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Bio 100 Chapter 38

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  • 1. Chapter 38 Community and Ecosystem Ecology Lecture OutlineCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 2. Ridding the World of Waste http://www.youtube.com/watch?v=I1RHmSm36aE
  • 3. 38.1 Competition can lead to resource partitioning Competition is rivalry between populations for the same resources, such as light, space, nutrients, or mates  Competitive Exclusion Principle – no two species can occupy the same niche at the same time  Ecological niche – the role organism plays in its community, including its habitat (where the organism lives) and its interactions with other organisms and the environment  Resource partitioning – decreases competition between the two species 38-3
  • 4. Figure 38.1A Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Competition only P.aurelia grown occurs between separatelyPopulation two species of Density Paramecium when they are grown together P.caudatum grown separately When one speciesPopulation fed on the bottom Density and the other fed on suspended food, resource partitioning Both species occurred andPopulation grown together Density competition decreased Time 38-4
  • 5. Figure 38.1C Niche specialization occurs among five species of coexisting warblers Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cape May warbler Black-throated greenwarbler Bay-breasted warbler Blackburnian warbler Yellow-rumped warbler 38-5
  • 6. 38.2 Predator-prey interactions affect both populations Predation occurs when one organism (the predator) feeds on another (the prey) Predator – Prey interactions affect both populations  Numbers of one species dictates numbers of the other species 38-6
  • 7. Figure 38.2A Predator-prey interaction between a snowshoe hare and a lynx Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 140 hare lynx 120 100Number (thousands) 80 60 40 20 1845 1855 1865 1875 1885 1895 1905 1915 1925 1935 © Alan Carey/PhotoResearchers, Inc. 38-7
  • 8. Prey Defenses Prey Defenses  Camouflage – ability to blend into the background  http://www.youtube.com/watch?v=3WHUTL4fujo  Warning coloration tells the predator that the prey is potentially dangerous  Mimicry – when one species resembles another that possesses a defense  Batesian mimicry-a mimic lacks the defense of the organism it resembles  Mullerian mimicry-species have the same defense and resemble each other 38-8
  • 9. Figure 38.2B Antipredator defenses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Camouflage © Gustav Verderber/Visuals Unlimited 38-9
  • 10. Figure 38.2B Antipredator defenses (Cont.) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Warning coloration © Zig Leszczynski/Animals Animals 38-10
  • 11.  Viceroy Monarch
  • 12. Figure 38.2C Mimicry: All of these insects have the same coloration Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. flower fly longhorn beetle bumble bee yellow jacket (flower fly,longhorn beetle, yellow jacket): © Edward S. Ross; (bumblebee): © James H.Robinson/Photo Researchers, Inc. 38-15
  • 13. Parasitism Parasitism – a parasite infects a host A symbiotic relationship – at least one of the species is dependent on the other 38-16
  • 14. 38-17
  • 15. Commensalism Commensalism is a symbiotic relationship between two species in which one species is benefited and the other is neither benefited nor harmed  Example: Spanish moss grow in the branches of trees, where they receive light, but they take no nourishment from the trees 38-18
  • 16. Figure 38.4 A clownfish living among a sea anemone’s tentacles 38-19
  • 17. Mutualism Mutualism – symbiotic relationship in which both members benefit  Example: Bacteria in the human intestinal tract acquire food, but they provide us with vitamins Relationship between plants and their pollinators is a good example of mutualism Mycorrhizae & Lichens 38-20
  • 18. Figure 38.5BCleaning symbiosis occurs when small fish clean large fish Cleaning symbiosis – symbiotic relationship in which crustaceans, fish, and birds act as cleaners for a variety of vertebrate clients Large fish in coral reefs line up at cleaning stations and wait their turn to be cleaned by small fish that even enter the mouths of the large fish 38-21
  • 19. Primary & Secondary Succession Ecological Succession – series of species replacements in a community following a disturbance (flood, tornado, volcanic eruption, fire, clear-cutting forest)  Primary succession occurs in areas where no soil is present. Can take thousands of years.  Secondary succession begins in areas where soil is present. Much shorter time span than primary succession. 38-22
  • 20. Figure 38.6A Primary succession begins on areas of bare rock. Secondary succession begins at the grass stage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.rock lichens/mosses grass low shru b high shru b shrub-tree low tree high tree primary succession secondary succession 38-23
  • 21. 38.7 Ecosystems have biotic and abiotic componentsAbiotic (nonliving) components:  Sunlight, inorganic nutrients, type of soil, water, temperature, windBiotic (living) components:  Producers, consumers, scavengers (detritus feeders), decomposers 38-24
  • 22. Autotrophs Biotic Components of an Ecosystem  Autotrophs  Called producers because they produce food  Photoautotrophs, also called photosynthetic organisms, produce most of the organic nutrients for the biosphere  Exs: Algae, green plants 38-25
  • 23. Heterotrophs & Decomposers Heterotrophs need a preformed source of organic nutrients  Called consumers because they consume food  Herbivores are animals that graze directly on plants or algae  Carnivores feed on other animals  Omnivores feed on both plants & animals  Scavengers (detritus feeders) feed on the dead remains of animals and plants that have recently begun to decompose  Detritus refers to organic remains in the water and soil that are in the final stages of decomposition  Bacteria and fungi, including mushrooms, are the decomposers that use their digestive secretions to chemically break down dead organic matter 38-26
  • 24. Figure 38.8A Energy flow and chemical cycling in an ecosystem Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. solar energy heat producers consumers inorganic nutrient pool heat energy heat decomposers 38-27 nutrients
  • 25. Figure 38.8B Energy balances for an herbivore Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Heat to environment Energy to growth and reproduction carnivores Energy to detritus feeders 38-28 © George D. Lepp/Photo Researchers, Inc.
  • 26. Food Webs & Food Chains Food web, a diagram that describes trophic (feeding) relationships, common in nature Trophic Levels  Diagram that shows a single path of energy flow in an ecosystem are called Food Chain (rare in nature)  Trophic level is composed of organisms that occupy the same position within a food web or chain 38-29
  • 27. Figure 38.9 Grazing food web (top) and detrital food web (bottom) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Autotrophs Herbivores/Omnivores Carnivores owls nuts 4 birds hawks 1 2 leaf-eating insects deer 3 foxes 5 leaves 3 chipmunks rabbits skunks detritus snakes 3 mice mice death death death 38-30 fungi and bacteria in detritus invertebrates carnivorous invertebrates salamanders shrews
  • 28. 38.10 Ecological pyramids are based on trophic levels Ecological pyramid  10% rule – only about 10% of the energy of one trophic level is available to the next trophic level because of energy loss 38-31
  • 29. Figure 38.10 This ecological pyramid based on thebiomass content of bog populations could also be used to represent an energy pyramid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. top carnivores 1.5 g/m2 carnivores 11g/m2 herbivores 37g/m2 autotrophs 809 g/m2 38-32
  • 30. 38.12 The phosphorus cycle Phosphorus  On land, the very slow weathering of rocks places phosphate ions in the soil  Some of these become available to plants, which use phosphate to make ATP, and nucleotides that become DNA and RNA Human Activities and the Phosphorus Cycle  Human beings boost the supply of phosphate by mining phosphate ores for producing fertilizer and detergents  Results in eutrophication (overenrichment) of waterways 38-33
  • 31. Figure 38.12 The phosphorus cycle
  • 32. 38.13 The nitrogen cycle Ammonium (NH4+) Formation and Use  Nitrogen fixation occurs when nitrogen gas (N2) is converted to ammonium (NH4+), a form plants can use  Cyanobacteria and bacteria living on some roots can fix atmospheric nitrogen Formation of Nitrogen Gas  Denitrification is the conversion of nitrate back to nitrogen gas, which then enters the atmosphere  Denitrifying bacteria living in the anaerobic mud of lakes, bogs, and estuaries carry out this process as a part of their own metabolism 38-35
  • 33. 38.13 The nitrogen cycle is gaseous Human Activities and the Nitrogen Cycle  Humans significantly increase transfer rates in nitrogen cycle by producing fertilizers from N2  Nearly doubles the fixation rate  Fertilizer, which also contains phosphate, runs off into lakes and rivers and results in an overgrowth of algae and rooted aquatic plants  Acid deposition occurs because nitrogen oxides (NOx) and sulfur dioxide (SO2) enter the atmosphere from the burning of fossil fuels  Combine with water vapor to form acids that eventually return to the Earth 38-36
  • 34. Figure 38.13 The nitrogen cycle
  • 35. 38.14 The carbon cycle Human Activities & the Carbon Cycle  More CO2 is being deposited in the atmosphere than is being removed due to burning of fossil fuels and destruction of forests to make way for farmland  Greenhouse gas – allows solar radiation to pass through but hinder the escape of heat back into space, called the greenhouse effect 38-38
  • 36. Figure 38.14 The carbon cycle
  • 37. Connecting the Concepts: Chapter 38 Competition leads to resource partitioning Prey use various defenses against predators 3 examples of symbiotic relationships Primary vs. Secondary Ecological Succession Trophic levels exist within food chains & food webs (10% energy conservation between levels) Nutrients cycle (Phosphorous, Nitrogen & Carbon) 38-40