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Unit 1- The Science of AP Biology

Unit 1- The Science of AP Biology. Mrs. Stahl. Introduction to the Four Big Ideas. Big Idea 1- Evolution. Darwin (1809-1882): English Naturalist Studied and observed life for 30 years and then published “Origin of Species.”

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Unit 1- The Science of AP Biology

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  1. Unit 1- The Science of AP Biology Mrs. Stahl

  2. Introduction to the Four Big Ideas

  3. Big Idea 1- Evolution • Darwin (1809-1882): • English Naturalist • Studied and observed life for 30 years and then published “Origin of Species.” • His story began in 1831 (22 years old) when he took a five year trip on the HMS Beagle. • He observed that the characteristics of similar species varied somewhat from place to place-> lineages change gradually as species migrate from one area to another.

  4. Galapagos Islands • Located off the coast of Ecuador. • Main discovery = finches. • Discovered 14 species that were related, but they all had different beaks. • He stated that they derived from a common ancestor from the mainland. • Discovered that they ate different foods (island specific) which changed their beak shape. They had to adapt / change their beaks shape in order to survive and forage (hunt for food / eat).

  5. http://bio1100.nicerweb.com/Locked/media/ch14/galapagos.html

  6. Descent with Modification • The finches genes changed over time in order to adapt to the food source. If they didn’t adapt and change, they would die off.

  7. Other Observations • Plants and animals were similar on the little volcanic islands just like they were on the mainland. • Natural Selection = Main mechanism. The strong will adapt and survive. Those that don’t will die.

  8. Thomas Malthus- Influenced Darwin • Population of plants and animals tend to increase geometrically (increases by a constant factor) while humans increase their food supply arithmetically (increases by a constant difference) = limit on human survival. • What happens when the food runs out?

  9. Human growth = geometric Human food production = arithmetic

  10. Intrigued Darwin • Took the idea and his observations and saw that every organism can reproduce more offspring than can survive, but only a limited number actually do survive and produce viable offspring. • Those that have physical or behavioral attributes have the advantage = NATURAL SELECTION!

  11. Evidence of Natural Selection • 1. Fossil Record-> linked intermediate groups • 2. The age of the Earth, 4.5 bya • 3. Heredity- genes were passed on from generation to generation. The strong favorable ones. • 4. Comparative Anatomy- vertebrate bones are similar= common ancestor. • Homologous- same basic bones but they differ in structure and function. • Analogous- structures that are similar in function but differ in origin.

  12. Homologous Structures

  13. Analogous Structures http://bio3vo.wordpress.com/evolution/

  14. More Evidence • 5. Molecular- looking at patterns based on the sequencing of genes (genome). • Phylogenetic trees- family tree of genetics

  15. Big Idea 2- Energy and Molecular Building Blocks • 1. Free Energy: • Cellular Respiration and Photosynthesis. How this cycle is continual and vital for the movement of energy from food and sunlight to ATP (Adenosine Triphosphate). • Without these processes there would be no life on Earth. • Molecules and cells are used and recycled, and new cells grow and develop.

  16. 2. Compartmentalization- • Membranes are the first line of defense. • Create boundaries for protection, allow crucial processes such as photosynthesis and cellular respiration to occur. • Allows enzymes to function properly. Enzymes speed up rates of reactions so that processes can occur at a faster rate (maintain homeostasis).

  17. 3. Feedback Mechanisms: • Keep things normal or balanced • Positive Feedback loops are going to increase a needed reaction such as hibernation, nocturnal adaptations, and phototropism • Negative feedback loops focus on trying to keep internal conditions stable. • Ex- Shivering increases body temperature • Ex- Insulin is released when glucose levels are low • Ex- Sweating occurs to lower body temperature

  18. 4. Maintaining Homeostasis: • Constant internal balance • Adapt, migrate, or die

  19. 5. Timing, Coordination, and Regulation • Development from an egg • Has to have perfect timing and coordination of sex cells • Some result in apoptosis= cell death • Genetic Mutations • Plants telling the difference between dark and light • Organisms communicating with one another for migratory purposes as well as reproduction.

  20. Big Idea 3- Information, Storage, Transmission, and Response • DNA is the blueprint for life • DNA= Deoxyribonucleic Acid • Sequences of nucleotides make up our genes and millions of nucleotides make our chromosomes. • Cell Cycle allows growth and repair of DNA • Mitosis and Meiosis (Mitosis = body cells, Meiosis = gametes or sex cells) • Genetic Variation- increases diversity in a population. • Cell to cell communication and response • Cells are like little factories that process tons of information

  21. Big Idea 4- Interdependent Relationships • Interactions among populations: Symbiosis, prey/predator relationships, cell to cell interaction • Diversity- the more diversity the better • Flow of energy through food webs and food chains • How your cells, tissues, organs, and organ systems work together to function properly. • EX- Your heart would not be useful if it didn’t have blood and blood vessels. • EX- You wouldn’t be able to survive if plants weren’t around.

  22. Characteristics of Living Things • All living things must be able to: • 1. Reproduce • 2. Made up of cells • 3. Respond to a stimulus • 4. Grow and develop • 5. Evolve and change • 6. Metabolize- need and use chemical energy • 7. Maintain Homeostasis • 8. Made up of DNA

  23. Made up of Cells • Smallest and basic unit of life. • Each level builds on the level below it. • Ex- within a cell macromolecules are assembled into ribosome's, chromosomes, and membranes and they are then built upon to form organelles such as the mitochondria. Continues on to populations and species.

  24. DNA- Deoxyribonucleic acid • Stores genetic information • Made up of nucleotides (4 nitrogenous base pairs-AGCT), sugars, and phosphates. • Adenine (A) pairs up with Thymine (T) • Guanine (G) pairs up with Cytosine (C) • The sequence of the bases is what codes for the order of amino acids in the protein sequence (amino acids).

  25. Reproduction • Life has to come from prior life / DNA has to be passed on. • Living forms reproduce to generate others like themselves: binary fission, asexual reproduction, or sexual reproduction. • Genes replicate to form new genes • Cells divide to produce new cells- binary fission • Populations split up and new species are produced= speciation.

  26. Metabolism • Have to acquire nutrients from their environment in order to maintain proper energy levels. • Nutrients-> chemical energy for the body to use in the form of ATP. • Chemical processes include digestion, respiration, and synthesis of molecules. • Interaction between catabolic (destructive) and anabolic (constructive) • Cellular Respiration-> mitochondria • Cellular and nuclear membranes regulate metabolism by controlling the movement of molecules in and out of the cell.

  27. Growth and Development • All organisms have a life cycle that they go through from origin (when the sperm fertilizes the egg = fertilization) to adulthood. • Changes in size, shape, and differentiation in structures. • Unicellular are more simple than Multicellular. • Metamorphosis- many organisms have similar early stages of development and are hard to tell apart and then they change.

  28. Stimulus • How do they interact / respond with their environment? • Often referred to as ecology, focusing on geographic distribution and population abundance. • They respond by adapting their metabolism and physiology so that they can survive in the environment in which they live.

  29. Evolution • Change over time. • Ex- Darwin’s finches- he found 14 different species of finches that derived from one. They had different beaks to adapt to the type of seed they fed upon.

  30. Homeostasis • Maintaining constant internal conditions in an organism. Body temp. is 37 C or 98.6 F • Important because cells function best within a certain range of conditions. Temperature, blood sugar, acidity, must be controlled or it can be fatal. • Maintained-> negative feedback loop= change in a system causes a response that tends to return that system back to its original state.

  31. Ex- The control of blood sugar (glucose) by insulin is another good example of a negative feedback mechanism. When blood sugar rises, receptors in the body sense a change . In turn, the control center (pancreas) secretes insulin into the blood effectively lowering blood sugar levels. Once blood sugar levels reach homeostasis, the pancreas stops releasing insulin. http://anatomyandphysiologyi.com/homeostasis-positivenegative-feedback-mechanisms/

  32. Diversity of Life • Arises by evolutionary change leading to the present biodiversity we see. • Divided into three Domains: • 1. Bacteria- single celled prokaryotes (no nucleus) • 2. Archaea- single celled prokaryotes (no nucleus) • 3. Eukarya- Plants and Animals, complex organelles and multicellular.

  33. Taxonomy • Classifying Organisms http://www.charlesayoub.com/life-style/index.php/more/1/1018

  34. Domain Eukarya • 4 Kingdoms • 1. Kingdom Protista: unicellular eukaryotes, multicellular algae (dinoflagellates, diatoms, etc) • 2. Kingdom Plantae: have cells walls, cellulose, and obtain energy through photosynthesis. • 3. Kingdom Fungi: Cell walls are made of chitin, obtain energy by secreting enzymes and absorb the products they release. • 4. Kingdom Animalia- no cell walls, obtain energy by ingesting other organisms.

  35. Living Systems Show Hierarchical Organization • Life is highly organized • Begins with atoms and ends with the biosphere. • Cellular Level: Atoms-> Molecule-> Macromolecule-> Organelle-> Cell • Organismal Level: Tissue-> Organ-> Organ System-> Organism • Populational Level: Population-> Species-> Community-> Ecosystem-> Biosphere

  36. Cellular Level and Organismal Level http://sphweb.bumc.bu.edu/otlt/MPH-Modules/PH/PH709_A_Cellular_World/mobile_pages/PH709_A_Cellular_World8.html

  37. Populational Level http://eweb.furman.edu/~wworthen/bio111/102science1lec.htm

  38. Science Practices • Science Practice 1 • The student can use representations and models to communicate scientific phenomena and solve scientific problems. • Science Practice 2 • The student can use mathematics appropriately. • Science Practice 3 • The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course. • Science Practice 4 • The student can plan and implement data collection strategies in relation to a particular scientific question. (Note: Data can be collected from many different sources, e.g., investigations, scientific observations, the findings of others, historic reconstruction and/or archived data.) • Science Practice 5 • The student can perform data analysis and evaluation of evidence. • Science Practice 6 • The student can work with scientific explanations and theories. • Science Practice 7 • The student is able to connect and relate knowledge across various scales, concepts and representations in and across domains.

  39. Scientific Theory and Reasoning • Theory is used in two ways: • 1. Proposed explanation for some natural phenomenon, often based on some general principle. • Ex- Newton’s theory of gravity= brought together concepts that were previously thought to be unrelated.

  40. 2. Theory- body of interconnected concepts, supported by scientific reasoning and experimental evidence. • Ex-Quantum theory- brings together a set of ideas about the nature of the universe, explains experimental facts, and serves as a guide to further questions and experiments. • EX- Theory of Evolution

  41. The Scientific Method • A series of steps used to set up an experiment in order to test a hypothesis or solve a problem.

  42. Steps • Make an observation • Ask a question / Research • Form a hypothesis • Experimentation • Collect data / Results • Analyze and Conclude • Repeat

  43. Observation • Using your senses to study the natural world. • Can also use tools such as previous biological research and computers. • Inference= logical interpretation based on prior knowledge.

  44. Ask a Question • Do other sharks jump out of the water or just white sharks?

  45. Hypothesis • Not an EDUCATED GUESS- in science we don’t like to say that we are “guessing.” • Prediction based on prior knowledge. • Typically use the words If and Then!

  46. Inductive vs. Deductive • Logic flows in the opposite direction, from specific to the general. • Ex- If poodles have hair, and terriers have hair, and every dog that you observe has hair, then you may conclude that all dogs have hair. • General principles to predict specific results. • To the point. • Ex- If all mammals have hair, and you find an animal that does not have hair, then you may conclude that this animal is not a mammal.

  47. Example of a Hypothesis • If five plants are placed in the sunlight and five plants are placed in the darkness for 10 hours per day for 10 days, then the plant in the sunlight will grow taller.

  48. Experiment • Try to find the cause and effect relationship.

  49. Independent Variable • What you, the experimenter changes or manipulates. • Example- number of days in the sunlight, location of the plants.

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