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5 Levels of Ecological Organization § Species- organisms that can interbreed and produce fertile offspring § Population- all the members of 1 species in an area § Community- every species in an area § Ecosystem- many communities and their environment § Biosphere- the entire region of Earth where living things can be found (many ecosystems) What is Ecology? § Ecology- study of the interaction between organisms and their environment § Within an ecosystem there are two main components Habitat- place where organism lives Community- ALL the species in habitat Biomes § Biomes are groups of terrestrial ecosystems that have the same climate and dominant communities § 3 types of biomes: l Temperate: seasonal l Tropical: by equator and hot year round l Arctic: far from equator and cold year round § You have forests, deserts and grasslands in these different areas Biomes Aquatic Lifezones § Aquatic lifezones are aquatic ecosystems. § Freshwater or saltwater § Freshwater l Wetlands are very important ecosystems l Bogs, swamps or marshes l Rivers l Ponds l Estuaries (wetlands where river meets sea) l Mangrove swamps § Saltwater (Marine) l Coral Reefs l Intertidal zone l Open ocean § Biomes-22min Species Interaction § Many interactions take place between species in a community i.e.) predator and prey § Each organism plays a certain role in the community § Niche- role of an organism in which it interacts with other species and its environment (i.e. its job) Abiotic vs. Biotic Factors § Abiotic- “non-living” components -ex) temperature, light, water, nutrients, boats § Biotic- “living” species -ex) sea turtle, sea grass, coral, fish, humans Biotic Factors § Two categories of life based on how they get energy § All life is either a l l Producer OR Consumer Biotic Factors § Producers- organisms that are capable of producing their own energy source l l l Photosynthetic (plants that take light to make carbs) Chemosynthetic (some bacteria that can take chemicals to make their carbs) All producers are autotrophs or “self-feeders” KNOW THIS EQUATION! Biotic Factors § Consumers- organisms that can’t produce their own energy source, but have to consume it from another source l All consumers are heterotrophs or “other feeders § Many different types of consumers (heterotrophs) -Herbivores -Carnivores -Omnivores -Decomposers Look at each of the pictures and write in the space below it whether it is a producer or a consumer Conditions for Life § For an ecosystem to sustain life, it must have: l l l l 1) Constant source of energy (sun). 2) Living system that converts sun’s energy into organic molecules. Plants! 3) Cycling of nutrients between organisms and environment (water, carbon dioxide, nitrogen, oxygen). 4) Decomposers- bacteria and other small organisms that breakdown and return unused nutrients to the environment. Biodiversity § Biodiversity- The number of different species in an ecosystem l l More plants = more animals More biodiversity = healthier ecosystem What Determines Biodiversity of Ecosystem? § Size § Latitude – Closer to equator = more diverse. a) More sunlight and longer growing season b) More producers (plants) Why do we call plants producers? c) More producers = more consumers § Precipitation (i.e. rainfall) Nutritional Interactions § All ecosystems must have interactions between producers, consumers, and decomposers § These interactions transfer nutrients and energy throughout the ecosystem Energy flow in an ecosystem § Energy flows through an ecosystem from the sun to producers to consumers § ***Arrows show the direction the energy flows “Who Eats Who”… § Food chain- straight line sequence shows simple feeding relationships § Notice the direction of the arrows! § Sun § Producers § Primary consumers § Secondary Consumers § Tertiary Consumers OWL Quaternary consumer FLOWER Producer FROG Secondary consumer CATERPILLAR Primary consumer SNAKE Teriary consumer § Food webillustrates how many food chains in an ecosystem are related § Primary consumers? § Secondary consumers? § Tertiary consumers? § Where would decomposers fit in this food web? How many trophic levels are possible? § Energy pyramids- show amount of energy at each trophic level § These are not food pyramids!! § Trophic levels -levels of feeding from producers (plants) to the consumers l l Few ecosystems have more than 4 or 5 trophic levels Energy diminishes at each level because it is used for life’s processes Pyramid of Energy §Which level has the most energy AVAILABLE? § Trophic levels l l l l Producers have the most energy available Primary consumers are all herbivores Secondary consumers are small carnivores Tertiary consumers are large carnivores § Part of the original energy from the sun is used at every level by the organisms for survival How do organisms obtain nutrients? § Although energy moves through ecosystems in a one-way direction, nutrients are recycled § Three basic nutrient cycles are present in all ecosystems allowing organisms to obtain needed nutrients to function effectively Nitrogen Cycle §The atmosphere contains 80% nitrogen gas (N2) §However, this nitrogen can not be used by most living things §Bacteria are the only organisms that use nitrogen gas directly from the atmosphere §They can fix nitrogen for plants to use by converting it into ammonia N2 DNA and proteins Nitrogen Cycle Processes §Nitrogen fixation- nitrogen N2 gas in atmosphere converted to ammonia, NH3 (bacteria in soil, lightning)Nitrogen fixation §Nitrification- bacteria converting ammonia to NH3 nitrate (another form of nitrogen) §Assimilation- absorption Nitrification of ammonia and nitrate by plants YUMMY! Assimilation Nitrate Nitrogen Cycle Processes § Ammonificationdecomposers (bacteria and fungi) break down of dead organisms and waste and return nitrogen to soil as ammonia § Denitrificationconversion of ammonia back to nitrogen gas (decomposers) N2 Denitrification Ammonification NH3 Nitrogen Cycle Review Nitrogen Importance § Why is nitrogen important to living things? § How do plants obtain nitrogen? § Why are bacteria SO important to the nitrogen cycle? § How do we obtain nitrogen? § Nitrogen cycle movie with QUIZ Water Cycle § Driving force is the sun and gravity § Consists of the alternation between evaporation and precipitation § Most water returned to the atmosphere comes from evaporation from the oceans Water Cycle Processes § Water vapor- gaseous form of water in atmosphere § Evaporation- liquid water from bodies of water becomes gas returned to atmosphere § Transpiration- loss of water by land plants Water Cycle Processes § Condensationprocess which water molecules gather in atmosphere “change from gas to liquid” when cooled § Precipitation- water falls from atmosphere to ground (rain, snow, sleet, or hail ) Water Cycle What is missing here? Why is the water cycle important? § Water is the most important nonliving (abiotic) component of an ecosystem § Water essentially determines what organisms we find in an ecosystem l Tropical rainforest vs. desert Carbon Cycle § Carbon cycles between the living organisms and the non-living components of ecosystem § Carbon exists in the atmosphere as carbon dioxide (CO2) § Plants are of great importance to the carbon cycle!!—photosynthesis takes carbon from the air and creates glucose for all consumers to use § Why do living things need carbon? 6 C Carbon 12.011 Carbon Cycle Processes § Photosynthesis- process where sunlight, CO2 and H2O is used to make carbs. CO2 + H2O + sunlight (energy) glucose (carb) +O2 § Respiration- process by which animals use carbs, taking in O2 given off by plants and give off CO2 ***THE OPPOSITE OF PHOTOSYNTHESIS! glucose (carb) + O2 CO2 + H2O + energy to live Respiration § The energy for life’s processes comes from cellular respiration, which occurs in your mitochondria glucose (carb) + O2 CO2 + H2O + ATP energy Carbon that you eat is used to build other organic macromolecules or is exhaled This carbon that you exhale is from the food you eat Carbon Cycle Processes § Decomposition—breakdown of dead organisms and waste, returning carbon to the soil and atmosphere § Fossil fuels- formed by pressure applied to dead organisms that are buried in sediment. They are carbon and release CO2 when burned. § Combustion- burning of fossil fuels Carbon Cycle Why is the carbon cycle important? § Organic macromolecules – carbon compounds used for energy for living organisms (carbohydrates), cell membranes (lipids), DNA/RNA, and proteins. § ***Humans are altering this cycle l l Deforestation releases stored carbon CO2 from burning is a greenhouse gas which warms the planet Why is the carbon cycle important? § Burning too many fossil fuels releases extra CO2 into the atmosphere l l l l This creates climate change due to increased greenhouse effect The greenhouse effect is normal Climate change is due to abnormally high levels of the greenhouse effec Greenhouse effect video clip Average Surface Temperature (°C) Average Temperature Over Past 130 Years 15.0 14.8 14.6 14.4 14.2 14.0 13.8 13.6 1860 1880 1900 1920 1940 Year 1960 1980 2000 2020 What is the Scientific Consensus? Mean global temperature rose about 0.6º C (1.5º F) since 1880 1979--NASA Increase is real, not explained by natural variation in solar radiation Warming greater at poles than equator, greater at night, mostly troposphere September sea ice level animation 2003--NASA How competition effects ecosystems § Sometimes two species will compete § Competitive exclusion- no two species can occupy the exact same niche (job) for a long period time § Only one species wins What if no one wins? § In some species interactions, neither species wins § This results in close, long term associations within an ecosystem called symbiotic relationships § § § § 3 Kinds of Symbiotic Relationships +=helped - = harmed 0=neither Parasitism (+/-) § Commensalism (+/0) § Mutualism (+/+) Evolution and Ecology § Symbiotic relationships cause species to evolve in response to each other l Ex) Flowers pollinated by nocturnal moths § Coevolution- evolution of two or more species in response to one another § Ant and Fungus Symbiosis Changing Ecosystems • Infer….what do you think is the story behind the picture? • Changes are a natural part of any ecosystem • Succession- regular development of an ecosystem which leads to gradual replacing of species in a community by others • Succession and the Mount Ecosystem Stability § Does succession ever end? § Climax community § Stability - ability of an ecosystem to resist change when a disturbance occurs § Biodiversity tends to promote stability Ecosystem Stability § Keystone speciesspecies that are crucial to the stability of an ecosystem § If members of a keystone species die, then the entire ecosystem can collapse l i.e. sea otters- keep sea urchins in check, which would take over the kelp beds without the otters Ecosystem Stability § Invasive, or introduced species- those that are brought by humans accidentally or purposefully from other places l l l Invasive/introduced species can take hold and destroy ecosystems. They multiply out of control due to lack of predators in new place they are moved to. Ex: Asian longhorn beetle, Zebra mussels SEA LAMPREY Population Dynamics § Population-a group of organisms of the same species that occupy a given area § Living things reproduce § If environmental conditions are “favorable,” then the number of individuals in population should increase from one generation to next Population Size- Growth Rate Birth rate- # individuals born Death rate- # individuals die Immigration- # individuals move in Emigration- # individuals move out If… BR + I = DR + E EQUILIBRIUM BR + I > DR + E INCREASING BR + I < DR + E DECREASING § Population growth video clip § § § § § Biotic Potential § Under favorable conditions, a species may reach its biotic potential § Biotic potential- highest reproduction rate possible for a species under “ideal” conditions. Ex) Houseflies -Lay over 100 eggs at once -Can reproduce at 1 month old -After 7 generations, one fly = 15 billion flies!!! Exponential Growth § Exponential growth- starts out slowly but then grows rapidly to infinitely high numbers l l Represented by “J curve” This does NOT describe real populations forever § Something always limits growth eventually biotic potential Factors Affect Growth Rate Size of Population § Environmental resistance- “limiting factors” that stop populations from reaching their biotic potential l l l l l l Space Water Nutrients Competition Disease Natural disasters Logistic Growth § Real populations can only grow exponentially for short spans. § Environmental resistance limits size of a population. § Logistic curvepopulation growth that levels off due to environmental resistance l “S” curve Carrying Capacity § Carrying capacitytotal # of individuals that can be supported by the environment in a particular area § Earth has over 7 billion people…how many more can it support? § Population Crash The Human Population World Populaton Clock § The human population is growing exponentially at 1% a year l Adding 1 million people every 5 days § Remember that exponential growth cannot continue forever § Humans are subject to the same laws of nature as all other species Problems with Overpopulation Humans, more than anything else, are affecting the stability of Earth § 1.) Food supply increased over past few decades, but amount per person has decreased l l l Many people starving, and this will continue to get worse as over 90% of future population growth is expected to occur in less developed nations Over-fishing Erosion and pollution of agricultural land Problems with Overpopulation § 2.)Energy shortage l Nonrenewable resources are limited and we are using them faster than ever before • Less developed nations who are developing will continue to use more fossil fuels • The U.S., with 5% of the world’s population, uses 25% of the world’s energy resources • Pollutants are increasing as well as climate change Problems with Overpopulation § 3.)Destruction and abuse of natural resources l l l l Topsoil Forests Freshwater supplies diminished Species extinction Problems with Overpopulation § 4.)Pollution • Production of tons of unnecessary solid waste • Water • Air – Climate change due to burning and deforestation increasing carbon dioxide levels – Acid rain – Ozone depletion Ozone Layer Depletion § Ozone shield l l Ozone (O3) in the atmosphere protects us by absorbing harmful UV light 1970s scientists discovered the ozone layer over Antarctica has decreased by as much as 60 % § Problems? l l UV light is a mutagen, which can cause skin cancer Cataracts