Microscopic : atoms, molecules, organelles, etc.Macroscopic: tissues, organs, organism, population, community, ecosystem, biosphereInterdependency among organismTrophic pyramidReproduction, Growth, and DevelopmentEvolutionary Adaptations2. Hierarchy of Living SystemsCellular levelAtoms, molecules, organelles, cellsOrganismal levelTissues, organs, organ system, organismPopulation levelBIOL 120 1st EditionExam # 1 Study Guide Lectures 2-8Lecture 2 1. What classifies an organism as living?- Consist of one or more cells - Energy Utilization  Have a metabolism (used to grow and reproduce)- Sense and respond to their environment o Use homeostasis maintain internal environment - Cellular Organizations o Microscopic : atoms, molecules, organelles, etc.o Macroscopic: tissues, organs, organism, population, community, ecosystem, biosphere- Interdependency among organism o Trophic pyramid- Reproduction, Growth, and Development - Evolutionary Adaptations 2. Hierarchy of Living Systems - Cellular levelo Atoms, molecules, organelles, cells- Organismal levelo Tissues, organs, organ system, organism- Population levelo 1. Population: a group of individuals of the same type in an areao 2. Species: all populations of a particular kind of organismo 3. Community: population of different species living together in one placeo 4. Ecosystem: physical environment and the community (living and nonliving)o 5. Biosphere: Earth’s region where organisms can exist3. Scientific Enquiry- Science aims to understand the natural world through observation and reasoning descriptive and precise - Deductive reasoning: uses general principles to make specific predictions- Inductive reasoning: uses specific observations to develop general conclusions- Scientific method o Observationo Hypothesis formationo Prediction o Experimentation o Conclusion 4. Cells and Cell Theory- Cell Theory: all organisms are made of cells and all cells come from preexisting cells o Discovered by Louis Pasteur - Cell: a highly organized compartment bounded by a plasma membrane 5. Theory of Evolution - Evolution: a change in the characteristics of a population over time o Natural selection aids evolution o Phylogenetic tree: a graphical representation of the evolutionary relationships among species o Natural selection acts on individuals  evolution acts on a population o Two conditions must be met for natural selection in populations to occur Individuals must vary in characteristics Some of these characteristics must help individuals survive or reproduce more than other traits o Fitness: the ability of an individual to produce offspringo Adaptation: a trait that increases the fitness of an individual in a particular environment o Artificial Selection: Repeating the selection process over generations results in changes in the characteristics of a domesticated population over time (breeding)- Using molecules to understand the tree of live (evolution)o Uses DNA to make connections on the phylogenetic treeo 3 main groups Eukarya- Plantae- Fungi- Animalia- Protista Bacteria  Archaea 6. Basic Atomic Structure - Matter: anything that occupies space and has mass (solid, liquid, gas)- Element: a substance that can’t be broken down into another substance by chemical reactions- Atomic number: number of protons in the nucleus - Atomic mass: the number of protons and neutrons - Isotopes: an atom with the same number of protons, but a different number of neutronso i.e. Carbon has 6 p and 8n  At. Wt. = 14 and Carbon has 6 p and 6 n  At. Wt. = 12- Protons: positively charged particles- Neutrons: neutral particles- Electrons: negatively charged particles - Molecule: a substance made from two or more atoms of similar or different types (form when atoms bond to each other)o Most important to life is water because it forms hydrogen bonds - Energy: the capacity to do work or supply heat and is either stored potential energy or active motion - Chemical energy: potential energy that is stored in chemical bonds (ATP)- Thermodynamics: o 1st law: energy cannot be created or destroyedo 2nd law: spontaneous natural processes increase entropy overall 7. Chemical Bonds- Atoms gain or lose electrons in order to be stable o Valence electron: electrons in the outermost shello Valence: number of unpaired electrons in an atom- Chemical reaction: when an atom gives up, gains, or shares one or more electrons with another atom- Covalent Bond: each atom’s unpaired valence electrons are shared by both nuclei to fill their orbitalo Non polar- equal electronegativityo Polar- unequal electronegativityo- Ionic bond: results from the attraction of a cation and aniono Ion: an atom or molecule that carries a charge from either losing or gaining an electrono Cation: an atom that loses an electron and becomes positively chargedo Anion: an atom that gains an electron and becomes negatively charged 8. Representing Molecules- Molecular formula: indicate the numbers and types of atoms in a molecule - Structural Formula: indicate which atoms are bonded together and whether the bonds are single, double, or triple- Ball and Stick models and space filling models: shows #D geometry o9. Water- Most important chemical property  can form hydrogen bonds - A great solvent  due to the covalent bonds being polar it can bond to other atoms - Hydrogen bonds: the weak electrical attractions between the partially negative oxygen of one molecule and the partially positive hydrogen of a different water moleculeo Hydrophilic: can dissolve; “water loving” i.e. sugaro Hydrophobic: uncharged and nonpolar compounds that repel from water i.e. oil/fat- Properties:o Water is Cohesive  binding between like moleculeso Adhesive- Binding between unlike molecules o Denser as a solid than a liquid  expands as it changes from a liquid to a solid o Ability to absorb large amounts of energy 10. Reactions- pHo expresses proton concentration in a solution  Pure water = 7 Acids: < 7- a substance that increases H concentration in a solution - add Carbonic acid to bases as a buffer Bases: > 7- a substance that reduces H concentration of a solution - Add bicarbonate to acids as a buffero pH scale change in one unit of pH= 10X change in H concentration - Chemical Reactionso Chemical equilibrium: occurs when the forward and reverse reactions proceed at the same rate and the quantities of reactants and products remains constant o Endothermic reaction: need to