FOR2060 1st Edition Lecture 4 Outline of Last Lecture I. Biological OrganizationII. AutecologyIII. Population EcologyIV. Community EcologyV. Ecosystem Ecology A. What is an ecosystem?B. StructureC. FunctionD. Complexity E. Interaction and InterdependenceF. Temporal Change Outline of Current Lecture VI. Why do Ecosystems Change?A. Ecological SuccessionB. Primary Succession C. Secondary Succession D. Autogenic SuccessionE. Allogenic SuccessionF. Biogenic Succession VII. Understanding an EcosystemVIII.What is Energy?A. Energy B. PhotonC. The SunD. Effect of Aspect IX. Basic PhysicsA. First Law of ThermodynamicsB. Second Law of Thermodynamics X. Ecosystem and Production Ecology A. AutotrophsB. HeterotrophsC. DetritivoresD. Primary ProducerE. Primary Consumer 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.F. Tertiary Consumer G. Pyramid of NumbersH. Pyramid of BiomassI. Energy Flow Pyramid Current LectureVI. Why do Ecosystems change?Ecosystems change for many reasons, including climate change, changes in soil conditions, interactions within the community, and community disturbances. Ecological succession refers tohow an ecosystem develops and changes over time. Primary Succession is succession that startsfrom scratch in an area where plant life has not previously existed. Secondary Succession is succession that is caused by some kind of disturbance. There are different types of secondary succession. Autogenic succession occurs when plant communities drive succession. An example: when a plant enriches the soil, allowing a new plant to establish and grow. Allogenic succession occurs when a force of change is external to the biotic community. Examples include fire, flood, and drought. Biogenic Succession occurs when a living organism becomes a major (and often temporary) driver of successional change. Examples include disease, sudden increasein herbivore pressure, and invasive plants. VII. Understanding an Ecosystem To understand an ecosystem, you must recognize that functional organization is largely matter of energy transfer and storage. You must appreciate the pathways and magnitudes of energy transfer and be able to identify the factors that determine the storage and dynamics of energy within and between ecosystem components. VIII. What is Energy?Energy is defined as a source of power that organisms use for survival, growth, and reproduction. All energy comes from the sun! The energy travels in photons, which are the fundamental unit of solar energy. The photons are released from the sun and travel through space; only a small amount of photons hit the earth and provide us with energy. The angle of the sun’s rays determines the energy available for that point on earth. Aspect refers to the direction that a slope faces. The aspect affects how much energy you will get. On the north south aspect, the south side will get more solar energy. The effect of aspect is not that important around the equator, but it is quite important in the middle latitudes. East versus west aspects are also important. The sun rises in the east and sets in the west. When the sun raises, the earth has not yet had time to warm up so the east aspect gets sunlight but it does not warmup too much. By the time the sun reaches the west aspect, the earth has already warmed, so there tends to be a drying affect on the western sides of mountains.IX. Basic Physics The First Law of Thermodynamics states that energy is neither created nor destroyed but it maybe transferred or transformed. Interactions in ecosystems are basically energy transfers and transformations. The Second Law of Thermodynamics states that in all energy exchanges, the potential energy of the state will always be less than that of the initial state. The excess energy is lost as heat. X. Ecosystem and Production Ecology There are two major groups of organisms, depending on the source of energy. Autotrophs utilize abiotic energy sources, like plants, which are called photoautotrophs. Chemoautotrophs get their energy from breaking chemical bonds. Heterotrophs utilize biotic energy sources, so these are anything that eats something else. These include herbivores, carnivores, omnivores, and detritivores (which eat dead things). There are five trophic levels. Primary producers are always autotrophs and provide the rest of the ecosystem with energy. Next is the primary consumer, which is generally an herbivore. Then you have the secondary consumer, which are carnivores. Then there are tertiary consumers, which are carnivores that eat other carnivores. Lastly are the detritivores, which are the decomposers. The assignment of an organism to a single trophic level is not always easy due to how the diets of species my vary depending on its life history and circumstances. We can see how energy flows through an ecosystem by looking at a pyramid of numbers. There are a large number of primary producers in grassland, and each successive trophic level is smaller. In a forest, the primary producers are fewer and larger. This leads to a smaller base of the pyramid with a larger block of primary consumers. You can also look at a pyramid of biomass, which shows how the energy is transferred and how energy is lost. There is also the energy flow pyramid, which is ALWAYS a pyramid. The boxes refer to the size of the energy in each trophic level and according to the laws of thermodynamics the boxes must get smaller as you go