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Today’s Plan: 5/4/2010 Bellwork: Housekeeping/Test corrections (10 mins) AP Lab 12-DO Ecology notes Today’s Plan: 5/5/2010 Bellwork: Discuss what we’re accomplishing in the lab (10 mins) Finish DO Lab Data collection (40 mins) Notes (the rest of class) Today’s Plan: 5/6/2010 Bellwork: Finish AP Lab 12 Data collection (20 mins) Finish AP Lab 12 questions and Test corrections (30 mins) Continue with notes (the rest of class) Today’s Plan: 5/7/2010 Bellwork: Work on the “Can we feed the world’s population?” sheet (30 mins) Notes (the rest of class) Today’s Plan: 5/10/2010 China Video (60 mins) Finish misc. work (the rest of class) Today’s Plan: 5/11/2010 Finish Ecology Notes (30 mins) Entry document for Final project (15 mins) Class K/NTK list (15 mins) Grouping and norm establishment (the rest of class) Today’s Plan: 5/12/2010 Bellwork: Q&A (10 mins) Ecology test (the rest of class) If you finish early, work on your project! 5/13-5/19/2010 Work with your group on your final project I’ll put out a workshop sign up for your NTKs each day. The last 30 mins, I’ll do the workshops you ask for. 5/20-21 Prepare for your presentations (5 mins) Group project presentations (the rest of class) Ecology This is the study of the distribution, abundance, and interactions of organisms within their environments. Levels of ecology: Organism Population Community Ecosystem Biosphere Figure 50-1 Organismal ecology Population ecology How and why does population size change over time? How do individuals interact with each other and their physical environment? Each female salmon produces thousands of eggs. Only a few will survive to adulthood. On average, only two will return to the stream of their birth to breed Salmon migrate from saltwater to freshwater environments to breed Community ecology Ecosystem ecology How do species interact, and what are the consequences? Salmon are prey as well as predators How do energy and nutrients cycle through the environment? Salmon die and then decompose, releasing nutrients that are used by bacteria, archaea, plants, protists, young salmon, and other organisms Population Ecology Demography-the study of poulations over time, including categories into which the organism falls For individuals in populations: Life expectancy/Life tables Immigration/emigration For whole populations: Density=# individuals/area Dispersion=where you find the individuals in that area Age Structure=Bar graph showing ages and genders of individuals in the population Reproductive rate, r (growth rate)=births-deaths/N N=population size Survivorship curve (3 types) Biotic potential=maximum growth possible for the population under ideal conditions (includes things like reproductive age, clutch size, frequency of reproduction, survival rate of offspring) Figure 50-30a Distribution of cattle is limited by distribution of tsetse flies. Distribution of tsetse fly (red) The two distributions have little overlap (purple) Distribution of cattle (blue) Figure 52-1-Table 52-1 Figure 52-15 Developed country (Sweden) Developing country (Honduras) 2050 projections 2000 data 2050 projections 2000 data Figure 52-2a Three general types of survivorship curves Limiting factors Limiting factors are elements of an ecosystem that are in short supply and therefore set limits on population size Carrying Capacity (K)-maximum number of individuals that can occupy an ecosystem Density-dependent limiting factors-factors whose limiting effects increase as population density increases (ex: disease, famine, etc). Some cause an increase in competition. Density-independent limiting factors-factors whose limiting effects are not tied to population density (ex: natural disasters, climate, etc) Growth models Exponential model-also known as a J curve. Assumes that populations can grow without limit Logistic model-also known as an S curve. Assumes that populations know what K is, and will act accordingly This changes the reproductive rate equation: Change N/Change t=rN(K-N/K) Notice, K is taken into consideration here Reality-models are only as good as their assumptions, which means that the graph of real population growth is slightly different. Figure 52-7a Density dependence: Growth rate slows at high density. Carrying capacity Later growth falls to zero Early growth is rapid Growth begins to slow Growth and Life History These growth models are associated with 2 kinds of life-strategies for organisms: r-selected species=these exhibit rapid, exponential growth. These are often called opportunitstic species because they quickly invade an area, reproduce and die. Offspring mature quickly and are small. (ex: grasses, insects) K-selected species=these are species whose populations are relatively stable, usually around K. They produce a small number os offspring that are large and require lots of care. They reproduce repeatedly (ex: humans) Human Population growth Human population worldwide is reaching 9 billion. It was just 3 billion 100 years ago. Why the rapid rise? Increases in food supply and travel-humans have domesticated, bred, and fine-tuned agriculture (from hunter-gatherer to farmer) Reduction in disease-advances in medicine, like vaccines, antibiotics, etc have dropped the death rate and increased the successful birth rate Reduction in wastes-sewage systems and water treatment have reduced health hazards Expansion of habitat-better housing, clothing, etc have made it easier to live in more places Figure 52-16-Table 52-2 Figure 52-17 Low Population cycles: Predator/Prey Predator/prey describes a relationship between a hunter and an individual that is eaten. In general, changes in the prey population cause similar changes in the predator population since the predator is dependent on the prey. Just keep in mind, the prey are usually predators of the producers, so their population changes are often due to seasonal changes in their prey population. Figure 52-12 The hare-lynx populations cycle every 11 years, on average; the size of the lynx population lags behind that of the hares Hare Lynx Community Ecology Habitat-the area that an organism inhabits within an ecosystem Niche-the role of the organism within the environment1 species per niche Gause’s principle of competitive exclusion=when 2 species try to occupy the same niche, there will be competition until one species leaves or dies Resource partitioning=some species can coexist even though they appear to be competing for the same resources. They are occupying slightly different niches by using the resources in different ways. Character displacement (niche shift)=as a result of resource partitioning, certain characteristics allow organisms to obtain their partitioned resources more successfully Realized niche=This is the niche that the organism occupies b/c of resource partitioning. If there were no competitors, they would otherwise occupy their fundamental niche, but because of niche overlap, they must adjust Figure 53-2 Consumptive competition These trees are competing for water and nutrients. Chemical competition Few plants are growing under these Salvia shrubs. Preemptive competition Space preempted by these barnacles is unavailable to competitors. Territorial competition Grizzly bears drive off black bears. Overgrowth competition The large fern has overgrown other individuals and is shading them. Encounter competition Spotted hyenas and vultures fight over a kill. Figure 53-4a Competitive exclusion in two species of Paramecium Paramecium aurelia Paramecium caudatum Figure 53-4b Competitive exclusion occurs when competition is asymmetric … Asymmetric competition Higher fitness Lower fitness Symmetric competition Same fitness Figure 53-4c … and niches overlap completely. Species 1: Strong competitor Species 2: Weak competitor, driven to extinction Figure 53-4d When competition is asymmetric and niches do not overlap completely, weaker competitors use nonoverlapping resources. Species 1 Species 2 (strong competitor) (weak competitor) Fundamental niche Realized niche Figure 53-3 One species eats seeds of a certain size range. Partial niche overlap: competition for seeds of intermediate size Species 2 Species 1 Trophic Relationships These are the feeding relationships in an ecosystem. Recall from biology that energy transfer between trophic levels is inefficient-only 10% of the energy is transferred, which affects the amount of biomass and the numbers of individuals at each trophic level. This also means that food chains are rarely more than 5 trophic levels. Food chain: primary producerprimary consumersecondary consumertertiary consumerdetritovores (decomposers) Food webs are overlapping food chains in an ecosystem. Recall the following terms: carnivore, herbivore, omnivore Figure 54-1 External energy source, usually solar energy but also chemical energy Primary producers (autotrophs) Organisms that can synthesize their own food Abiotic environment The soil, climate, atmosphere, and the particulate matter and solutes in water Consumers Organisms that eat other living organisms Decomposer Organisms that feed on dead organisms or their waste products Figure 54-5 Trophic level Feeding strategy 5 Quaternary consumer Decomposer food chain Grazing food chain Cooper’s hawk 4 3 2 1 Tertiary consumer Robin Cooper’s hawk Earthworm Robin Bacteria, archaea Cricket Secondary consumer Primary decomposer or consumer Primary producer Dead maple leaves Maple tree leaves Figure 54-6 Cooper’s hawk Robin Fox Alligator lizard Arrows show direction of energy flow: from organism consumed to consumer Earthworm Bracket fungus Rotting log Millipede Bacteria, archaea (many species) Puffball Dead leaves (many species) Pillbugs Insect larvae (maggots) Dead animals (many species) Cricket Maple tree leaves Figure 54-7 Production of biomass (g/m2/year) Tertiary consumers 3 Secondary consumers Primary consumers and decomposers Primary producers 30 10% 15% 200 Efficiency of energy transfer 20% 1000 Types of predator/prey relationships True predators-kills and eats another animal Parasites-are only predatory if they kill their host Parasitoid-insects that lay eggs on a host. The larvae are parasitic to the host Herbivores-yes, they’re technically predators. Some are seed-eaters (granivores), some eat grasses (grazers), and some eat other plant material (browsers) Avoiding Predation Organisms have evolved many mechanisms for avoiding predators. Secondary Compounds-toxic chemicals produced by plants that can make herbivores sick Camouflage (cryptic coloration)-helps the animal blend into it’s surroundings (some predators use this as well to help them hunt) Aposematic coloration (warning coloration)-a bright color pattern that advertises that the organism should be avoided (ex: wasp/bee stripes) Mimicry-organisms resembling each other (shortens the predator’s learning curve) Mullerian mimicry-dangerous organisms resemble each other Batesian mimicry-organisms without a defense mechanism resemble a dangerous organism Figure 53-12 Cottonwood tree felled by beavers Resprouted trees have more defensive compounds. Survival of beetle larvae placed on ant mound Figure 53-10 Prey and predator Blue mussels Crabs Correlation between predation rate and prey defense Figure 53-9 Constitutive defenses of animals vary. Camouflage: blending into the background Schooling: safety in numbers Weaponry: fighting back Mimicry can protect both dangerous and harmless species. Müllerian mimics Paper wasp Bumblebee Batesian mimics Honeybee Hornet moth Wasp beetle Hoverfly Symbiosis-a different kind of relationship In a symbiotic relationship, organisms closely associate with one another. There are 3 types of symbiosis: Parasitism-1 organism benefits, the other is harmed Commensalism-1 organism benefits, the other is neither harmed nor benefitted Mutualism-both organisms benefit Figure 53-16-Table-53-1 Coevolution in Relationships Organisms often respond to changes in other organisms through coevolution. For example, hummingbirds find nectar by color, so the flowers that attract them are tube-shaped, are bright red, and have virtually no scent Often, plants can only be pollinated by one type of pollinator, so they evolve together Biodiversity This is also called species diversity and can be discussed in terms of Species richness-number of different species in the community Relative abundance of different species in the community This is a measure of heath of an ecosystem Diseases are specific to the organism If 1 food source dies, there are others, etc Figure 53-25 Community 2 Community 3 Species richness: 6 6 5 Species diversity: 0.59 0.78 0.69 Community 1 A B C Species D E F Figure 55-4 Hotspots in terms of species richness of birds Hotspots in terms of endemic species of birds Hotspots in terms of high proportion of endemic plants and high threat High Impact Species in Communities Keystone Species-These are not necessarily abundant in a community, but play a part in many interactions within the community. You can tell a keystone species by removing it from the ecosystem and viewing the impact. (ex: sea otters, if removed don’t keep sea urchins in check, and there’s less kelp) Invasive Species-These are species that invade (usually by being introduced by humans) an ecosystem and replace the species that are naturally there Dominant Species-These are the most abundant species in an ecosystem, and have the most biomass Foundation Species-These are also called Ecosystem engineers, and they cause physical changes in their environments. Beavers are examples of this type of species. Facilitators are foundation species that have a positive impact on the environment Figure 53-18 Predator: Pisaster ochraceous Prey: Mytilus californianus Figure 55-7 Invasive species increase competition. Purple loosestrife is crowding out native organisms in North American marshes. Invasive species introduce disease. Invasive species increase predation. An introduced fungus has virtually wiped out the American chestnut. The brown tree snake has extinguished dozens of bird species on Guam. Figure 53-19 P. ochraceous (keystone predator) present P. ochraceous (keystone predator) absent Community Change Succession-a series of more-or-less orderly changes in an ecosystem over time. Begins with a pioneer species (usually an r-selected species) and ends with a climax community (stable) In general, as organisms inhabit the area, they changes the texture, pH, and water potential of the soil, as well as establish competition for resources as the area becomes crowded Primary Succession-occurs on a substrate that has never before supported life. Secondary Succession-occurs on a substrate that has gone through some sort of disturbance Succession on land In primary succession, generally starts with lava flow or sand. Pioneer for lava-lichens Pioneer for sand-grasses In secondary succession, you can start at any point in the successional process, usually a field. These used to be thought of as a predictable series of changes, however, there are instances that are more random and less orderly b/c they’re affected by climate, which species happen to arrive first, etc. Figure 53-21-1 Old field Disturbance (plowing) ends, site is invaded by short-lived weedy species. Pioneering species Figure 53-21-2 Weedy species are replaced by longer-lived herbaceous species and grasses. Early successional community Shrubs and short-lived trees begin to invade. Mid-successional community Figure 53-21-3 Short-lived tree species mature; long-lived trees begin to invade. Late-successional community Long-lived tree species mature. Climax community Succession in Water This happens when you start with a lake or pond that changes to a marsh-like state. The marsh is followed by meadow, with lots of grasses. Finally, there’s a climax community of native vegetation Ecosystem Ecology Biogeochemical Cycles-this is the flow of important elements through the ecosystem. Hydrologic cycle-mainly an abiotically-driven cycle. Reservoirs-ocean, air, groundwater, glaciers Assimilation-plants absorb water from the soil, animals drink water and eat organisms Release-transpiration, evaporation, etc. Carbon cycle-mainly biotically-driven and tied to atmospheric CO2 levels that cause the greenhouse effect Reservoirs-atmosphere, fossil fuel, peat, organic material (like cellulose) Assimilation-photosynthesis, animals eating plants and each other Release-respiration and decomposition Nitrogen cycle-also a biotically driven cycle dependent heavily on bacteria Reservoirs-atmospheric N2, soil (nitrates, nitrites, ammonium, amonia) Assimilation-nitrogen fixation by bacteria, nitrification by bacteria Release-denitrification by bacteria, decomposition, animal waste Phosphorous cycle-again, a biotically-driven cycle Reservoirs-rocks and ocean sediments Assimilation-plants absorb phosphates and are eaten by animals Release-decomposition, animal waste Figure 54-13 THE GLOBAL WATER CYCLE All values in 1018 grams per year Evaporation from ocean: 319 Net movement of water vapor by wind: 36 Precipitation over ocean: 283 Evaporation, transpiration: 59 Precipitation over land: 95 Percolation Water table (saturated soil) Figure 54-14 THE GLOBAL CARBON CYCLE All values in gigatons of carbon per year Net uptake via photosynthesis, chemical processes: 1.5 Atmosphere: 778 (during 1990s) Net uptake via photosynthesis by plants: 3.0 Land-use change (primarily deforestation): 1.6 Fossil-fuel use: 6.3 Organisms, soil, litter, peat: 2190 Organisms, chemical processes in ocean: 40,000 Aquatic ecosystems Rivers (erosion): 0.8 Terrestrial ecosystems Human-induced changes Figure 54-16 THE GLOBAL NITROGEN CYCLE All values in gigatons of nitrogen per year Atmospheric nitrogen (N2) Internal cycling: 8000 Bacteria in mud use N-containing molecules as energy sources, excrete N2: 310 Nitrogen-fixing cyanobacteria: Runoff: 36 15 Mud Permanent burial: 10 Protein and nucleic acid synthesis Industrial fixation: 100 Lightning and rain: 3 Internal cycling: 1200 Decomposition of detritus into ammonia Nitrogen-fixing bacteria in roots and soil: 202 Biomes These are ecosystems that have characteristic biotic and abiotic factors Land Biomes are largely determined by latitude (except desert which is determined by climate) As you move from the poles toward the equator, biodiversity and biomass increase. The length of the growing season also increases. Water Biomes are determined by salinity and depth Land Biomes In the tropics: Rain forest-200-400 cm of rain annually Savanna-30-50 cm of rain annually In the temperate zone: Deciduous forest-70200 cm of rain annually Grassland-30-100 cm of rain annually Chaparal-30-50 cm of rain annually (coastal region) Northern Coniferous forest (Taiga)-30-100 cm of rain annually Tundra-20-60 cm of rain annually Desert-occurs at any latitude-less than 30 cm of rain annually Figure 50-9 Barrow Dawson Chicago Konza Prairie Yuma Belém Figure 50-23 North pole Small amount of sunlight per unit area Low angle of incoming sunlight Moderate angle of incoming sunlight Sunlight directly overhead Large amount of sunlight per unit area Figure 54-11 Boreal forest: Accumulation of detritus and organic matter Tropical wet forest: Almost no organic accumulation Organic matter Organic matter Figure 50-12 Tropical wet forests are extremely rich in species Figure 50-11 Figure 50-18 Temperate forests are dominated by broadleaved deciduous trees Figure 50-17 Figure 50-16 Grasses are the dominant lifeform in prairies and steppes Figure 50-15 Figure 50-20 Boreal forests are dominated by needled-leaved evergreens, such as spruce and fir Figure 50-19 Figure 50-22 Arctic tundra is dominated by cold-tolerant shrubs, lichens, and herbaceous plants Figure 50-21 Figure 50-26 Air rises over mountains and cools; rain falls East Dry air creates desert conditions West Moisture-laden air blows onshore from Pacific Ocean Cascade Mountains This area is in a rain shadow Figure 50-14 Saguaro cacti are a prominent feature of the Sonoran Desert in the southwestern part of North America Figure 50-13 Water Biomes Freshwater: Lakes Streams and Rivers Wetlands Brackish: Estuaries Marine: Intertidal Zone Oceanic Pelagicsplit into the photic and aphotic zones Coral reefs-always in the photic zone Benthic-ocean bottom Figure 50-5 Bogs are stagnant and acidic. Marshes have nonwoody plants. Swamps have trees and shrubs. Figure 50-3 Photic zone Aphotic zone Primary Productivity This is the amount of light energy converted to chemical energy in an ecosystem. Gross Primary productivity-is the total primary productivity of the ecosystem Net Primary productivity-is the gross primary productivity- the energy used by producers for respiration (R) Formula for net primary productivity: NPP=GPP-R Figure 54-3 NPP per unit area Aquatic Terrestrial Area covered, by ecosystem type Total NPP Human Impact on the Biosphere Human activity over time has been damaging to the biosphere. Ecology is really a study of balance, and as the human population has grown, our wastes and byproducts have thrown off that balance. There have been, in recent years, efforts to reestablish the balance and conserve our resources. Ex: Prior to the 1980s, CFCs were common propellants used in household goods. As a result of human use of CFCs, they built up in the atmosphere, reacting with ozone (O3), and causing holes in the ozone layer. This layer surrounds the planet and shields us from damaging UV radiation. As a result of banning CFCs, and using safer alternatives, the holes in the ozone layer are repairing themselves. Climate change Human activities have caused a buildup of CO2 in the atmosphere. Of course, CO2 is a greenhouse gas, which means that we have additional heat building up in our atmosphere Data indicates that the world is getting warmer, which sparks many problems like raising sea levels, changing weather patterns that could decrease agricultural output, change the trophic structure of our oceans and land Figure 54-15b Recent changes in atmospheric CO2 recorded in Hawaii At Mauna Loa, atmospheric CO2 concentrations are high in winter and low in summer, forming annual cycles Figure 54-19 Cold-water copepods are declining in the North Atlantic. Flowering times for some species in midwestern North America are earlier in the year. Great Britain Cold-water copepods Warm-water copepods Baptista flowers Figure 54-21 Much of the ocean is stratified by density and temperature. Global warming increases the density gradient, making it less likely for layers to mix. Surface layer: Water is much warmer, less dense Surface layer: Water is warm, less dense Density gradient Nutrient-rich water is brought to the surface by currents Benthic zone: Water is 4°C, highest density Much steeper density gradient Currents are less likely to bring nutrient-rich water to surface, against the steeper density gradient Benthic zone: Water is 4°C, highest density Pollution Obviously, this causes destruction of water, air, and land resources, as they become fouled by waste. This has obvious negative side-effects for orgnisms on the planet, but there are 2 important issues associated with pollution that aren’t always discussed. Biological magnification-while energy decreases as it moves up the food chain, pollutants and toxins, like DDT, concentrate. Eutrophication-believe it or not, this IS a bad thing. Over-fertilization nourishes the water, causing algal blooms. Not only can these be toxic to animals, but they are r-strategists, so they die, sink, and are decomposed at the bottom of bodies of water (mainly freshwater). Decomposition is an oxygen-consuming process, which leaves the bottom waters anoxic, causing fish-kills Other Environmental Problems Acid Rain-Sulphur-containing compounds belched from smokestacks turn into sulphuric acid in the atmosphere Deforestation-clear-cutting of forests for logging and expanding human population. This is particularly bad b/c the nutrients in tropical rain forests are in the canope. Desertification-overgrazing of grasslands bordering deserts turns these into deserts. All of these can lead to endangerment of or reduction in species and biodiversity. Figure 55-10 The devastation of deforestation Satellite view of deforestation in Rondônia, Brazil 1975 2001 Figure 55-6 Terrestrial Freshwater Marine Sustainable Practices These are things that humans can do to reduce our impact on the biosphere. Examples include: reforestation, smoke-stack filters, reduction of fossil fuel consumption, smart use of fertilizers, plowing and strip cropping to reduce erosion, use of biological methods for controling pests, establishing protected areas, etc