Transcript Slide 1
Environmental Science PS 6.3-6.6 Standards B-6.3 Illustrate the processes of succession in an ecosystem B-6.4 Exemplify the role of organisms in the geochemical cycles (including the cycles of carbon, nitrogen, and water). B-6.5 Explain how ecosystems maintain themselves through naturally occurring processes (including maintaining the quality of the atmosphere, generating soils, controlling the hydrologic cycle, disposing of wastes, and recycling nutrients). B-6.6 Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and processes of Earth. Vocabulary Agriculture Technology Alternative Energy Carbon Cycle Carrying Capacity Consumption of Resources Denitrification Deposition Ecological Succession Geochemical Cycles Geosphere Greenhouse Effect Hydrologic Cycle Industrial Technology Nitrogen Cycle oNitrogen Fixation oNon-Renewable Resources oOzone Layer oPioneer Species oPopulation Growth oPrimary Succession oRenewable Resources oSecondary Succession oSink oSoil Erosion oSustainability oTechnology oWater Cycle Section 1: Succession in Ecosystems 1) Succession is a series of changes in an ecosystem when one community is replaced by another community because of changes in biotic and abiotic factors. a) Succession occurs in all ecosystems. 2. Primary Succession a) Takes place in an area that has not been inhabited before by plants and animals i. Examples: rock surfaces formed by lava, rocks scraped clean by glaciers, and city streets Primary Succession Begins with organisms that can grow without soil b) Lichens and some mosses break down rocks into smaller species. These are examples of pioneer species. ii. When there is enough soil and nutrients small plants start to grow and break the rock down further which makes more soil. iii. Seeds from other plants and small trees grow. iv. As species grow and die their decomposed bodies add nutrients to the soil and even larger plants are able to populate the area. i. Lichen http://frankwinters.wordpress.com/2007/01/09/lettuce-lichen-and-henry-david-thoreau/ http://www.thbfarm.com/Gardens_for_Nature.html http://commons.wikimedia.org/wiki/File:Lichen_DSC00612.JPG Primary Succession 3) Secondary Succession a) Begins in an area where there used to be an community and has well-formed soil b) Examples: abandoned farmland, empty lots, clear-cut forest areas, areas burned by forest fires. Secondary Succession c) When something like a hurricane, wildfire, or human activities destroys a community secondary succession takes place. i. It is like primary succession in the later stages after soil has formed. ii. When the disturbance is over, the ecosystem restores the original condition of the community. Secondary Succession d) Occurs faster than primary succession because soil is already present i. When disturbances happen often or are intense, the area will mostly have the species that are present in the early stages ii. When disturbances are moderate, the area will have habitats at different stages. Section 2 – Biogeochemical Cycles Biogeochemical Cycles Biogeochemical cycles are the movement of forms of matter through the living and nonliving parts of an ecosystem. a) Matter changes forms but is never created or destroyed. b) In biological systems matter is used over and over again in different forms. 1) 2) Carbon Cycle a) Carbon is the major part of biochemical compounds. b) Carbon is the major part of living things (proteins, carbohydrates, lipids, nucleic acids). Carbon Cycle c) Carbon is found in the atmosphere and in many minerals, rocks, and fossil fuels (gas, petroleum, coal). carbon dioxide in air combustion respiration photosynthesis respiration decomposition of organisms fossil fuels photosynthesis carbon dioxide dissolved in water Anything that stores carbon is called a sink. i. Oceans are the Earth's largest carbon sinks ii. Plants and soil are also carbon sinks. d) Carbon Cycle e) Ways Carbon is Recycled Photosynthesis 1) Plants and other photosynthetic organisms use carbon dioxide from the atmosphere and turn it into simple sugars. ii. Respiration 1) Organisms (like us!) break down glucose in our bodies and carbon dioxide (CO2) is released into the atmosphere when we breath out. i. Carbon Cycle Decomposition 1) When organisms die, decomposers break the bodies down into carbon compounds that enrich the soil and are eventually released into the atmosphere as CO2. iv. Conversion of biochemical compounds 1) Organisms store carbon as carbohydrates, proteins, lipids (fats), and nucleic acids in their bodies. iii. Carbon Cycle v. Other ways carbon may be released: 1) Combustion: Burning of wood or fossil fuels – this releases Co2 into the atmosphere. 2) Weathering of rocks: Bones and shells fall to the bottom of oceans or lakes and become a part of the rocks, such as calcium carbonate. When these sedimentary rocks weather, carbon is released into the ocean and eventually into the atmosphere. 3) Nitrogen Cycle a) Nitrogen is needed to build proteins in organisms and is found in materials that compose soil and aquatic sediments. b) Elemental nitrogen (N2) is found in the atmosphere Nitrogen Cycle Ways organisms recycle nitrogen: i. Nitrogen-Fixation 1) Nitrogen-fixing bacteria which live in the soil, roots of plants, and aquatic ecosystems, convert nitrogen from the air into forms that plants can use ii. Intake of nitrogen into organisms 1) Plants take in nitrogen through their roots in the form of ammonia and nitrate. This is how nitrogen enters the food chain. c. Nitrogen Fixation Bacteria live in these little nodules http://www.jic.ac.uk/corporate/about/publications/advances/issue_6.html A bunch of bacteria in a root nodule http://io.uwinnipeg.ca/~simmons/16cm05/1116/16monera.htm Nitrogen Cycle iii. Decomposition 1) When an organism dies or from animal waste, decomposers return nitrogen to the soil. nitrogen in in nitrogen atmosphere atmosphere animals animals plant plant nitrates nitrates nitrogen-fixing nitrogen-fixing bacteria in in decomposers nitrifying bacteria decomposers nitrifying roots bacteria roots bacteria ammonification ammonification nitrites nitrites nitrogen-fixing nitrogen-fixing ammonium bacteria in soil ammonium bacteria in soil nitrifying nitrifying denitrifying denitrifying bacteria bacteria bacteria bacteria Nitrogen Cycle iv. Denitrification 1) Denitrifying bacteria break down nitrogen compounds in the soil and release it into the atmosphere. 4. Water Cycle (Hydrologic Cycle) water is necessary for all life processes in living things. b) Water is in the atmosphere, surface of the earth, underground, and in organisms. c) The water cycle is driven by the heat from the sun because it causes evaporation a) Water Cycle (Hydrologic Cycle) precipitation condensation transpiration lake groundwater surface runoff evaporation water storage in ocean Water Cycle (Hydrologic Cycle) d) i. Ways organisms recycle water: Intake of water 1) Organisms use water to perform life functions ii. Transpiration 1) The release of water back into the atmosphere by plants iii. Respiration 1) Organisms produce water as a by-product of metabolizing food iv. Elimination 1) Organisms need water to help with eliminating wastes Section 3 – Ecosystem Care 1) Naturally occurring processes on Earth are needed to help ecosystems to maintain the materials that organisms need. 2) The earth is made of 4 parts: biosphere (inhabited by life) b) Atmosphere c) Hydrosphere d) Geosphere a) i. These systems must interact efficiently for an ecosystem to maintain itself 3.) Maintaining the Quality of the Atmosphere Oxygen and carbon dioxide are cycled through the atmosphere a) i. b) Plants use carbon dioxide in the air to make their food and give off oxygen as a waste product Animals use the oxygen for respiration and release carbon dioxide as a waste product. oxygen photosynthesis respiration carbon dioxide Maintaining the quality of the atmosphere d) The oxygen produced during photosynthesis is also used to make up the ozone layer which protects the biosphere from the Sun’s radiation. e) Water also maintains the atmosphere i. When water vapor condenses, dust and other particles are removed from the atmosphere and falls with the rain or snow. (The air gets cleaned!) 4. Greenhouse Effect Carbon dioxide, oxygen, and water vapor trap heat energy to help maintain Earth’s temperature b) Greenhouse gases do not let heart to pass through them very well, so heat that the Earth releases stays trapped c) The amount of carbon dioxide depends on how much photosynthetic organisms are absorbing it. a) Greenhouse Effect Amount of CO2 in the atmosphere Greenho use effect Average Global Temperatu re Plant cover on earth Rate of photosynthe sis Amount of CO2 absorbed by plants Amount of CO2 in the atmosphere Higher Increases Increases Increases Increases Increases Decreases Lower Decreases Decreases Decreases Decreases Decreases Increases 5) Global Warming a) Global warming is the trend of increasing global temperatures b) Scientists believe the increased temperatures are from greenhouse gases given off by industry and automobiles c) Global warming is a hotly debated topic - some scientists believe global warming is a result of climate patterns d) There is concern over how these temperature changes will affect ecosystems and especially biodiversity 6) Air Pollution a) Most air pollution comes from the burning of fossil fuels such as gas and oil. i. Smog is air pollution that results from the interaction of sunlight and pollutants including particulates (tiny particles of dust, metal, and fuel). ii. Acid rain is a type of precipitation produced when pollutants cause the rain's pH to drop (makes it more acidic). 1) Acid rain makes lakes and streams more acidic, threatening water supply and the habitats of many species. It also damages plants. 7) Generating Soils Soil is part of the geosphere – they are always being formed and eroded b) Soil is made of: minerals, organic matter, water, and air c) Soil is formed from by weathering of inorganic materials by wind, water, and ice and the decoying of organic materials a) Generating Soil Wind, water, and ice cause soil erosion and deposition which moves soil from one place to another Plants help keep the process of soil production to be consistent with the process of soil erosion d) e) I. f) The plants roots hold the dirt in place, and also block wind from blowing the dirt) Soil is needed for succession to take place. 8) Controlling the Hydrologic Cycle This cycle is maintained by the sun and weather b) It purifies water: a) Evaporated water has no impurities ii. Water that seeps through soil and rock is filtered of impurities iii. As water flow slows, heavier particles settle out which leaves purified water to travel to the ocean i. c) Water Pollution i. Runoff from farms and cities may contain toxic chemicals and trash that can disrupt the stability of freshwater lakes and streams. 1) Ex. fertilizers from farms can cause algae overgrowth which lowers the amount of oxygen for the fish 2) An indicator species gives a sign that an ecosystem is being affected such as frogs with deformities from coming into contact with toxic chemicals 3) Biomagnification takes place when a pollutant moves up the food chain as predators eat prey. The species at the top are affected the most. 9) Disposing of Waste & Recycling Nutrients Waste materials from organisms are decomposed by bacteria or other organisms b) Nutrients cycle from organisms to the environment and back by the geochemical cycles a) 10. Human Roles in Geochemical Cycles a) People depend on the resources and cycles on earth to provide clean water, clean air, and soil that can support crops. b) Human activities such as population growth, technology, and using resources affect the cycles and processes on earth. Section 4 – Population Growth 1. Carrying Capacity Energy, water, oxygen, and nutrients determine the carrying capacity of humans on earth. 2) In order for humans to have sustainability, there needs to be a balance between Earth’s resources and carrying capacity, the needs of humans, and the needs of other species on earth 1) 2. Population Growth Population growth has grown exponentially b) The population rate naturally slows as the Earth nears carrying capacity as the death rate increases and the birth rate decreases due to: a) Food and water shortages ii. Pollution iii. Disease i. http://www.treehugger.com/files/2009/05/world-population -growth-good-news-asia-pacific-rates-starting-to-decline.php myafrica.wordpress.com http://serc.carleton.edu/quantskills/methods /quantlit/popgrowth.html 3. Increasing Population Problems Clean water runs low if water is being used up faster than it can be purified b) More waste is produced than can be managed. Can also be expensive to deal with c) Fertile soil for agriculture is lost when land is cleared a) i. Worldwide demand for land has led to deforestation Increasing Population Problems d) Areas of the world with very high populations have low amounts of fertile soil, clean water, and available land. This affects the water, nitrogen, and carbon cycles as well as soil regeneration. http://www.bnvillage.co.uk/news-politics-village/101777-does-obama-administration-want-reduceafrica-s-population.html Section 5 - Human Activity on Earth 1. Technology Technology applies scientific knowledge to find solutions and develop products that meet the needs of humans. Technology has helped humans, but has also caused pollution. b. Now humans depend on technology to provide cleaner ways to deal with waste and to clean up pollution. c. Technology agriculture and industry can either have a positive or negative impact on Earth. a. 2. Agricultural Technology Technology has improved the ability to grow crops to sustain a growing world population. b) Sustainable practices can conserve fertile soil and reduce erosion a) Agricultural Technology Farm machinery use nonrenewable resources and can contribute to erosion and air pollution. d) Fertilizers, pesticides, fungicides, and livestock waste can change the soil and have both positive or negative effects on the different cycles we are learning about. c) 3) Industrial Technology Industrial technology has helped to develop communication, transportation, and industry. b) Certain chemicals like CFCs can deplete the ozone layer. The ozone layer helps protect the earth form ultraviolet waves. c) Getting rid of old technological equipment has become a problem. a) CFCs were once used in air conditioners Industrial Technology Burning fossil fuels is needed for industry and transportation and helps sustain the growing human population; however: d) i. ii. It increases greenhouse gases (carbon dioxide) which many scientists believe increase global temperatures It produces acid rain. 4) Alternative Technology Using natural renewable resources (wind, water, geothermal, or solar energy) decreases the burning of fossil fuels b) Nuclear energy is another energy source. A big problem with nuclear energy is where to store the waste produced. a) 5) Consumption of Resources As the population increases and technology expands, the need for resources increases. There is only a limited supply. b) Resources such as food, clean water, and timber are renewable. a) i. ii. Renewable resources have factors that limit their production Ex: growing grain requires land, fertile soil, and clean water Consumption of Resources Nonrenewable resources cannot be produced at the rate they are consumed c) i. ii. d) Minerals and metals are important for industry but are decreasing in availability Minerals are formed so slowly that they take to long to replace Sustainable use of resources can be accomplished by not using them as much, reusing products, and recycling waste.