AP BIOLOGY

1. AP BIOLOGY What to Expect?

2. What is AP Biology? • Curriculum is determined by the College Board • Goal is to prepare you for taking and passing the AP Exam on May 14, 2013.

3. Content Focus • The course content is structured around Four Big Ideas: • Evolution • Cellular Processes • Genetic and Information Transfer • Ecology

4. The Labs • The AP labs are inquiry based • Students will: • Generate questions for investigation • Choose which variables to investigate • Design and conduct experiments • Design their own experimental procedures • Collect, analyze, interpret and display data • Determine how to present their conclusions

5. The Exam • Two sections: multiple choice and free response. • 3 hours long: • 90 minute multiple choice (50% of grade) • 90 minute free-response section that begins with a mandatory 10 minute reading period (50% of grade)

6. Multiple Choice • 63 multiple choice questions • 6 grid in questions that will require calculations (four function calculators with square root are allowed)

7. Free Response • Two long free response questions (~7 points each: one of which will definitely be on inquiry lab design) • Six short free response questions (range from 3 to 6 points each)

8. Course Requirements • Notes: You will keep your own notebook. Notes will not count for a grade. They are for your reference. Study from them for the unit tests and for the exam prep. • Lab Notebook: All lab activities will be documented in a bound lab notebook. It will be formatted according to specific instructions and will be checked periodically for a grade. • Lab Reports: A formal lab report will be required (one per grading period) • Tests: Summative tests will be given at the completion of each unit. • Projects: TBA • Homework: You will be expected to complete reading assignments and homework on time.

9. The Big Ideas • Chapter 1 of your text talks about 7 underlying themes in the study of Biology. • The current AP course combines these themes into a more concise picture represented by four Big Ideas. • We will continually refer to these Big Ideas throughout the course. • Big Idea #1 is Evolution

10. Evolution: • The process of evolution drives the diversityand unityof life. • It is the process of change that has transformed life on Earth throughout history. “Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky

11. Charles Darwin • Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859. • Darwin made two main points: • Species showed evidence of “descent with modification” from common ancestors (this phrase shows unity in the kinship of species and diversity in the modifications that evolved) • Natural selection is the mechanism behind “descent with modification”

12. Darwin’s Observations • Darwin observed that: • Variationexists among individuals in a population • Traits are passed from parents to offspring • Overproductionexists in most species • Competitionis inevitable • Species generally suit their environment • Thus, individuals that are best suited to their environment are more likely to survive and reproduce. Overtime, more individuals in a population will have the advantageous traits.

13. In other words, the natural environment “selects” for beneficial traits Reproduction of survivors Population with varied inherited traits Elimination of individuals with certain traits Increasing frequency of traits that enhance survival and reproductive success

14. How do we define life? • So if Evolution is the core theme of biology, and helps to explain both the unity and diversity of life, then how do we define life? • What is a living thing?

15. What is Life? • Life defies a simple, one-sentence definition • Life is recognized by what living things do. • Properties of life include: • Order • Evolutionary adaptation • Response to environment • Reproduction • Growth and Development • Energy processing • Regulation response order adaptation regulation reproduction energy processing growth/ development

16. Biological Hierarchy • To study life, it is useful to divide it into different levels of biological organization in which new properties emerge at each level. biosphere cells systems/ organs ecosystems organelles communities atoms tissues populations molecules organisms

17. Emergent Properties vs. Reductionism • Emergent properties result from the arrangement and interaction of parts within a system • New properties emerge as levels increase • Ex: nerve cells “fire” but a brain “thinks” • Reductionism is the reduction of complex systems to simpler components • Ex: studying the molecular structure of DNA allowed us to discover how it could serve as the chemical basis of inheritance.

18. Systems Biology • An understanding of biology balancesreductionism with the study of emergent properties • This often involves systems biology, which constructs models for the dynamic behavior of whole biological systems. • Such models allow biologists to predict how a change in one or more variables will affect other components and the whole system. • This leads us to Big Idea #2: Cellular Processes

19. Cellular Processes: • Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis.

20. Structure and Function • “Form fits Function” is a guide to the anatomy of life. • Structureand functionof living organisms are closely related. • Ex: a leaf is thin and flat, maximizing the capture of light by chloroplasts

21. Fig. 1-6 The relationship between structure and function can be seen at all levels of biological hierarchy. (a) Wings: have aerodynamically efficien shape (b) Bones: wing bones are strong but lightweight Infoldings of membrane Mitochondrion 100 µm 0.5 µm (c) Neurons: specifically designed to transmit and carry signals necessary to coordinate flight (d) Mitochondria: energy for flight comes from the chemical reactions that are dependent upon the structure of the mitochondria

22. What are Cells? • The cellis an organism’s basic unit of structure and function • Two basic types: • Eukaryotic: contain an nucleus and membrane-bound organelles • Prokaryotic: no nucleus or membrane-bound organelles

23. All cells are enclosed by a membrane that controls what gets in and what gets out • All cells use DNAas their genetic information • The ability of cells to divideis the basis of all reproduction, growth and repair of multicellular organisms.

24. Cell Communication • Cells of multicellular organisms must also be able to communicate. • Chemical feedback mechanisms regulate many biological systems • These chemical pathways are catalyzed by enzymesand allow biological processes to self-regulate.

25. Negative vs. Positive Feedback • Negative feedback means that as more of a product accumulates, the process that creates it slowsand lessof the product is produced. • Ex: ATP production (When a cell makes more ATP than it can use, the ATP “feeds back” and inhibits an enzyme at the beginning of the pathway.) • Positive feedback means that as more of a product accumulates, the process that creates it speeds up and moreof the product is produced • Ex: Blood clotting (Platelets aggregate at a damaged blood vessel. They release chemicals that attract more platelets to the site.)

26. Fig. 1-13 A Negative feedback  Enzyme 1 As product D accumulates, it inhibits enzyme 1, thus slowing down production of more D. B D Enzyme 2 Excess D blocks a step D D C Enzyme 3 D (a) Negative feedback W Enzyme 4 As product Z accumulates, it stimulates enzyme 5, thus speeding up the production of more Z X Positive feedback + Enzyme 5 Excess Z stimulates a step Z Y Z Z Enzyme 6 Z (b) Positive feedback

27. Cell Communication through Generations • Cells also must be able to transfer information from one generation to another. • This leads us to Big Idea #3: Genetics and Transfer of Information.

28. Genetics and Transfer of Information: • Living systems store, retrieve, transmit, and respond to information essential to life processes.

29. DNA • The continuity of life is based on heritable information in the form of DNA • Chromosomescontain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid) • Genesare the units of inheritance that transmit information from parents to offspring.

30. DNA Structure and Function • Each chromosome has one long DNA molecule with hundreds or thousands of genes • DNA is inheritedby offspring from their parents and controls the development and maintenance of organisms.

31. Fig. 1-9 Sperm cell Nuclei containing DNA Embryo’s cells with copies of inherited DNA Fertilized egg with DNA from both parents Egg cell Offspring with traits inherited from both parents

32. The Double Helix • The molecular structure of DNA accounts for its ability to store information • Each DNA molecule is a double helix made of building blocks called nucleotides.

33. Fig. 1-10 Nucleus DNA Nucleotide Cell (a) DNA double helix (b) Single strand of DNA

34. A particular sequence of nucleotides is called a gene. • Genes control protein production indirectly, and different proteins control different cell activities. • Thus, DNA provides the blueprints, and proteins serve as the toolsthat actually build and maintain the cell and carry out its activities.

35. The role of the Environment • Communication goes beyond the cellular level • Organisms must also communicate with each other and interact with their environment. • This leads us to Big Idea #4: Ecology

36. Ecology: • Biological systems interact, and these systems and their interactions possess complex properties.

37. Ecosystem Dynamics • Every organism interactswith its environment, including nonliving factors and other organisms. • Bothorganisms and their environments are affected by these interactions. • The dynamics of an ecosystem include two major processes: • Cycling of nutrients, in which materials acquired by plants eventually return to the soil • Flow of energy from sunlight to producers to consumers.

38. Fig. 1-5 Sunlight Ecosystem Energy flows through an ecosystem, usually entering as sunlightand exiting as heat while chemical nutrients recyclewithin an ecosystem. Producers (plants and other photosynthetic organisms) Cycling of chemical nutrients Heat Chemical energy Consumers (such as animals) Heat

39. All organisms must perform work, which requires energy. • Energy can be stored in different forms, for example, light, chemical, kinetic, or thermal • The energy exchange between an organism and its environment often involves energy transformations

40. Inquiry Science • The other main shift in the focus of the AP curriculum is the emphasis now placed on inquiry science. • The word Scienceis derived from Latin and means, “to know” • Inquiryis the search for information and explanation. • There are two main types of scientific inquiry: discovery science and hypothesis-based science

41. Discovery Science • Discovery science describes natural structures and processes • This approach is based on observationand the analysis of data (both qualitativeand quantitativedata) • Inductive reasoning can be used to draw conclusions based on the observations made. • Ex: The sun always rises in the east • Ex: All organisms are made of cells

42. Hypothesis-Based Science • Observations can lead us to ask questions and propose hypothetical explanations called hypotheses • A hypothesis is a tentative answer to a well-framed question • A scientific hypothesis leads to predictions that can be tested by observation or experimentation • A hypothesis must be both testableand falsifiable

43. Deductive Reasoning • Deductive reasoning is used more in Hypothesis-based science. • It uses general premises to make specific predictions (start with the general knowledge and extrapolate the specific results) • Ex: If organisms are made of cells (premise 1), and humans are organisms (premise 2), thenhumans are composed of cells (deductive prediction)

44. The Scientific Method • The scientific method is an idealizedprocess of inquiry • Hypothesis-based science is based on the “textbook” scientific method but rarely follows all the ordered steps. • Discovery science has made important contributions with very little dependence on the so-called scientific method.

45. Designing Controlled Experiments • A controlled experiment compares an experimental group with a control group • Ideally, only the variable of interest differs between the control and experimental groups • A controlled experiment means that control groups are used to cancel the effects of unwanted variables • A controlled experiment does notmean that all unwanted variable are kept constant (this is actually impossible in field studies) • Read Snake mimicry case study in textbook pgs. 20-22

46. Limitations of Science and Scientific Theories • In science, observations and experimental results must be repeatable • Science cannot support or falsify supernatural explanations, which are outside the bounds of science. • In the context of science, a theory, is: • Broader in scope than a hypothesis • General, and can lead to new testable hypotheses • Supported by a large body of evidence in comparison to a hypothesis

47. Science, Technology, and Society • The goal of scienceis to understand natural phenomena • The goal of technologyis to applyscientific knowledge for some specific purpose • The two are interdependent • Many ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology. • This course will explore some of these types of ethical issues.