Transcript Chapter 3
Chapter 3:Ecosystems & Energy Ecology The branch of biology that deals with the interactions between organisms and the relationship between organisms and the environment. The environment is broken down into two parts: Biotic factors- The living organisms Abiotic factors- The nonliving (physical) factors. A Species group of organisms capable of producing more members of the same organism.. Homo sapiens with Homo sapiens Not Homo sapiens with Homo habilus Population Includes all the members of a species found in a given area. Ex: waterlillies in a pond Ex: The chickadees in a woodlot Population Community Includes all the populations in a given area. Ex: all plants, animals, and microorganisms make up a pond community Community Ecosystem Includes all the members of the community plus the physical environment in which they live in. Ecosystem Is the structural and functional unit studied in Ecology. Ecosystem Biosphere The portion of the earth in which life exists. The biosphere is composed of: Atmosphere- gaseous envelope Hydrosphere- Water (All forms) Lithosphere- Soil and rock Energy- Is the ability to do work. Usually expressed as kilocalories (kcal) or kilojoules (kJ). Two general types of energy- Potential and Kinetic Potential=Stored energy Kinetic= Energy of motion T Potential Energy: Stored energy. Kinetic Energy: The energy of motion. Thermodynamics: The study of energy & its transformations. 1st Law of Thermodynamics: energy cannot be created nor destroyed, but it can be transformed. 2nd Law of Thermodynamics: when energy is converted some usable energy is degraded into a less usable form (heat). Therefore, the amount of usable energy in the universe decreases over time. Forms of Energy Chemical Energy- Stored in chemical bonds. Solar (radiant) Energy- From the sun! Heat Energy- thermal energy that flows from an object with a high temp. (heat source) to an object with a lower temp. (heat sink). Mechanical Energy- Energy in the movement of matter. Nuclear Energy- energy found within atomic nuclei. Electrical Energy- energy that flows as charged particles. Photosynthesis The most common type of autotrophic nutrition In this process, organisms use energy from sunlight, carbon dioxide, and water to make its own food Autotroph An organism capable of making their own food Formula for Photosynthesis 6CO2 + 12H2O + radiant energy C6H12O6 + 6H2O + 6O2 Formula for Respiration C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O + work energy Chemosynthetic Bacteria Discovered in 1977 by submersible Alvin. Found at great depths, at high temperatures (392 F), and near large sources of Hydrogen sulfide. The bacteria take in H2S and O2 and produce water and energy for life. Sunlight NOT required! (II) Energy Flow Relationships For an ecosystem to be selfsustaining, there must be a flow of energy between organisms. The pathway of energy flow in an ecosystem are represented by food chains and food webs. There are three basic classes of organisms in a food web: 1)Producers 2)Consumers a) Primary consumers b)Secondary consumers 3)Decomposers Producers- include green plants and other photosynthetic organisms that synthesize the organic nutrients that supply energy to other members in the community. Consumers- include all heterotrophic organisms. Organisms that feed on green plants are primary consumers, or herbivores. Secondary consumers, or carnivores, feed on other consumers. Decomposers – are the organisms (saprophytes) that break down wastes and dead organisms so that chemical materials are returned to the environment for use by other living organisms. (A) Food Chains Green plants and algae convert radiant energy from sunlight into food. A food chain involves the transfer of energy from green plants through a series of organisms with repeated stages of eating and being eaten. (B) Food Webs In a natural community, most organisms eat more than one species and may be eaten, in turn, by more than one species. Thus, the various food chains in a community are interconnected forming a food web. (C) Pyramid of Energy The greatest amount of energy in a community is present in the organisms that make up the producer level. Only a small portion of this energy is passed on to primary consumers, and only a smaller portion is passed on to secondary consumers. A pyramid of energy can be used to illustrate the loss of usable energy at each Number (Population) Pyramid Biomass Pyramid Energy Pyramid Net Primary Prod. =Gross Prim. Prod. – Plant Respiration (NPP) = GPP (rate) – P.R. Humans compete with other species for energy. Our planet cannot handle human overpopulation.