Bio 112 5th EditionExam # 1 Study Guide Lectures1) Lecture #1: What is Science and How is it Done?a) Science is a body of knowledge, or a collection of facts, but the knowledge is constantly changingi) Scientific theory defined(1) Theory: explanation of a broad range of related natural events and observations which is based on repeated tests of hypothesesii) Process: the way we gain knowledge2) Lecture #2: The Scientific Method and Biogeochemical Cyclesa) Scientific method i) Hypothesis(1) Possible explanation of a natural event or observationii) Prediction(1) Proposal or claim of what testing will show if a hypothesis is correctiii) Experimental test(1) Controlled procedure to gather observations that can be compared to predictioniv) Control group(1) Standard to compare test group againstv) Variable(1) Aspect of an object or event that may differ with time or between subjectsvi) Conclusion(1) Statement that evaluates a hypothesis based on test resultsb) Null hypothesisi) Independent variable does not affect dependent variable.(1) Independent variable: variable that is being manipulated(a) When graphing, independent variable is on the x-axis(2) Dependent variable: variable that is being measured(a) When graphing, dependent variable is on the y-axisii) Example null hypothesis: The amount of books one reads does not affect intelligence(1) IV: amount of books read(2) DV: intelligencec) Food mattersi) The rising costs of health care in the US limits individuals’ budget for food(1) Diseases such as heart disease and diabetes have become more common in recent yearsii) 19% of America’s fossil fuels are used to transport food(1) Causes US to be more dependent on fossil fuelsd) Biogeochemical cyclesi) This is where your food beginsii) Carbon cycle(1) Atmosphere  plants  consumers  back to atmosphere(2) Natural pathways, such as photosynthesis and respiration, release atmospheric carbon (CO2)(3) Human activities, such as drilling and the extraction of oil, also release CO2iii) Nitrogen cycle(1) Soil plants  consumers (2) Natural nitrogen fixation(a) Gaseous nitrogen (N2) must be fixed by bacteria to be usable by plants  NH4+(3) Industrial nitrogen fixation(a) Burning of fossil fuels to generate high temperature and pressure, combine N2 and H2 to make ammonium compounds (NH4)(4) Other ways to complete the nitrogen cycle(a) Fertilizer: the Haber-Bosch process(i) Electricity is used to perform the nitrogen cycle(b) Cover crops(i) Plant soybeans one year, plant clover the following year(c) Intercropping(i) Two plants sharing the same space, 1 is fixing N2(d) Natural fertilizer(i) When chickens poop, NH3 is released into the soil, which is a natural fertilizeriv) Carbon affects the quantity of life, while nitrogen affects the quality of life(1) Humans get nitrogen from eating plants and other animals (a) Nitrogen is a major component of proteins (brain, muscle, hair) and DNA3) Lecture #3: The Omnivore’s Dilemmaa) Photosynthesisi) Free solar energy(1) Capture in food product (plant or animal) and turn into human energyii) Sugar production(1) Plants make their own food during photosynthesis, known as glucoseb) Food chains contain inputsi) Types of food chains(1) Industrial food chain(a) Contains many inputs: fertilizers, growth hormones, transportation, etc. (b) Soil  human, but must encounter many inputs before reaching human(c) Reliant on fossil fuels for transportation(d) The majority of our food supply is produced by an industrial food chain(e) Takes a little more than a year for a corn fed cow in an industrial food chain toreach adulthood(2) Big organic food chain(a) Contains less inputs when compared to an industrial food chain(i) Inputs used within a big organic food chain are natural(ii) No growth hormones, antibiotics, fertilizers, or synthetic nutrients(b) Relies on fossil fuels for transportation of food products(3) Pastoral food chain(a) Tries to emulate a natural system(i) Cows and other animals can live naturally and experience interactions with other animals(ii) Cows in pastoral food chains and big organic food chains are fed grass andtake about 5 to 6 years to reach adulthoodc) Decomposition yields NH3i) The process of breaking down organic material into simpler formsii) Puts nutrients back into the soild) Carrying capacityi) Some combination of factors limits the population growth for any organismii) Limiting factors for human population:(1) Fresh water, land space, etc.4) Lecture #4: The Stuff We’re Made Ofa) An element is a pure substance that cannot be broken down by a natural sourcei) Periodic Table of Elementsii) Elements are the building blocks for your body and your foodb) Critical components for human cellsi) Carbonii) Oxygeniii) Hydrogeniv) Nitrogenc) Isotopesi) Atomic forms of an element with different number of neutrons and different atomic weights(1) Example: 12C and 14C ii) Carbon isotopes exist in the atmosphere(1) Abundance of 12C (carbon-12) in atmosphere(2) Very little 13C (carbon-13) in atmosphered) The bonding of atoms creates moleculesi) Water is a compound (H2O)(1) Two hydrogen atoms and an oxygen atomii) Molecules form because an atom is most stable when its outer shelled is fillede) Covalent bondsi) Strongest of all bondsii) Electrons are shared between two atoms(1) Example: H2 or CO2f) Ionsi) Atom with a positive or negative charge due to an imbalance in the number of protons and electronsii) Ions form ionic bondsg) Ionic bondsi) Stronger than a hydrogen bond, but weaker than a covalent bondii) Electron is donated to another atom which yields positive and negative charged ions(1) Example: NaCl, also known as table salth) Chemical effects of ionsi) pH(1) pH refers to the relative concentration of H+ in fluids(2) Proteins and other biological molecules can only operate within a narrow pH range(3) pH of less than 7 is acidic(a) pH range of 0 to 6(4) pH of 7 is neutral(5) pH of more than 7 is basic(a) pH range of 8 to 14i) Hydrogen bondsi) Weak bonds between a positive hydrogen (H+) and a negative oxygen (O-)ii) Weakest of all bondsiii) Vital in biological molecules, like wateriv) Heat is lost when bond breaks as water evaporates(1) Example: sweating5) Lecture #5: The Stuff We Eat and More of the Stuff We’re Made Ofa) Important biological compoundsi) Carbohydratesii) Lipidsiii) Proteinsiv) Nucleic acidsb) An organic compound contains C (carbon) and H (hydrogen)c) Carbohydratesi) Simple sugars(1) Monosaccharide(a) Mono =