1 st Semester Final Review Systems Systems are networks of interactions among interdependent components. It is an organized group of related objects or components that form a whole. Systems have boundaries, components, resources flow (input and output), and feedback. Open Systems Systems can be closed, open, or isolated. Open systems contain matter, energy, or information that is exchanged between parts of the system and external sources. Closed System Closed systems exchange energy but not matter (does not naturally occur). Eg. Submarine Ecosphere Bioshpere 2 Water and nitrogen cycles approximate to closed systems Isolated Systems Isolated systems Exchange neither matter nor energy. No such system exists (with the possible exception of the entire cosmos). Feedback Loops Positive Feedback Illustrations Positive Feedback graph Positive Feedback Loop Negative Feedback Illustrations Negative Feedback Graph Negative Feedback Loop Energy For Life Thermodynamics First Law of Thermodynamics Energy is conservedit is neither created nor destroyed, rather it changes from one form to another Eg. Electrical to heat energy Therefore the same amount of the energy that goes into a system, leaves the system. Thermodynamics Second Law of Thermodynamics With each successive energy transfer, less energy is available to do work. The energy is degraded to lower quality forms or It is lost as heat-- dissipates Energy Flow Diagrams Show how nutrients are cycled through the ecosystem, and how much of the energy is lost as heat. Yellow arrows = energy Blue arrows = nutrients Arrow width can vary to represent flow quantity, although this diagram does not illustrate this. Boxes = storages Cellular Respiration Cellular respiration demonstrates the 2 nd Law of Thermodynamics Ecology Biological Pyramids--Productivity 10% Rule Only about 10 % of the energy in one consumer level is represented the next higher level. In other words 90% is lost. Productivity Productivity is one of the most important properties of an ecosystem. There are 2 kinds of productivity: Primary productivity Basis for almost all growth in an ecosystem. Autotrophs (Photosynthesizers) are responsible for the primary productivity in an ecosystem. Secondary productivity The manufacture of biomass (biological material) by organisms that eat plants. Primary Productivity and Ecological Succession What happens to biodiversity during ecological succession? Primary Succession Primary succession begins with a total lack of organisms and bare mineral surfaces (for example a lava field) or water. There is no gross productivity. Secondary Succession Secondary succession occurs when an existing community is disturbed or destroyed (for example by fire, flood, or human activity) but much of the soil and some of the organisms remain. Terrestrial Primary Succession Terrestrial primary succession A pioneer community is a collection of organisms able to colonize bare rock (e.g., lichens). Lichens help break down rock and accumulate debris, helping to form a thin soil layer. The soil layer begins to support small forms of life. Terrestrial Primary Succession Steps to terrestrial primary succession 1.Lichen community replaced by annual plants. 2.Annuals replaced by perennial community. 3.Perennial community replaced by shrubs. 4.Shrubs replaced by shade-intolerant trees. 5.Shade-intolerant trees replaced by shade-tolerant trees. 6.Stable, complex, climax community eventually reached. Terrestrial Primary Succession Climax Community A climax community is a relatively stable, long- lasting community that is the result of succession. The kind of climax community that develops is primarily determined by climate and soil type. Eg. Pacific Northwest old growth forest or a desert Aquatic Primary Succession Aquatic primary succession Except for oceans, most aquatic systems are considered temporary. All aquatic systems receive inputs of soil particles and organic matter from surrounding land. This results in the gradual filling of shallow bodies of water. Roots and stems below water accumulate more material. Establishment of wet soil. Primary Succession Primary succession from a pond to a wet meadow. Carbon Cycle Carbon cycle ***Note the magnitude of the arrows for each diagram in this power point. Phosphorus Cycle Phosphorus cycle Hydrologic Cycle Symbiotic Relationships Symbiosis is a close, long-lasting, physical relationship between two different species. At least one species derives benefit from the interaction. There are five categories of symbiotic relationships: Parasitism +/- Commensalism +/0 Predation +/- (see previous slides for definitions) Herbivory +/- (see previous slides for definitions) Mutualism +/+ Abiotic vs. Biotic Abiotic factors are nonliving things that influence an organism. Organized into several broad categories Energy Nonliving matter Minerals rocks Bodies of water Living space Amount Elevation Topography aspect Ecological processes Climate Temperature Precipitation Biotic Factors Biotic factors are all forms of life with which an organism interacts. Organized into several broad categories Plants that carry on photosynthesis Animals that eat other organisms Bacteria and fungi that cause decay Bacteria, viruses, and other parasitic organisms that cause disease. Species A species refers to all organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspring. A Dalmatian and a Chihuahua can produce live, fertile offspring. True or false? A donkey and a horse can produce live, fertile offspring. True or false? Population and Community A population consists of all the members of a species living in a given area at the same time. (Eg.???) All of the populations of organisms living and interacting in a particular area is a biological community Ecosystem An ecosystem is composed of a biological community and its physical environment. Pacific Northwest ecosystem Arcatas constructed wetland. What are some abiotic and biotic factors from the article? Habitat The habitat of an organism is the space that the organism inhabits, the place where it lives (its address). Niche The niche of an organism is the functional role it has in its surroundings (its profession) Includes all the ways it affects the organisms with which it interacts as well as how it modifies its physical surroundings. Eg. Beaver and Dandelion Food Webs and Trophic Levels Trophic level is an organisms feeding status in an ecosystem. EEg. grass is at the producer level EEg. A mouse that eats the plant is at the primary consumer (organisms that harness the energy from producers) level. Food Webs and Trophic Levels Primary Consumers Eat producers Secondary Consumers Eat primary consumers Tertiary Consumers Eat secondary consumers This picture depicts the trophic levels within a food chain (one branch of a food web) Food Webs and Trophic Levels A food chain is a linked feeding seriesthe sequence of organisms through which energy and materials are transferred from one trophic level to the next. Food webs are complex, interlocking series of individual food chains in an ecosystem. DDepending on which chain within the web is followed, an organism, for example, may be considered a primary consumer or a secondary consumer. Food Webs and Trophic Levels Notice that the arrows point in the direction of the energy flow. It is not based on who gets eaten, rather on who is doing the eating. If an ecosystem is in a steady state equilibrium, then the recently observed behavior of the system will continue into the future Biomes: Major Types of Terrestrial Climax Communities Two primary abiotic factors have major impacts on the kinds of climax communities that develop in any part of the world. Temperature Patterns of precipitation. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world Biodiversity Loss and Extinction Biodiversity is a broad term used to describe the diversity of genes, species, and ecosystems in a region. A number of factors influence diversity: Ecological succession Habitat diversity Complex ecosystems Provide stability Stable ecosystems are more likely to survive change and thus provide more biodiversity over a longer period of time. Measurement of Biodiveristy Simpson Diversity Index D = N(N-1) n(n-1) Where N=total number of organisms n=number of individuals of different species Geographic Isolation Speciation occurs as a result of the isolation of populations. eg. Darwins finches Biodiversity Hotspots (Enger pg. 237) Is there a correlation? # of species to go extinct since 1800 Human population since 1800 E.O. Wilsonthe father of biodiversity estimates that 27,000 species are currently lost each year. Biodiversity Loss and Extinction Organisms more prone to extinction: Organisms in small, restricted areas, such as islands. Environmental changes have large effect. Biodiversity Loss and Extinction Organisms more prone to extinction: Specialized organisms Relying on constancy of a few key factors. Eg. Pandas only eat bamboo Biodiversity Loss and Extinction Organisms more prone to extinction: Organisms at higher trophic levels. Low population sizes and reproductive rates. Eg. Northern spotted owl baby mortality rate is 90%! Biodiversity Loss and Extinction Organisms more prone to extinction: Species with small, dispersed populations Successful breeding is difficult. Endangered Species Act (ESA) In the U.S., the primary action related to the preservation of biodiversity involved the passage of the Endangered Species Act (1973). What Is Being Done to Preserve Biodiversity? The IUCN (International Union for Conservation of Nature) uses the Red List to determine a species statusRed List Scientists look at several factors: Population size Population reduction Numbers of mature individuals Geographic range and degree of fragmentation Quality of habitat Area of occupancy Probability of extinction Politics Non-governmental agencies (NGOs) To Save or Not to Save Things to consider when deciding on priority Keystone specieshave a major effect on ecological functions To Save or Not to Save Things to consider when deciding on priority Indicator speciestied to specific biotic communities To Save or Not to Save Things to consider when deciding on priority Umbrella species require large blocks of undisturbed habitat Species-Based Approach to Conservation A species-based approach Species may be chosen based on the concept of an umbrella species whose requirements are believed to incorporate the needs of other species That is, decisions concerning land management, for example habitat size, distance from other communities and risk from threatening processes are based primarily on one species Advantage: in preserving one species the needs of other species present are automatically met. Protected Areas The IUCN (International Union for the Conservation of Nature) specifies six categories of protected areas: I. Strict nature reserve/wilderness area: protected area managed mainly for science or wilderness protection II. National park: protected area managed mainly for ecosystem protection and recreation III. Natural monument: protected area managed mainly for conservation of specific natural features IV. Habitat/Species Management Area: protected area managed mainly for conservation through management intervention V. Protected Landscape/Seascape: protected area managed mainly for landscape/seascape protection and recreation. VI. Managed Resource Protected Area: protected area managed mainly for the sustainable use of natural ecosystems. Threats to Biodiversity Causes of extinction Primary Succession Primary succession begins with a total lack of organisms and bare mineral surfaces (for example a lava field) or water. There is no gross productivity. Secondary Succession Secondary succession occurs when an existing community is disturbed or destroyed (for example by fire, flood, or human activity) but much of the soil and some of the organisms remain. Terrestrial Primary Succession Terrestrial primary succession A pioneer community is a collection of organisms able to colonize bare rock (e.g., lichens). Lichens help break down rock and accumulate debris, helping to form a thin soil layer. The soil layer begins to support small forms of life. Terrestrial Primary Succession Secondary Terrestrial Succession Secondary succession on land Each step in the process is known as a seral stage, and the sequence of stages is called a sere. Climax Communities Climax communities show certain characteristics when compared with successional communities. Climax communities maintain species diversity for an extended period. They contain multiple specialized ecological niches. They maintain high levels of organism interactions. Climax communities recycle nutrients while maintaining a relatively constant biomass. Aquatic Primary Succession Aquatic primary succession Except for oceans, most aquatic systems are considered temporary. All aquatic systems receive inputs of soil particles and organic matter from surrounding land. This results in the gradual filling of shallow bodies of water. Roots and stems below water accumulate more material. Establishment of wet soil. Primary Succession Primary succession from a pond to a wet meadow. This graph shows how GPP and respiration differ as ecological succession progress. Biological Pyramids There are 3 kinds of biological pyramids. Productivity Biomass Number Biological Pyramids--Productivity Productivity can be expressed in terms of a pyramid because of the 2 nd law of thermodynamics. There is less energy available as you go up the food chain. In other words it takes many oak tree leaves to support one caterpillar, many catepillars to support one bluetit, and many bluetits to support one sparrowhawk. Biological Pyramids--Productivity 10% Rule Only about 10 % of the energy in one consumer level is represented the next higher level. In other words 90% is lost. Productivity Productivity is one of the most important properties of an ecosystem. There are 2 kinds of productivity: Primary productivity Basis for almost all growth in an ecosystem. Autotrophs (Photosynthesizers) are responsible for the primary productivity in an ecosystem. Secondary productivity The manufacture of biomass (biological material) by organisms that eat plants. Productivity Gross productivity is the amount of energy trapped in organic matter during a specified interval at a given trophic level. (Gross means before deduction, for example, gross income which is a persons income before taxes are deducted). Think TOTAL energy Productivity Net productivity is the amount of energy trapped in organic matter during a specified interval at a given trophic level less that lost by the respiration of the organisms at that level Productivity Calculations Net Primary Productivity can be calculated from the following equation: NPP = GPP R Where NPP = net primary productivity GPP = Gross primary productivity R = respiratory loss Productivity Calculations Net Secondary Productivity can be calculated from the following equation: NSP = GSP R Where NSP = net secondary productivity GSP = food eaten fecal loss R = respiratory loss Biomagnification The biomagnification of DDT. Numbers shown are in ppm. The amount of DDT in the bodies of the organisms increases as we go from producers to herbivores to carnivores. Because DDT is persistent it builds up in the trophic levels of the food chain Soil Parts of the Earth Structure of the Earth Plate Tectonics Plate tectonics is the concept that the outer surface of the Earth is made of large plates of crust and outer mantle that are slowly moving over the surface of the liquid outer mantle. Heat from the Earth causes the slow movement. Plates are pulling apart in some areas, and colliding in others due to convection cells. These building processes are counteracted by processes tending to make elevated surfaces lower i.e.erosion. Plate Tectonics Heat from Earths inner and outer cores is transferred through the mantle by a process called mantle convection. The mantle moves the plates along with it as it convects. Diversity Diverse geographic formations lead to ecological diversity. Ecological diversity leads to biological diversity (biodiversity). organisms have adapted (evolved) to live in a certain geographic region. Examples: Artic hare Deep water fish Mountain goats Bison Soil Composition The components of soil. Carbon cycle Nitrogen cycle Soil System Inputs Air Precipitation Organic matter (nutrients) Energy Transformations Changing of one gas to another Weathering Outputs include Air Uptake by plant and movement of matter Transfers material is moved around. Soil FormationAbiotic Factors Chemical weathering Chemical alteration of rock Causes fragmentation or dissolving Examples: Oxidation, slightly acidic rain water Mechanical weathering Forces that reduce the size of rock particles without changing the chemical nature of the rock. Causes fragmentation Examples: include freezing and melting of ice and plants and animals Soil Properties Soil structure refers to the way various soil particles clump together. An ideal soil for agricultural use is loam, which combines the good aeration and drainage properties of large particles with the nutrient retention and water- holding ability of clay particles. Soil Properties Soil texture Soil Properties Soil Organisms Nematodes and earthworms process plant roots and litter. Bacteria and fungi typically decompose organic detritus and recycle nutrients used by plants. Bacteria found in soil (called actinomycetes) gives us the antibiotics streptomycin and tetracycline. Insects and algae A single gram of soil can contain hundreds of millions of unicellular organisms. Soil Profile Major soil types Make sure you label the horizon pictures on your notes with the correct ecosystem Abuses of Soil There are 3 main ways that soil is degraded. Erosion Toxification Salinization Water Erosion Water erosion caused by exposed soil when native plants are removed from the site. Examples: deforestation, building sites, clearing for crops. Wind Erosion Wind erosion may not be as evident as water erosion, but is still serious. It is most common in dry, treeless areas. Great Plains of North America have had four serious bouts of wind erosion since European settlement in the 1800s. Abuse--Toxification Toxification is caused when modern agriculture sprays toxic chemicals to kill or drive away pests (insects or weeds). Examples are pesticides and herbicides have doubled the crop yield. Results in: Killing nontarget species Creating new pests or organisms Pesticide resistance Pollution of waterways Abuse--Salinization Salinization is caused by too much irrigation which leads to waterlogged soil. Salinization results in mineral salts accumulating in the soil (due to the fact that irrigation water contains some salt). This results in leaving behind a crusty layer of salt Consequence: Lethal to plants (think osmosis) Soil Conservation Practices Soil Quality Management Components: Manage pests and nutrients efficiently. Prevents toxification Prevent soil compaction. Plants dont grow in compacted soil. Diversify cropping systems. Keeps nutrients from being drawn out of the soil. Soil Conservation Practices Ways to prevent salinization: Dont over water. Use technology like drip irrigation or downward-facing sprinklers. Soil Conservation Practices Alternative Cultivation Contour farming is tilling at right angles to the slope of the land. Each ridge acts as a small dam. Useful on gentle slopes. One of the simplest methods for preventing soil erosion. Strip farming is the practice of alternating strips of closely sown crops to slow water flow, and increase water absorption. Soil Conservation Practices Terracing is the practice of constructing level areas at right angles to the slope to retain water. Good for very steep land. Undernourishment Due to poverty Undernourishment In 1960 nearly 60% of the people living in developing countries were considered chronically undernourished. Today, despite the fact that their population has doubled over the past 40 years this number has fallen to less than 15 %. How is this possible? Advantage of fertilizers/pesticides What does that say about a change in carrying capacity? Malnourishment anemia Overnourishment