biology Biology: the study of life –Organized and scientific framework for answering questions about living things How do living things work? How do they interact with their environment? How do they change over time? What are the different types of living things?

6. What is Science? Science is an organized, evidence-based method of learning about the natural world. Skills Used By Scientists: –Observation skills – scientists use their senses (sight, hearing, touch, smell, and sometimes taste) to observe nature –Hypothesizing skills – scientists attempt to explain the observations by forming hypotheses or ideas –Analyzing and Interpreting skills – scientists analyze and interpret data collected during experiments while using prior knowledge and experience

7. How Scientists Work Using the Scientific Process –“Scientific Method” - No “one size fits all” process, different studies call for different methodologies –A generalized form: State the Problem/Ask a Question Form a Hypothesis & Make a Prediction Test Hypothesis with a Controlled Experiment Record and Analyze Data or Results Draw a Conclusion Based on Analysis Publish and Repeat Investigations

9. Ask a Question Scientists form questions when they observe nature through their senses (sight, hearing, touch, smell) Examples: –Some peaches are juicy and sweet. Others are spongy with very little flavor. What makes some peaches juicier than others? –My neighbor has thick, green grass. Mine is brown in spots and is thin. What does grass need to be healthy?

10. Ask a Question Practice Make an observation and form a scientific question about the pictures below.

11. Writing Hypotheses & Predictions Hypothesis – a proposed explanation for a set of observations or possible answer to a question –Must be testable, or it’s not scientific –Write the hypothesis as a clear statement, do not say “I think that ….” Prediction – a statement of what you expect to observe –Can be written as an “If the hypothesis is correct, then…” statement. ATTENTION - It is okay for your hypothesis and prediction to be wrong! Never change your hypothesis after an experiment to make it correct.

12. Hypothesis & Prediction Practice Write a possible hypothesis and prediction for each of the following observations. 1.The plants in Mr. Smith’s living room are large, healthy and green but the plants in Mr. Smith’s dining room are small and yellowish in color. 2.All of the fish in the classroom fish tank are healthy except for the algae eaters that keep dying. 3.There are only a few un-popped kernels in the popcorn that has been stored in the kitchen but a lot of kernels left in the popcorn that has been stored in the basement.

13. Testing the Hypothesis: Designing Controlled Experiments * Whenever possible, an experiment should be designed to have only ONE variable that is changed at a time. (AKA: Controlled Experiment) Controlled Variable/s – the variable/s that are purposely kept the same Manipulated Variable – the ONE variable that is deliberately changed (also called independent) Responding Variable – the variable that is observed and that changes in response to the manipulated variable (also called dependent) Experimental Group – the group in which the manipulated variable is changed Control or Control Group – the group used as a standard for comparison for the experimental group

14. Controlled Experiment Practice Hypothesis: Tomato plants given fertilizer will produce more tomatoes than plants that are not fertilized. Plant APlant B * Both plants are given the same soil, amount of water and sun, temperature, pot size, and growth time. * Plant B is fertilized once a week. What are the controlled variables, the manipulated variable, and the responding variable? Which is the control and the experimental group?

15. Answers Controlled Variables – soil, amount of water and sun, temperature, pot size, and growth time Manipulated Variable – fertilizer Responding Variable – # of tomatoes Control – Plant A Experimental Group – Plant B

16. Why change only one variable? Why did plant B grow more tomatoes? By only changing one variable, the experimenter can conclude that changes in the responding variable are due only to changes in the one manipulated variable. Plant B 7 hours of sunlight per day l L of water every 2 days gallon sized pot 35°C for 9 weeks fertilized once a week Plant A 5 hours of sunlight per day l L of water every 4 days quart sized pot 30°C for 6 weeks no fertilization Can’t tell!

17. Experimental Design Practice Describe why the experiment below is poorly designed. Write a prediction for the hypothesis and then re-design the experiment to make it better. Identify all variables and groups. Hypothesis: Bacteria exposed to antibiotics will be killed. Plate B Stored in incubator (35° C) Given ampicillin Stored in dark Given nutrients Plate A Stored on counter (22° C) Given penicillin Stored in light Not given nutrients

19. Recording and Analyzing Data and Results Data - observations and measurements that are made in an experiment –All experimental data must include units. (examples: 9cm, 20sec, 98°C) –Data is often represented using tables and graphs which must be thoroughly labeled. Two major types of measurements/observations: –Quantitative: data that can be measured in numbers. (Ex.: number of objects, dimensions, duration, mass, etc.) –Qualitative: data that is based on non- numerical descriptions. (Ex.: color, health, etc.)

20. Data Collected from an Experiment Storage Location Temperature Inside Room Temp Inside Freezing Temp Outside Winter Temp Percent of germinated seeds 0%80%85%

21. Representing Data in Graphs Storage Location Temp Percent of Germinated Seeds (%) 100 80 60 40 20 0 - Inside Room - Inside Freezing - Outside Winter Storage Temperature Effects on Seed Germination

22. Collecting & Representing Data Practice Using the data below, re-draw the data table and graph to improve them. Results: Frogs given caffeine jumped 27cm and frogs not given caffeine jumped 20 cm. Frog not given caffeine Frog given caffeine Distance of jump 2027

23. Choosing Bar vs Line Graphs –Bar graph = Used with a qualitative variable (groups/categories) –Line graph = Used for comparing two quantitative variables –Manipulated/independent variable always placed on X-axis, responding/dependent variable on Y-axis

24. Graph Examples Number of students per town… what kind of graph, bar or line? Town# of Students Canton9 Stoughton2 Norwood1 Westwood4 Dedham3 Milton2 Randolph1 Sharon1 Hyde Park1

25. Graph Examples Number of students at different heights… what kind of graph, bar or line? Height (cm)# of Students 1502 1512 1523 1536 1545 1553 1561 1571

26. Bar or Line Graph? Number of American Thrushes living in each of five forests 100 students’ choices for their favorite lunch Comparing the number of chromosomes to the number of genes The number of mates attracted by red vs yellow vs blue-beaked parrots The growth of a seedling (days old vs height)

27. Making Observations vs. Making Inferences Observation - Uses the senses to gather information. Inference - Logical interpretation based on prior knowledge and experience Example:: –You offer me a chocolate cookie. I say no thank you. –OBSERVATION: I did not eat the cookie –INFERENCE: I am on a diet, I do not like chocolate, I am not hungry, I am allergic to cookies…

28. Drawing Conclusions Conclusion – a final summation of experimental results –A conclusion’s main purpose is to evaluate your initial ideas (hypothesis & prediction) using your data Sometimes a hypothesis must be rejected leading to a new experiment or even a new hypothesis.

29. Draw Conclusions Example Based on the previous frog experiment. The experiment was designed to test whether caffeine would increase the distance frogs could jump. It was hypothesized that more highly caffeinated frogs would jump further. The results supported this, showing that frogs given caffeine jumped an average of 7cm farther than frogs that were not given caffeine. All other variables having been controlled, it can be safely concluded that caffeine increases jump distance in frogs. Experiments could also be done on other animals to see if caffeine would affect them or experiments could be done to see if frog jumps are affected by other types of chemicals.

30. Draw Conclusions Practice Examine the hypothesis and experimental results below, and write an appropriate conclusion. Hypothesis: Carrots require high nitrogen levels for best growth. Results: Carrots that were not given nitrogen grew to an average of 6 inches. Carrots given low levels of nitrogen grew to an average of 10 inches. Carrots given high levels of nitrogen grew to an average of 4 inches.

31. Communicate Results Scientists always report their results through journals and scientific papers. This allows others to skeptically evaluate their results, repeat their investigation, integrate their findings into other studies, and can lead to further questions and investigations.

32. Scientific Language The scientific process has a language of its own. –Sometimes, this language diverges from colloquial English. “Science words” can be different from English words even when they look exactly the same. For example, the words for different kinds of scientific outcomes and models:

33. Scientific Language Fact (Colloquial English): …? Fact (Scientific): An observation that has been made repeatedly. Example: Two negative poles move away from each other.

34. Scientific Language Law (Colloquial English): …? Law (Scientific): A description of patterns in a relationship between quantities. Example: p + q = 1, (p + q) 2 (Hardy- Weinberg’s Law)

35. Scientific Language Theory (Colloquial English): …? Theory (Scientific): A powerful explanation of related natural phenomena. Example: Matter is made up of atoms, properties of matter come from atomic behavior (Atomic theory)

36. Chapter 1-2: The Study of Biology Themes of Biology Honors Biology September 2011

37. What is Biology? The study of life in an organized and scientific framework Major Themes: –Unity and Diversity of Life –Interdependence of Organisms –Evolution –Stability and Homeostasis –Matter, Energy, and Organization

38. Unity and Diversity Living things are very diverse, yet all living things have many characteristics in common The “tree of life” places organisms that have more similar sets of genes on closer branches or lineages of the tree. –The “tree” has 3 main branches or subdivisions of living things called domains Bacteria, Archae, Eukarya –Domains are further divided into 6 kingdoms

39. Interdependence of Organisms Ecology is the study the interactions of organisms with one another and with their environment All organisms need substances such as nutrients, water, heat, and gases from the environment

40. Evolution Populations of organisms evolve or change over time. –Natural selection – organisms that have certain favorable traits are better able to successfully reproduce than organisms that lack these traits –Adaptations – some individuals have traits that give them an advantage for survival and reproduction and they pass them on to the offspring –Descent with Modification – is the gradual change in population over many generations caused by differential reproductive success

41. Stability and Homeostasis Living things maintain very stable internal conditions – called homeostasis – temp, water content and food intake

42. Matter, Energy and Organization Living things that have highly organized structures must be maintained by a constant supply of energy. Photosynthesis – captures the energy from the sun and changes it into a form of energy that can be used by other living things. –Autotrophs: Make their own food, able to change sunlight into energy rich substances. –Heterotrophs: Are organisms that must take in food to meet their energy requirement

43. Chapter 1-3: The Study of Biology Characteristics of Life Honors Biology September 2011

44. What does it mean to be alive? What characteristics make something living versus non- living? Brainstorm a list of characteristics that describe a living thing.

45. Characteristics of Living Things made up of units called cells organization metabolism: obtain and use materials and energy homeostasis: maintain a stable internal environment growth (cell division) and development reproduction are based on a universal genetic code (DNA) respond to their environment taken as a group, they change over time (evolve)

46. Living things are… made up of cells The cell is the smallest unit of life and all organisms are made of and develop from cells. Cells are a collection of living matter enclosed by a barrier that separates the cell from its surroundings –Unicellular – one celled –Multicellular – composed of more than one cell

47. Living Things… are organized

48. Living things… obtain and use materials and energy Metabolism: chemical reactions that build up and/or break down molecules. –Autotrophs: Make their own food, able to change sunlight into energy rich substances. Photosynthesis – captures the energy from the sun and changes it into a form of energy that can be used by other living things. –Heterotrophs: Are organisms that must take in food to meet their energy requirement

49. Living things… maintain internal balance Living things maintain very stable internal conditions – called homeostasis –temp, pH, water & salt content and food intake

50. Living things… grow and develop Growth: getting larger in size –Unicellular: cell gets bigger –Multicellular: get more cells Development: changes that occur during an organisms lifetime. (life cycles)

51. Living things… reproduce Reproduction – process where organisms produce new organisms or offspring. –Sexual Reproduction: information from two parents are combined to form the first cell of a new organism –Asexual Reproduction: information from one parent is divided in half to form new organism identical to the parent

52. Living things… are based on a genetic code Offspring resemble their parents DNA or deoxyribonucleic acid carries directions for inheritance

53. Living things… respond to the environment The environment (both living and nonliving parts) constantly changes Organisms must adapt or change to cope

54. Living things… evolve over time Populations of organisms evolve or change over time. –Natural selection, descent with modification