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Biology 105, Chapter 1 slide share


  • 1. Chapters 1 - 3 Biology Basics Scientific Method and Chemistry

2. Biology is a science Science c.1300, "knowledge (of something) acquired by study," also "a particular branch of knowledge," from O.Fr. science, from L. scientia "knowledge," from sciens (gen. scientis), scire "to know," probably originally "to separate one thing from another, to distinguish," Modern sense of "non-arts studies" is attested from 1678. Main modern (restricted) sense of "body of regular or methodical observations or propositions ... concerning any subject or speculation" is attested from 1725; in 17c.-18c. Harper On-line Etymology Dictionary **One of my FAVORITE resources for better understanding of terms** 3. Since biology a science, it is about knowledge based on methodical observation Biologists attempt to exclude subjective measures such as opinion and emotion from their studies 4. Pseudoscience is defined as a body of knowledge, methodology, belief, or practice that is claimed to be scientific or made to appear scientific, but does not adhere to the scientific method, lacks supporting evidence or plausibility,or otherwise lacks scientific status. 5. How to identify pseudoscience Use of vague, exaggerated or untestable claims Over-reliance on confirmation rather than refutation Lack of openness to testing by other experts Lack of progress Personalization of issues Use of misleading language 6. Examples of Pseudoscience See Web Task Week 1 Apollo moon landing hoax accusations Astrology Creation science Crop circles Crystal healing Dianetics Dogon people and Sirius B Face on Mars Homeopathy Lunar effect Paranormal subjects Channeling, Dowsing, Electronic voice phenomenon , Extra-sensory perception, Levitation, Materialization Psychic surgery Sances Psychokinesis Therapeutic touch Perpetual motion Quantum mysticism Ufology The Bermuda Triangle Pseudoarchaeology Animal mutilations Tutankhamun's curse Tunguska event Graphology Phrenology Primal therapy Subliminal perception Anthroposophic medicine, Applied kinesiology Attachment therapy Bates method for better eyesight Biorhythms Brain Gym Electromagnetic Hypersensitivity (EHS) Faith healing Hypnosis Iridology Magnetic therapy Maharishi's Ayurveda. Radionics Scientific racism Traditional Chinese Medicine. Shroud of Turin Hongcheng Magic Liquid Laundry balls Stock market prediction 7. Biology is the study of life So, what does it mean to be alive Our next discussion will be the properties of living things What things are living? Bacteria, amoebas, algae, fungi, plants, corals, sponges (in the ocean), animals, viruses (maybe) 8. Properties of Living Things Life is surprisingly difficult to define Many characteristics of life also exist in some nonliving things Wind can move under its own power Crystals and fire can grow Water responds to its environment Ludwig von Bertalanffys cell experiment If I take a living cell and blend it in a blender, it is no longer alive However, chemically nothing has been added or deleted All the chemicals are the same, but the cell is no longer alive. Life is not the components but the organization of the components A system where the whole is greater than the sum of the parts Life is an emergent property whose behaviors cannot be predicted solely from the lower level components that make it up 9. 1: Organization Living things are separated from their environment by a lipid (fat) based membrane Living things are cells, or are made of cells Therefore in the list below, the smallest level that is truly living is the cellular level Living things show organization Organization Hierarchy of living things Atoms, Molecules, Macromolecules, Organelles, Cells, Tissues, Organs, Organ Systems, Organisms, Populations, Communities, Ecosystems, Biomes, Biospheres Organization is partly about division of labor which provides efficiency and allows organisms to grown larger than would otherwise be possible 10. 2: Acquire & metabolize nutrients and assimilate & use energy Nutrients Oxygen and other gases Depends on the organism*** Carbohydrates Lipids Some of which are known as fats Proteins Nucleic Acids Vitamins & Minerals Water The most commonly omitted nutrient Metabolism has 2 parts Anabolism building of molecules from component parts Catabolism breaking down molecules into their components Organisms catabolize nutrients to get the building blocks for anabolism of substances they need 11. 3: Irritable - Respond to stimuli and the environment Organisms move toward water, food and shelter Organisms move away from dangerous conditions such as predators and environmental hazards (heat, cold, chemicals, sun) Organisms react to changes in their environments 12. 4: Maintain homeostasis A relatively constant or unchanging internal environment Change is monitored and controlled by means of feedback loops Variables that are regulated to maintain homeostasis include Nutrient content (see #2 for examples of nutrients) Temperature On a larger scale blood flow, heart rate, breathing rate, etc. 13. 5: Reproduction and Genetic Material Living things contain genetic material called DNA (deoxyribonucleic acid) and/or RNA (ribonucleic acid) Living things reproduce by copying of their DNA and division of their cells DNA provides the instructions for making all the proteins found in living things Reproduction is the ultimate goal of all living things it is their driving force and influences all their other functions 14. 6: Growth and Development Living things get larger over time Living things go through phases of change over time as they prepare for reproduction 15. 7: Adaptation and Evolution Individuals can undergo small changes to acclimate to their environment These changes are NOT passed on in their genes For example: leaves on the sunny side of a tree are typically thicker than the leaves on the shady side Populations adapt through changes in their gene pool as some genetic strains survive better than others For example: when the industrial revolution occurred localized populations of grey moths survived more often than white moths Species evolve over time as certain populations adapt, survive, and reproduce better than others 16. Viruses living or non-living? Viruses are made of DNA or RNA surrounded by a protein coating They have no cell membrane (and therefore are not cells) They cannot reproduce by themselves They must use the machinery of their hosts cells They dont metabolize or use energy They dont maintain homeostasis 17. Studying Science Using the Scientific Method The scientific method provides a common set of rules through which we can gain knowledge. In order to be able to use the method your research must meet these conditions: Observable: given the proper equipment anyone should be able to see the same results as the researcher Measurable: results must be able to be OBJECTIVELY counted Verifiable: the results must be repeatable Falsifiable: there must be a way to be proven wrong 18. The Process of the Scientific Method 1. Observation Researchers are aware of the world around them and CURIOUS They are thinking hmmmhow does that work, why did that happen, what if I did this differently? These curiosities do NOT have to be biologically mind-blowing, just thoughtful Marys examples I noticed that my pet turtle eats more fish in the summer than in the winter I notice that my son is more energetic after a long night of sleep than a short one I notice that more people order chicken nuggets if they have kids with them than if they are alone in the car 19. 2. Forming a Hypothesis This is an EDUCATED guess You must either do some research or have some experience with the subject you have observed Your guess should only suggest a SINGLE explanation for the phenomenon you observed Marys examles My turtle eats more in the summer because his tank is hotter (and this somehow affects his metabolism so he needs more food) The amount of time my son has the energy to play is controlled by the amount of time he sleeps The more kids that are in a car the more orders of chicken nuggets they will purchase 20. 3. Experiment To set up an experiment you need to consider several variables (changeable factors) You will create at least 2 groups when you generate the idea for an experiment The control group and the experimental group(s) 21. CONTROL GROUP the norm, it serves as a basis for comparison Marys examples My turtles eating habits when his tank is 70 My sons playing time when he has slept for 8 hours The number orders of chicken nuggets per car when no kids are in the car EXPERIMENT GROUP(S) you change the main or INDEPENDENT variable to test your hypothesis Marys examples My turtles eating habits when the tank is 80 (group 1); My turtles eating habits when the tank is 90 (group 2); etc. (try not to boil the turtle ) My sons playing time when he has 6 hours of sleep (group 1); 5 hours of sleep (group 2); etc. The number of order of chicken nuggets per car when there is/are 1 kid; 2 kids; 3 kids; etc. 22. The Variables things that could possibly change in your experiment either through your action or without your action you need to consider them all Independent variable This is the thing you are changing and it is your explanation from your hypothesis My examples: The temperature of the tank The number of hours of sleep The number of kids in the car Dependent Variables This is the thing you will measureresearchers hope their INDEPENDENT variable will influence their DEPENDENT VARIABLE as expected that means they were right! My examples: How many fish turtle eats (hopefully more as it gets warmer) How much playing time my son can tolerate before he falls asleep (hopefully more when he gets more rest and less when he gets less rest) How many orders of chicken nuggets are requested per car continued on the next slide.. 23. Control Variables Since we want to FOCUS on the independent and dependent variables we want to try to eliminate all the confounding factors that could get in the way of our understanding we want to control these outside influences My examples: I will use all MALE turtles, they will always be OFFERED 10 fish, they will always get 1 INCH GOLDFISH, they will all live in a 5 gallon TANK, they will always have a 10 hour DAY LENGTH, etc. I will use only my son as a study SUBJECT, he will always have 3 days of NORMAL sleep patterns before I start an experimental day, he will always start by eating 1 cup of CHOCOLATE CEREAL, he will always have 10 minutes of ACTIVE TIME per hour (jumping jacks or running), etc. I will always observe cars at McDonalds (LOCATION), I will observe them from 11 am 1 pm (TIME), I will only observe vehicles with female drivers (GENDER), I will only observe vehicles with drivers from the AGE of 30-40, etc. 24. 4. Data analysis This usually involves some statistics to allow you to objectively compare the data you have collected It is not based on the researchers perceptions of the data Data is often represented graphically The independent variable should be placed on the X- axis (along the bottom) The dependent variable should be placed on the Y-axis (along this side 25. Turtle Feeding Habits 0 2 4 6 8 10 12 60 65 70 75 80 85 Temperature FoodEaten(#ofFish) 26. 5. Conclusions If your data does not support your hypothesis Reject your hypothesis you are wrong If your data does support your hypothesis Do not reject your hypothesis you are not wrong But you arent necessarily right either Remember, you have to be able to verify or repeat these results so you have to continue to research to make sure you have good confidence in your hypothesis 27. Levels of Confidence Hypothesis An educated guess, keep working! Theory A well supported hypothesis (a proposed explanation of an observed phenomenon) Generally a theory has some unanswered questions, potential flaws, or other concerns Examples of theories Cell theory, biogenesis theory, atomic theory, big bang theory, global climate change, theory of relativity Law A description of an observed phenomenon Usually scientific laws refer to rules for how nature will behave under certain conditions. Scientific theories are more overarching explanations of how nature works and why it exhibits certain characteristics. (Wikipedia theory) A common misconception is that scientific theories are rudimentary ideas that will eventually graduate into scientific laws when enough data and evidence has been accumulated. A theory does not change into a scientific law with the accumulation of new or better evidence. A theory will always remain a theory, a law will always remain a law. Examples of laws Law of gravity; laws of conservation of mass, energy, and momentum; laws of thermodynamics; gas laws; electromagnetic laws 28. From But it's "JUST a THEORY" Version 1.0 Copyright 1999 by Ken Harding [last update August 24, 1999] Is Evolution a fact or a theory? The theory of evolution explains how life on earth has changed. In scientific terms, "theory" does not mean "guess" or "hunch" as it does in everyday usage. Scientific theories are explanations of natural phenomena built up logically from testable observations and hypotheses. Biological evolution is the best scientific explanation we have for the enormous range of observations about the living world. Scientists most often use the word "fact" to describe an observation. But scientists can also use fact to mean something that has been tested or observed so many times that there is no longer a compelling reason to keep testing or looking for examples. The occurrence of evolution in this sense is a fact. Scientists no longer question whether descent with modification occurred because the evidence supporting the idea is so strong. Why isn't evolution called a law? Laws are generalizations that describe phenomena, whereas theories explain phenomena. For example, the laws of thermodynamics describe what will happen under certain circumstances; thermodynamics theories explain why these events occur. Laws, like facts and theories, can change with better data. But theories do not develop into laws with the accumulation of evidence. Rather, theories are the goal of science. WATCH FOR AN UPCOMING EXTRA CREDIT DISCUSSION ON THEORIES AND LAWS!!!


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