CES 210 1st Edition Lecture 5Environmental Science Elements of lifeMatter: has mas and takes up space, is neither created nor destroyed but recycled, and can be transformed from one form to anotherElements: substances that cannot be broken down into simpler forms by ordinary chemical reactions- There are 122 elements but only four make up 96% of the mass of living organisms; those four are oxygen, carbon, hydrogen, and nitrogenAll elements are composed of atomsAtoms: smallest particles exhibiting characteristics of the element- Are composed of protons (+) neutrons and electors (-)- Protons and neutrons are in the nucleus while the electrons orbit the nucleusAtomic Number: number of protonsIsotope: forms of an element differing in atomic mass due to the fact that the isotopes have different number of neutrons Chemical BondsCompound: substances composed of different kinds of atomsMolecule: two or more atoms joined togetherChemical Bond: forces of chemical energy holding atoms together in molecules- Ionic: atoms with opposite charges form a bond ex: Na+ and Cl-- Covalent: atoms share electrons (not always equally) ex: oxygen attracts the electrons for than the hydrogen does so the hydrogen’s have a slight positive charge and the oxygen’s have a slight negative chargeCommon Molecules: H2, O2, N2, HCl, H2O, CO2, SO2, NO2, CH4Oxidation and ReductionOxidized: when an atom gives up one or more electronsReduced: when an atom gains electrons- These are both an important part on how organisms gain energy from food- Forming bonds uses energy and breaking bonds releases energyIons, Acids, BasesIons: atoms that have a positive or negative charge because they have more/less electrons and protons- Cations: has a positive charge- Anions: has a negative chargeAcids: substances that release hydrogen ions in waterBases: substances that readily bond with hydrogen ions- pH scale: 0 to 7 is acidic / 7 is neutral / 8 to 14 is basicOrganic CompoundsOrganic Compounds: material making up biomolecules, which in turn make up living things- All organic compounds contain carbonFour Major categories of organic compounds- Lipids- Carbohydrates- Proteins- Nucleic AcidsCellsCells: minute compartments in living organism-carry out processes of life- Surrounded by lipid membrane controlling flow of materials in and out of a cell- Interior may be sub-divided into organelles and sub-cellular particlesEnzymes: molecular catalysts regulating chemical reactions; these are usually proteinsMetabolism: multitude of enzymatic reactions performed by an organismEnergyEnergy: ability to do work- Kinetic: energy in moving objects- Potential: stored energy- Chemical: stored in food or fossil fuelsHeat: energy that can be transferred between objects of different temperatures. When a substance absorbs heat, the motion of its molecules increases and it may change state (ex: liquid becomes gas). Evaporation and condensation distribute heat around the globe.Thermodynamics- Energy must be supplied to keep biological processes running, because as it flows through the various biological processes, it becomes dissipatedFirst Law of Thermodynamics: energy is neither created nor destroyed (it is conserved)Second Law of Thermodynamics: with each successive energy transfer, less usable energy available to perform work- Entropy: (disorder) increasesEnergy for LifeMost organisms depend on the sun for the energy needed to carry out life processChemosynthesis: when an organism gets their energy from inorganic compounds that bubble up from vents in the sea floor or from hot springs- These organisms represent 1/3 of all the biomass on the planet- The methane generated by these undersea communities could be a source of natural gasAll of solar radiation reaching the earths surface is about 10% ultraviolet, 45% is visible, and 45% infrared- Most of this energy is absorbed by land or water or reflected back into space- Only about 1-2% of the sunlight falling on the planet is captured for photosynthesisEnergy from the SunSolar energy is essential for two reasons- Warmth: most organisms can exist only in a relatively narrow temperature rangePhotosynthesis: radiant energy is transformed into high quality chemical energy in the bonds of organic molecules- Most life of earth depends on photosynthesisPhotosynthesis in detail:- Occurs in organelles within cells called chloroplasts- Water and carbon dioxide in the presence of sunlight and chlorophyll turn into glucose and oxygen- Glucose is important because it is a primary source for all metabolic processes. The energy derived from it can be used to make proteins that aid in cellular movement or transportation of ions across membranesCellular RespirationCellular Respiration: the process of releasing energy by splitting carbon and hydrogen atoms from sugar and recombining them with oxygen to produce carbon dioxide and water- This is how animals get all their energy and the reason that you need to breathe is to supply this pathway to oxygenFrom Species to EcosystemsEcology: the scientific study of relationships between organisms and their environmentSpecies: all organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspringPopulation: All members of a species living given area at the same timeBiological Community: all of the populations living and interacting in a particular areaEcosystems: biological community and its physical environment- The physical environment includes non-living factors such as climate, water, minerals, and sunlight- It’s difficult to define the boundaries of an ecosystem. Most ecosystems are open in that they exchange materials and organism with other ecosystemsFood Chains and Food WebsProducers: any plant that undergoes photosynthesisProductivity: the amount of biomass produced given area during a given period of time- Photosynthesis is described as primary productivity because it is the basis for all other growth in an ecosystem- Secondary productivity: manufacture of biomass by organisms that eat plantsFood Chain: linked feeding seriesFood Web: interconnected food chains as most consumers have multiple food sourcesTrophic Level: an organism feeding status a web. Plants are the producer level while animals are consumers. Animals that eat plants are primarily consumers (herbivores) while animals that eat other animals are secondary and tertiary consumers (carnivores and omnivores). The organisms that recycle dead