ENVS 101 1st Edition Lecture 24 Outline of Last Lecture I. Why Climates ChangeOutline of Current Lecture II. Energy and Matter in EcosystemsIII. Global Cycles of LifeIV. Biomes: Earth’s Major EcosystemsCurrent LectureEcosystem: A community of interconnected organisms and abiotic (non-living) environmental factors. In order to support life, a system must have: 1. Flow of Energy: Energy is used to produce organic matter, and do work (move bodies and chemicals in bodies).2. Continual recycling of chemical elements:Biomass: The total amount of organic material. Organic compounds are used to grow biomass, as fuel in metabolism and respiration releasing heat, as well as to store energy for future use.Autotrophs: derive energy and create biomass from the inorganic (abiotic) system by: Photosynthesis and other chemical pathways.Heterotrophs: build body mass by eating other organismsA food chain is the pathway by which energy moves through an ecosystem. Interconnected foodchains are a food web.Food-energy (trophic) levels together form a tropic pyramid. The amounts of energy and biomass decrease from bottom to top. As we move up the pyramid 80-90% of energy is lost at each step upwards. Energy is lost by respiration (activity) where it is lost as heat, and also when it is not eaten/digested.Decomposers: Recycle excreted waste products as well as dead bodies of other organisms. Decomposers are mainly bacteria and fungi. They are also critical to keeping nutrients and the ecosystem. These 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.Note: energy flows one way in a food web, while matter is generally cycled.There are only 24 chemical elements that are essential nutrients. Elements under this category are known to be required for life. Micronutrients are elements that are required in small amounts by all life or in moderate amount by some forms of life. Macronutrients are elements that are required by larger amounts by all life. When a nutrient is not adequately available for biologic growth it is a limiting factor. Concentration factor is a ratio that describes how much an element is increased in an organism compared to its environment.Mechanisms of Bio concentration: Bioaccumulation is a process in which a substance is taken inwithout being excreted at a comparable rate, it will become more concentrated as the organismages.On the other hand, Bio magnification is a process in which through food chain concentration, the substance is passed from consumer to consumer up to the next trophic level. High order carnivores end up with toxicity issues much more often than producers or simply the animals that are found below high order carnivores on the food chain.A biogeochemical cycle is the complete pathway that a chemical element follows through the Earth system. Open systems that maintain a mass balance since the Earth system is closed. Crucial aspects include: Processes that control the flux, residence time, (reservoir size/flux rate)The carbon cycle is the building block of life, existing in several gaseous forms. Carbon enters the atmosphere through respiration, fires, volcanoes, decay, and ocean diffusion.The nitrogen cycle: Nitrogen gas is unreactive, but it is a necessary component of all proteins. Nitrogen fixation brings nitrogen into the biosphere, 90% of the time by way of bacteria. With nitrogen fixation, nitrogen is able to travel fro the atmosphere into the soil of the Earth. The bacteria that allow for nitrogen fixation also live in the water systems of the world, because not all living things on Earth are found on land.The phosphorous cycle: Plays two important roles in the biosphere. As sugar, phosphate forms the helical framework of DNA. It also facilitates all of life’s energy transactions. This cycle occurs in its oxidized state as phosphate, forming minerals that are found in soils and water. Soil is a link between the geosphere, hydrosphere, atmosphere and the biosphere. It is composed of fragments of rocks and minerals. Humus is partially decayed organic matter. Small living organisms can be present, including worms, mites, bacteria, and fungi.Soil horizons and the soil profile: Accumulation of decaying organic matter, dark humus-rich topsoil, Zone of leaching, Maximum accumulation of clay minerals, Weathered parent rock. Nitrogen and phosphorus are key elements that are used as fertilizers to enhance