BIOLOGY 111 1st Edition Lecture 2 Outline of Last Lecture I. Introduction to Biology II. Levels of OrganizationIII. Reductionist (advantages and disadvantages)IV. Biology SystemsV. CellVI. EvolutionOutline of Current Lecture I. MethodsII. ReasoningsIII. ExperimentationIV. Scientific TheoryV. Overview of Chemistry and Physics Current LectureInitial scientific investigations are characterized as descriptive or discovery meaning an event of phenomenon is observed for hours, days, weeks, months or even years just to gather enough data and record enough observations to gain insight and with the goal to describe/define said event or phenomenon.Hypotheses based research, in order to be useful, must be testable (to check validity) AND falsifiable (opportunity to be proven n ot true). In forming a hypothesis, we are predicting the causes and explanations for events. If the hypothesis is given a chance to fail (through experimentation) , but doesn’t, the hypothesis is then strengthened. Keep in mind, however, that just because a hypothesis is accepted, that does not meant that is the ONLY TRUE hypothesis or explanation. Reasoning- Inductive reasoning – derives generalizations after collecting and analyzing observations - Deductive reasoning – used after the hypothesis has been made, and instead of a general conclusion, we conclude more specifically. ExperimentationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.*in biology most experiments are controlled Controlled experiments are designed to keep everything constant (i.e. environment) except for the experimental group, in which, only one factor is changed.- Control group – used as the basis for comparison in an experiment, kept constant- Experiment group – the group that has changed factor that is being tested/measuredScientific TheoryI. What’s the question?II. What’s the hypothesis?III. Experiment conductedA. What’s the control?B. What’s the dependent variable?C. What the independent variable?IV. What is the conclusion?Chapter 2Biology is based on the basic principles of Chemistry and Physics*Physics because we abide by the many laws (thermodynamics, energy, gravity…)*chemistry because EVERYTHING is made up of carbon and atomsi.e. ants secrete formic acid (CO2H2)SMALL changes in a molecule have a BIG effect on organismsi.e. the differences in functional groups of Estradiol (female) and Testosterone (male)ALL life forms are made up of Matter – anything that takes up space and contains space and is composed of elementsThere are 4 elements that make up 96% of organisms1. Oxygen2. Carbon (most important)3. Hydrogen4. Nitrogen (most abundant in the atmosphere)There are other elements that are also critical and that make up about 4%i.e. calcium, sodium, magnesium…And then there are trace elements that make up about .01%i.e. copper, iron, zinc, tin…*all of the most important elements of life can be found in the first 3 valence shells (rows) on the periodic table- Valence shell – outermost electron shell- Valence electrons – outer, unpaired electrons that are available to make bonds with other atoms containing unpaired electronso Hydrogen has one valence electrono Oxygen has twoo Nitrogen has threeo Carbon has four valence electrons*the number increases as you move from left to right on the periodic table*the more bonds that can be made (the more valence electrons), the more desirable*an atom with a complete valence is unreactive, meaning it will not react readily with other atoms… these atoms are said to be “inert” (chemically unreactive) Covalent bonds – formed by the sharing of a pair of valence electrons by two atoms*most stable bonds to be formed- Single bond – pair of shared electrons by two atoms- Double bond – two pairs of shared electrons between to atomsMolecule – two or more atoms held together by covalent bondsElements – pure substances that cannot be destroyed or broken down to other substances by chemical reactions (chemists recognize there to be 92 occurring in nature). Compound – a substance consisting of two or more different elements combined in a fixed ratio*each contain very different properties from the individual elements that construct itAtoms – smallest unit of matter that still retains the properties of an element*the structure determines element propertiesThe #protons (+charge) = the #electrons (-charge)- Protons – positively charged- determines the element- represent the atomic number (A) for a element- Electrons – negatively charged - Determines chemical behavior- Neutrons – neutral (no charge)- Determines isotopes (differing forms of the same element having the same number of protons but different number of neutrons)*adding the protons and neutrons gives the mass numberCarbon Dating determines the age of an object based on the decay rate of carbon in the objecti.e. C12 isotope stays because its most stable, whereas, C14 decays within 60,000 yearsEnergy*b/c energy cannot be created nor destroyed, it is converted between potential and kinetic - Potential energy – stored energy in matter based on location and structureo Begins maxed out (sitting at the top of the slide)o Decreases as it is used and converted into kinetic energy (sliding to the bottom)- Kinetic energy – used energy (sitting at the bottom of the slideAtoms have stored energy and varies based on its valence shells- Third valence shell (furthest from nucleus, highest energy level) can hold up to 8 electrons (potential energy state)- Second valence shell (midway from nucleus, medium energy level) can hold up to 8 electrons- First valence shell (closest to the nucleus, lowest energy level) can hold up to 2 electrons(kinetic energy state)*as you move outward from first valence shell to the third, energy is absorbed (increase potential energy and decrease kinetic energy) *as you move inward from third valence shell to the first, energy is released (decrease potential energy and increase kinetic energy)Electron OrbitalsThe three-dimensional space where an electron is found 90% of the time- First shell is 1s orbital ( which can hold 2 electrons)- Second shell is 2s orbital and three 2p orbitals (which holds 8 electrons, 2 per