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CHAPTER 4: CHARACTERISTICS IN ECOSYSTEMS Pages 84-131 Nelson 1 Section 4.1 Recall: An environment includes biotic and abiotic components. Interactions between organisms and their environment can be divided into four levels: individuals, populations, communities, and ecosystems. Individuals Species: organisms that are able to breed with one another and produce fertile offspring. Population: a group of individuals of the same species living in a specific area Community: all of the individuals in all of the interacting populations at a given time Ecosystem: a community of populations together with the abiotic factors that surround and effect it. ECOSYSTEM INTERACTIONS ECOLOGY: the study of interactions between organisms and their biotic & abiotic environment Recall examples of interactions: Biotic-Biotic: moose eating grass Abiotic-Biotic: sunlight on plants Abiotic-Abiotic: river eroding rocks BIODIVERSITY WITHIN ECOSYSTEMS ECOTONE: a transition area between ecosystems ecosystems don’t have sharp boundaries organisms move back and forth from one ecosystem to another therefore the ECOTONE between 2 ecosystems has greater biodiversity see Fig. 1 p.87 remember, areas with greater biodiversity are MORE STABLE ROLES WITHIN ECOSYSTEMS NICHE: an organism’s role in an ecosystem -its place in the food web -its habitat -its breeding area http://en.wikipedia.org/wiki/File:Dung_beetle_working-001.ogv NOTE: each species in an ecosystem tends to have a different niche (read page 90) Niche Helps us to understand how organisms in an ecosystem interact with each other. The ecological niche of a population is the role that its members play in an ecosystem. Eg. Honeybees gather nectar from flowers to make honey - Pollinators Community Ecology: Feel the Love - Crash Course Ecology #4 http://www.youtube.com/watch?v=GxE1SSqbSn4 COMPETITION FOR NICHES if a new species enters an ecosystem (called an EXOTIC SPECIES), it often causes a disturbance Why??? it competes for a NICHE already occupied by a native species it may have no natural predators it may bring new disease that native species aren’t immune to Read ‘Intro of exotic species’ p.91-92 Attack of the killer Cane Toads in Australia! introduction of exotic species 14 Cane toad vs. fresh water crocodile … who wins? https://www.youtube.com/wat ch?v=w2bwUlu3eMc http://www.newscientist.com/article/dn1422 1-australian-crocs-hit-by-cane-toad-waveof-death.html#.UiawBjasim4 What is another example of an exotic species that was introduced in Australia? Ahhh a cute bunny rabbit! 15 European rabbits first arrived in Australia with the First Fleet in 1788, but they only became a pest after 24 wild rabbits were released for hunting near Geelong in Victoria 150 years ago. By the 1920s, Australia's rabbit population had swelled to 10 billion. So in 1950 the biological control agent, Myxoma virus, was introduced to Australia's mainland. http://www.abc.net.au/science/articles/2009 /04/08/2538860.htm Are there examples of exotic species in Canada? To combat the reduced effectiveness of myxoma virus, calicivirus, or rabbit haemorrhagic disease (RHD), was released in Australia in 1995. 11 invasive species threatening Canadian habitats 16 From parasites to crabs and living slime affectionately dubbed "rock snot," invasive species can wreak havoc when introduced into a new habitat. 1. Asian carp Source: http://www.cbc.ca/news/technology/story/2012/02/23/f-invasive-species.html 2. European green crab 17 The European green crab preys on mussels, clams and other crabs, threatening shellfish stocks on the Atlantic coast. It's a naturally aggressive and territorial crab species, found near Prince Edward Island, Quebec's Magdalen Islands, Nova Scotia's Cape Breton Island and the waters off southern Newfoundland, where it was first discovered in 2007. According to Fisheries and Oceans Canada, unless controlled, the crab's impact will surely be felt in Newfoundland's ecosystem. And then there is…#3-8 18 Purple loosestrife Sea lamprey Zebra mussel Gypsy moth Emerald ash borer Round goby 9. Didymo deserves it’s own page! 19 (aka rock snot) And…10-11 20 Asian long-horned beetle Gypsy moth his beetle from China attacks hardwood trees such as maples. It first appeared in North America in 1996 in New York state. In Canada, it was first found in 2003 in an industrial park between Toronto and the city of Vaughan. Larvae of the gypsy moth are known to eat the leaves of about 300 plants, causing widespread damage. Task 21 What outcomes have we covered so far? 22 Section 4.2 Terrestrial and Aquatic Ecosystems Nelson Pages 94-100 Curricular Outcomes: 23 20–B1.1k Define and explain the interrelationship among species, population, community and ecosystem 20–B1.2k Explain how a terrestrial and an aquatic ecosystem supports a diversity of organisms through a variety of habitats and niches Curricular Outcomes: 24 20–B1.3k Identify biotic and abiotic characteristics and explain their influence in an aquatic and a terrestrial ecosystem in a local region 20–B1.4k Explain how limiting factors influence organism distribution and range 1. ABIOTIC FACTORS IN TERRESTRIAL ECOSYSTEMS 25 abiotic factors are the non-living components of an ecosystem affect the type and number of organisms that can live there Describe abiotic components that cause the two terrestrial ecosystems below? Canadian Biomes – Page 94 Edmonton TERRESTRIAL ECOSYSTEMS IN ALBERTA 1. TAIGA (BOREAL FOREST) ECOSYSTEMS Northern & Central AB forests Warm, wet summer; Cold, dry winter Dominated by CONIFERS: PINE trees, SPRUCE trees cone-bearing trees that have needles -Reduce water loss ( S.A., thick cuticle) -Pyramid shape of tree heavy snow weight Canopy (tree tops): find seed-eating birds, red & flying squirrels Forest Floor: find shade-loving plants (shrubs, ferns, mosses), moose, deer, bear, weasels, grouse, owls, etc. 2. MUSKEG ECOSYSTEM: More Northern Taiga (colder!) PERMAFROST Water never drains away… beneath soil (never melts!) Water soaks into the PEAT (decomposing organic matter) Forms the MUSKEG or BOG (swampy!) Very Acidic soil Find black spruce trees, mosses, lichens, caribou, mosquitoes! Very SLOW DECOMPOSITION Soil formation is very slow… damage to this ecosystem takes many years to repair… BOG MUMMY A bog body is a human cadaver that has been naturally mummified within a peat bog. 3. GRASSLAND (“Prairies”) Southern AB Nutrient-rich black earth Short-lived grasses provide large biomass for decomposition More sunlight, less precipitation limited diversity (no canopy, etc.) Find “grasses and grazers” (various grass species, bison, deer) rabbits, gophers, hawks, grasshoppers, etc. 4. DECIDUOUS FOREST ECOSYSTEM Central AB Between grassland and taiga biomes Dominated by deciduous (leavelosing) trees aspen poplar, balsam poplar & birch Rich, fertile soil (lots of “leaf litter”) MOST DIVERSITY! Canopy, understory, & forest floor Bears, moose (“browsers”), deer, weasels, woodpeckers, shrubs, etc. etc. See Fig 6 p.96 AQUATIC ECOSYSTEMS Water covers 2/3 of earth 97% is saltwater (oceans) Evaporation from oceans = freshwater (most in form of snow & ice on earth) ALBERTA aquatic ecosystems = ponds, rivers, and lakes ALBERTA LAKE ECOSYSTEMS Sketch Fig 7 page 99 LITTORAL ZONE extends from lakeshore to where plants are no longer rooted in the lake bottom Shallow, lots of sunlight Most productive part of lake - algae and plants performing photosynthesis Plants can be floating (algae), emergent (water lilies) or submerged (seaweed) LIMNETIC ZONE Area of open water where there is still enough sunlight for photosynthesis Plankton is food for consumers AUTOTROPHIC PLANKTON (tiny plants & algae) HETEROTROPHIC PLANKTON (tiny invertebrate animals) PROFUNDAL ZONE Deepest part of lake, no sunlight not found in ponds or shallow lakes Only nutrients = decaying matter (detritus) that falls from the limnetic zone Find lots of decomposers (bacteria), few bottomdwelling fish, & invertebrates LOW O2 LEVELS due to lack of plants and lots of decomposers Wow, what at catch! Wow, um already then! FYI – Random fact of the day - GIANT CATFISH ARE “BOTTOM FEEDERS” Section 4.3 -Factors Affecting Ecosystems 40 Factors Affecting Terrestrial Ecosystems Soil 1. Litter-upper layer of soil-decomposed plants Topsoil-under the Litter-small rocks mixed with humus (decaying matter) Subsoil-below Topsoil-mostly rock particles, very little organic matter Bedrock-layer beneath soil, composed of rock 4.3 Continue 41 Available Water 2. Amount of water will determine what can grow. Leaching is a problem, can dissolve nutrients and minerals and take them deep in the soil. Plants in these areas must have deep roots to be able to use these materials 4.3 Continue 42 Temperature 3. Plants and animals must be adapted to temperature. Hotter is not always better! But why? Sunlight 4. Plants need the sun for photosynthesis 4.3 Aquatic Ecosystems 43 Chemical Environment 1. Dissolved oxygen, organic material (decaying plants and animals) Dissolved minerals and pollutants Temperature/Sunlight 2. Oxygen dissolves better at certain temperatures Temperature is usually greater, the closer the water to the sunlight Aquatic Systems continue… 44 Water Pressure 3. Gets higher the lower you go 45 4.3 Aquatic Systems Continue Summer Lake Levels 46 4.3 – Aquatic Systems Seasonal Mixing This figure shows the change in populations of 2 populations of paramecia (single-celled organisms) placed in 3 different beakers. a) compare the growth of species 1 in Beaker A with the growth of species 2 in Beaker B b) What evidence suggests that the populations of paramecia affect each other? c) suggest a conclusion that can be drawn from the populations changes 48 4.4 LIMITS ON POPULATIONS AND COMMUNITIES IN ECOSYSTEMS Pages 108-112 Biotic Potential (p108) 49 Field mice can reproduce every 6 weeks and can have litters of 6 or more. A population of 20 mice could become 5120 mice in six months! What factors prevent a population explosion of mice? Biotic potential is the maximum number of offspring that a species could produce if resources are unlimited Regulated by four factors: birth potential (max #/birth), capacity for survival (# reach reproductive age), breeding frequency, and length of reproductive life (age of sexual maturity and # of fertile years) You afraid of a few mice? 50 http://www.youtube.com/watch?v=zWVw-j8eYSk Limiting Factors and Carrying capacity 51 Recall that limiting factors are factors that restrict or limit the number and types of organisms able to survive in a particular environment Limiting factors prevent populations from obtaining their biotic potential The carrying capacity is the maximum number of individuals that can be supported by an ecosystem At what level do the deer reach their CARRYING CAPACITY? ex. the small black spruce forest at Elk Island (the bog) can support 20 squirrels sketch growth curve here! Factors Affecting Population Change: Density Dependent vs. density Independent Factors Density Dependent factors brought on by pop. size may limit further growth and / or reduce pop. #’s • May cause reduced birth rate and increased emigration Biotic factors When populations are small, density dependent factors do not limit growth Examples include: disease, parasites, predation, starvation • Density Independent • any abiotic factors that will affect a pop., regardless of its size • Daily and seasonal temp. extremes • Natural disasters, including drought, floods, forest fires, etc. Competition: 2 Types - intERspecific competition (between 2 diffERent species) - intrAspecific (sAme species competing) Intraspecific Competition Interspecific Competition Tasks to be completed: 57 Read Section 4.4 in your Text – Pages 108-111 Complete the Section 4.4 Questions – Pages 111- 112 – 1-2, 5 4.5 CHANGES IN ECOSYSTEMS Collapsed permafrost block of coastal tundra on Alaska’s Arctic Coast. Pages 113-122 Nelson 58 CHANGES IN ECOSYSTEMS 1. TERRESTRIAL ECOSYSTEMS Forestry Practices: (Add your own notes such as pros and cons of each tecnique) “SLASH & BURN” (P113) Clear cutting in the Amazon Clear cutting in patches in Canada “Clear Cutting” “PRESCRIBED BURNS” ex. used at Elk Island to create grasslands for bison 2. AQUATIC ECOSYSTEMS EUTROPHICATION of lakes -oligotrophic to eutrophic (remember Fig 4 p.116) Classification of lakes by the nutrient input which also determines the primary producers. Oligotrophic lake: Nutrient-poor, photosynthesislimited, clear water, O2 rich. Eutrophic lake: Nutrient-rich, high photosynthesis, murky water, O2 poor. 63 Sketch Lakes here: 64 Oligotrophic lake: Eutrophic lake: POLLUTION of lakes -organic solid waste (sewage, food wastes) -disease organisms (“beaver fever”) -dissolved minerals (fertilizers) -thermal energy (decreases O2 levels) -organic compounds (oil, pesticides) Lake Wabamum Power Plant Retires (demo of stacks): http://www.youtube.co m/watch?v=RNpApbh 7Wcw An aerial image of Lake Wabamun from August 2005 shows the oil slick that killed 156 birds. INDICATORS OF WATER QUALITY BACTERIA COUNTS -ex. coliform bacteria from animal waste -can lead to beach closures! DISSOLVED OXYGEN -more O2 = more diversity of organisms -find more O2 in cold, less polluted lakes No Beach for you! 67 The blue-green algae that bloom in lakes and waterways produce a toxin that is harmful to humans — and this toxin, microcystin, is present in lakes in every Canadian province, a new study has found. Blue-green algae, or cyanobacteria, can kill fish, increase the cost of water treatment and devalue shoreline BIOLOGIST SANDRA COOK AND LIFEGUARD JULIEN CLERK-LAMALICE AT O'BRIEN BEACH ON MEACH properties. The algae also produce LAKE, CLOSED DUE TO BLUE-GREEN ALGAE. microcystin, a known potent liver toxin to humans and mammals that is classified as a possible human carcinogen. http://www.sunnewsnetwork.ca/sunnews/sciencetech/archives/2012/08/20120814093516.html pollution increases the natural eutrophication process of water. Why? Unnatural Eutrophication: a process in which nutrient runoff from agricultural lands or livestock operations causes photosynthetic organisms in ponds and lakes to multiply rapidly 68 Human-caused eutrophication wiped out fisheries in Lake Erie in the 1950s and 1960s •FYI - Dr. David Schindler is an ecologist who worked at the Experimental Lakes Project in northern Ontario –He performed several classic experiments on eutrophication that led to the ban on phosphates in detergents 69 David Schindler, Killam Memorial professor of ecology at the University of Alberta, holds a deformed white fish caught in Lake Athabasca, near Fort Chipewyan, during a Sept. 16 press conference in Edmonton. (Jason Franson/Canadian Press) 70 BIOLOGICAL O2 DEMAND (BOD) -measures how much O2 is needed by decomposers -more decomposers = greater BOD = less O2 dissolved in lake for fish, etc. Tasks to be completed: 72 Read Chapter 4.5 in your textbook – Pages 113-121 Make your own notes on: Forestry Practices – page 113 – 114 The effects of fire – page 115 Go through “Selling Water” –page 120-121 #1-5 Complete Section 4.5 Questions – Page 122 – #5 Chapter 4 Review: P130 #1-8 Section 4.3 Questions Page 107 #1-4, 7 73 1. The amount of organic matter in an ecosystem can increase through runoff from soil, surface waters, fertilizer use, release of sewage emissions, litter from plant material, animal wastes, and die-offs of plants and/or animals, etc. 2. It is possible to have two ecosystems with identical rainfall and temperature support different plants. For example, Europe and North America both have deciduous forest ecosystems with similar temperatures and rainfall. Both have tall trees, shrubs, ferns etc., but since they are in different geographic locations, the species of each plant type might be different. 3. The oxygen concentration in the hypolimnion is high initially due to spring turnover. The oxygen concentration gradually falls as the oxygen is consumed by bacteria that decompose dead plant and animal materials. In extreme situations, oxygen may be completely consumed. 74 4. The lower, cooler layers of water have no source of oxygen input, so it is gradually consumed. The surface layers receive more oxygen when wind and waves disturb the surface, allowing oxygen to dissolve. 7. Trout can exist only in cooler, oxygen-rich waters. They survive below the thermocline in lakes that stratify and remain high in oxygen, not in shallower, warmer waters. Catfish are always found close to the bottom since they are bottom feeders. They can live in shallow, warm waters and can also tolerate low oxygen levels. Neither of these situations can support trout Section 4.4 Questions – Page 111 #2-3, 5 75 2. (a) The carrying capacity is the maximum number of individuals in a population that the environment can sustain. If the supply of food in the winter months is a limiting factor (a factor that limits the carrying capacity), then providing seeds during winter months would increase the number of cedar waxwings and artificially raise the carrying capacity. (b) The increase in the number of falcons may be due to the banning of DDT. As well, the question suggests that the bird watchers seeing the falcons are also the people feeding the waxwings. The falcons are probably also attracted to the bird feeders, to eat the nice supply of cedar waxwings. 3. (a) Wolves prey on the moose population. With a declining wolf population, there will be less predation on the moose. Assuming that the cause of the wolf decline is not affecting the moose population, you would expect an increase in the moose population. (b) The wolf population will probably not decrease to zero because the increased moose population provides the remaining wolves with a plentiful supply of food. Assuming that humans are not the cause (hunting, habitat loss, introduction of a competitor or disease, climate change), you would expect the wolf population to recover. In a natural population, the size will fluctuate from year to year. There are many factors that affect population size, availability of prey, water, availability of mates, competition, disease, forest fire, and available space/habitat. Prior to Europeans settling in North America, the wolf survived for thousands (perhaps hundreds of thousands) of years. Eventually, all species go to extinction, but it is unlikely that the wolf population would go extinct in a few generations without the influence of humans. (c) The wolf population will increase again when conditions become favorable— when whatever conditions caused the decline have changed. For example, if the cause of the decline was a small moose population that the wolves rely on for food, then as soon as the moose population increases (due to less predation by smaller wolf numbers), the wolf population will recover and start increasing in numbers. (d) decrease in wolves → increase in moose → decrease in plant material → 76 decrease in moose → increase in plant material → increase in moose → increase in wolves 5. (a) Predator species C is the best controlling agent because it causes the only steady decline in the population of pine bark beetles. (b) The eggs of predator species D might be eaten by the pine bark beetle because the beetle population increases and the predator D population decreases. (c) The population of predator species A may be consistently lower than that of the pine bark beetle because the pine bark beetle somehow has a negative effect on the predator. Also, since each predator individual requires many prey individuals to survive, predator populations are usually smaller than prey populations. (d) If the population of predator species C exceeds its carrying capacity in the environment, its population would probably crash, whereas any surviving pine bark beetles would cause their population to rebound. 77 Section 4.5 P122 #4-5 78 4. (a) Over time, a lake decreases in depth and fills in with sediment. (b) Deeper lakes tend to be colder. Since water is most dense at 4 ºC, in deeper lakes, the water at the bottom would always be at or close to this temperature. Also, more of the water in a deep lake is in the profundal zone and receives no heat energy from the Sun to warm it up. (c) In warmer lakes, there are a greater number and variety of plants found in the littoral zone. (d) Cold, deep lakes have populations of trout and salmon in the layers with higher oxygen levels. Brown trout can tolerate less oxygen and are found where other species of trout cannot survive. Bass can also tolerate lower oxygen levels. Carp and catfish are especially tolerant of low oxygen levels. As the lake eutrophies, the trout and salmon will disappear first, followed by the brown trout, the bass, and, finally, the catfish and carp. (e) Turtles eat the plants that grow in the later stages (but not in the early stages) of an oligotrophic lake 5. (a) Nitrates and phosphates come from the sewage-treatment plant. (b) The highest level of eutrophication would be at B, where the nitrate and phosphate levels are highest. (c) The BOD increases from A to B because more organisms live at B. Some are decomposing organic wastes, whereas others are taking advantage of the increased nutrients. The organisms consume oxygen. (d) The BOD decreases from B to C because C has fewer nutrients and the oxygen is consumed mainly by decomposers. (e) If the sewage treatment plant were doing a good job, the drop in dissolved oxygen would not be as great. 79