OBJECTIVE. Describe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, biosphere)

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2 LEARNING OBJECTIVES Describe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, biosphere) Describe the characteristic biotic and abiotic components of aquatic and terrestrial ecosystems Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids) Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle) Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires) Describe the effects of limiting factors on population dynamics and potential species extinction

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4 OBJECTIVE Describe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, biosphere)

5 ECOLOGY INTRODUCTION Ecology the study of an organism s interaction with its environment Includes interactions with living and non-living parts of the ecosystem System set of interacting components that form an integrated whole. Open system: interact with its environment Closed system: isolated from its environment Environment total surroundings of an organism or group of organisms

6 LEVELS OF ECOLOGICAL ORGANIZATION Ecology can be studied at various levels Organism Population Community Ecosystem Biome Biosphere

7 ORGANISM Individual member of a species

8 POPULATION All the members of one species living in an area Species: all organisms capable of reproduction that results in fertile offspring

9 COMMUNITY All of the organisms living in an area

10 ECOSYSTEM All of the organisms as well as the nonliving things in an area (a community plus nonliving things)

11 BIOME A generic type of ecosystem that can be found in multiple locations throughout the world Terrestrial biomes (land based) Rainforest Savanna Temperate forest Desert Temperate grassland Chaparral Taiga (boreal forest) Alpine Tundra Temperate Grassland Desert

12 BIOMES (CONTINUED) Aquatic biomes (water based) Freshwater Freshwater wetlands Marine Coral Reefs Estuaries Freshwater Wetland Coral Reef

13 BIOSPHERE The entire livable portion of planet earth Extends about 5 miles up and down from sea level

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15 OBJECTIVE Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems

16 BIOTIC AND ABIOTIC FACTORS Biotic components of an ecosystem All living things The plants & vegetation type determine the types of animals that are present Abiotic components of an ecosystem Nonliving factors of an ecosystem Temperature Rainfall Elevation Wind Fires Abiotic factors determine plants & vegetation

17 TEMPERATURE & LATITUDE Temperature is largely determined by the amount of direct sunlight that is received Generally, the closer to the equator the warmer it is Summer Winter

18 RAINFALL Rainfall can vary from 0 to nearly 700 of rain per year (Philadelphia, PA averages about 42 ) Very cold areas usually very dry Rainfall is determined by wind and ocean currents as well as local topography Mountain ranges often have a wet and dry side (rain shadow)

19 OTHER ABIOTIC FACTORS Winds high winds can limit tree growth Fires in areas that have frequent fires, plants either need to regrow (grasses) or be fire resistant (bristlecone pines) Elevation higher elevations can be very cold and windy The Himalayas are near the equator, but the ecosystems resemble tundra

20 ABIOTIC FACTORS OF AQUATIC ECOSYSTEMS Water movement caused by river currents, ocean currents, waves, wind, and tides Organisms either need to fasten to the bottom or float or swim in the water Water chemistry salinity, nutrients, dissolved oxygen and more Salinity ranges from freshwater to saltwater Estuaries are unique ecosystems that exist in the transition between fresh and saltwater (brackish water) Nutrients amount of nutrients limits growth of plants and algae Too much nitrogen can cause algal blooms. Dissolved oxygen fish and other animals still need oxygen Cold water has more oxygen than warm water Depth has a large impact on amount of light as well as pressure

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22 OBJECTIVE Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids)

23 ENERGY IN ECOSYSTEMS Virtually all ecosystems rely on photosynthesis to capture energy from the sun Exception: deep sea hydrothermal vents rely on energy from chemicals formed in volcanically heated water Energy Laws: 1. Energy is not created or destroyed 2. Energy can be transferred 3. Every time energy is transferred, some energy is lost in the form of heat

24 FOOD CHAINS Simplistic way to trace the flow of energy from the bottom to the top Levels also called trophic levels 1. Producers (plants and algae) 2. Primary consumers (herbivores) 3. Secondary consumers (carnivores) 4. Tertiary consumers (predators) 5. Quaternary consumers (top predators) 6. Etc.

25 FOOD WEBS More complex than a food chain Shows multiple energy sources of most animals Many animals may fall on different levels depending on what they eat (especially omnivores)

26 ENERGY SUPPLY As energy is transferred up the food chain, more and more is lost in the form of heat Energy Pyramid shows the flow of energy From producers to primary consumers and to higher trophic levels Energy transfer is measured using biomass Ecosystems rarely have more than 4 or 5 levels because there is not enough energy at the top to support a population of that species. Only 10% of the energy stored at each trophic level is available to the next level

27 Tertiary Consumers 10 kcal Secondary Consumers 100 kcal Primary Consumer 1,000 kcal Producers 10,000 kcal 1,000,000 kcal sunlight

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29 HOW DOES THIS AFFECT HUMANS? When we eat grains or fruit we are consuming at what trophic level? Primary consumer When we eat beef or other meat from herbivores we are consuming at what trophic level? Secondary consumer When we eat fish, like trout or salmon, we are eating at what trophic level? Tertiary or quaternary consumer

30 HOW DOES THIS AFFECT HUMANS? We know: 10% of chemical energy is available in a trophic level to pass on to the next trophic level Therefore: The human population has 10 times more energy available to it when people eat plants instead of meat Eating meat of any kind is expensive economically and environmentally.

31 Secondary Consumers Primary Consumer Producers 1,000,000 kcal sunlight

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33 OBJECTIVE Describe biotic interactions in an ecosystem (e.g., competition, predation, symbiosis)

34 BIOLOGICAL INTERACTIONS Symbiotic relationship an interaction between two organisms in an ecosystem Every species has dozens of symbiotic relationships In many cases a species may have some benefit or loss because of the relationship

35 PREDATOR / PREY Predator eats prey Herbivory (eating plants) is similar Creates evolutionary pressure for adaptations (coevolution) Predators need adaptations to catch prey Prey need adaptations to avoid being eaten

36 COEVOLUTION Two species are so dependent on one another, they can drive one another s evolution. Strongest in predation, mutualism, and competition Predation: boom and bust cycles Can be caused by food shortages or predator/prey interactions

37 PARASITE / HOST Similar to predator / prey in that there is a clear winner and loser The main difference is that parasites rarely kill their hosts Parasites can take energy or other resources (blood, sap, light, shelter, food, energy, etc.)

38 COMPETITION The resources a species uses in its environment is called its niche Competition occurs when two or more species occupy the same niche Meaning they use the same resource In this case both organisms lose out because they are fighting for a limited resource Resources can vary (food, shelter, light, nutrients, etc.)

39 LIMITING FACTORS One or more environmental factors that limit the growth rate of a population Food supply Space/nesting sites Competition Number of females/males

40 FUNDAMENTAL VS. REALIZED NICHE

41 COMMENSALISM One species benefits and the other does not benefit or lose Examples: Remora & shark Clownfish & anemone

42 MUTUALISM Both species benefit Can be extreme enough that species cannot live without one another Examples: Cleaner fish Human & E. coli Flowers & insects

43 POPULATION DYNAMICS Studying the changes in population size Under ideal conditions, populations increase exponentially Eventually, one or more limiting factors restrict population growth (carrying capacity) K = carrying capacity of ecosystem N = number of individuals t = time

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45 OBJECTIVE Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)

46 CHEMICAL CYCLING There is not an extraterrestrial source of chemical elements Life depends on the recycling of chemicals

47 NITROGEN CYCLE An ingredient of proteins and nucleic acids (DNA, RNA) Essential to the structure and function of all organisms Crucial and often limiting plant nutrient Two abiotic reservoirs of nitrogen: The atmosphere (80% is nitrogen gas, N 2 ) Soil Depends on bacteria

48 NITROGEN CYCLE Nitrogen gas = N 2 Nitrate = NO 3 - Ammonium = NH 4 + Nitrogen fixation = converting nitrogen gas to ammonium Nitrification = converting ammonium to nitrates Assimilation = plants taking in nitrates from the soil and using it for their processes Denitrification = converting nitrates to nitrogen gas Decomposition = breaking down orfdead organisms, returning elements to the environment Decomposer = organisms (fungi, bacteria) that consume dead organisms for energy

49 NITROGEN CYCLE

50 EUTROPHICATION Producer growth is limited to availability of nitrogen Standing water ecosystems accumulate nutrients from decomposing matter and entry from the land (mostly from agriculture) This causes producer growth to increase (eutrophication)

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52 EUTROPHICATION Eutrophication of lakes, rivers, and coastal waters Depletes oxygen levels Decreases species diversity Aquatic eutrophication results from increased levels of nitrogen Feedlots Applications of large amounts of fertilizer

53 MISSISSIPPI RIVER BASIN

54 CONSEQUENCES Red and orange indicates highest levels of phytoplankton

55 WATER CYCLE Greatest source of water is the oceans Evaporation moves it to the atmosphere and sometimes on to land Water can cycle on land All powered by the sun

56 WATER CYCLE Evaporation = state of water changes from liquid to gas Transpiration = water evaporating from trees and other plants Condensation = state of water changes from gas to liquid Precipitation = water in various forms falling back to earth s surface Ground water = water found under the ground s surface Aquifer = large underground lake, stores large amounts of liquid water

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58 CARBON CYCLE Carbon dioxide is absorbed by plants and forms sugars through photosynthesis Cell respiration releases carbon back into the atmosphere The burning of fossil fuels has greatly increased the carbon dioxide in the atmosphere

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61 OBJECTIVE Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires)

62 CHANGES TO ECOSYSTEMS Ecosystems are in constant change Stable ecosystems may change very slowly Disturbances can cause drastic changes Natural vs. Human caused changes Disturbances can be natural (fire, pioneer species, disease, natural weather anomalies, population fluctuations) Humans can cause many disturbances, some similar, some not (fire, introduced species, climate change, pollution)

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64 SECONDARY SUCCESSION After a disturbance like a fire where most or all life is destroyed, the ecosystem progresses in a predictable pattern Pioneer species like grasses and wildflowers grow first soil is still present This changes the ecosystem to make it suitable for bushes and eventually trees (this can take 100 s of years) The stable ecosystem that results is called a climax community The climax community generally remains stable until the next major disturbance

65 PRIMARY SUCCESSION Similar to secondary, but in this case there is no existing soil Lichens, mosses and weather will take many years to create suitable soil for other plants Common examples are new land formed by lava and land that has been scraped clean by a glacier

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67 INVASIVE SPECIES Humans have greatly increased the number of species being introduced in new environments Occurs purposefully (Purple Loosestrife) as well as accidentally (Stink bug & Japanese Beetle) Some introduced species are extremely successful because they lack the native predators and diseases Can cause agricultural damage as well as the extinction of native species Island such as Hawaii have been devastated by invasive species like the rat

68 CLIMATE CHANGE Humans have introduced excess greenhouse gases in the atmosphere (mostly carbon dioxide from burning fossil fuels) Excess greenhouse gases are trapping more heat in our atmosphere Could have vast impacts on all ecosystems due to climate fluctuations and ocean levels

69 POLLUTION Humans have introduced other things that negatively affect ecosystems Pollution comes in many forms: air, water, light, thermal, noise Air pollution: Some areas locally affected by smog and other dangerous chemicals Emissions of greenhouse gasses may cause global issues Water pollution: Most common pollution is excess nutrients that cause algal blooms and kill fish Other chemicals can be directly or indirectly toxic to living things Even the oceans are showing signs of stress

70 LOSS OF BIODIVERSITY Rainforest Cleared for Farming The rate of species extinction has greatly increased in the last 200 years The greatest cause of extinction is habitat loss Rainforests and coral reefs are two ecosystems that have high biodiversity and have been severely impacted by human activities Florida Panther