Ecology 1


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  • Ecology 1

    1. 1. Ecology 1: Ecosystems
    2. 2. Levels of Organization <ul><li>Organism </li></ul><ul><ul><ul><li>Ex. an elephant </li></ul></ul></ul><ul><li>Population </li></ul><ul><ul><li>A group of individuals in the same species, living and interacting in one area </li></ul></ul><ul><ul><ul><li>Ex. a herd of elephants in the Serengeti </li></ul></ul></ul><ul><li>Community </li></ul><ul><ul><li>Multiple populations interacting in one area </li></ul></ul><ul><ul><ul><li>Ex. grazing antelope, elephants and giraffes in the Serengeti </li></ul></ul></ul><ul><li>Ecosystem </li></ul><ul><ul><li>All populations in one area interacting with each other and their non-living environment. </li></ul></ul><ul><ul><ul><li>Ex. the Serengeti (all organisms plus climate, nutrients, etc.) </li></ul></ul></ul>
    3. 3. Levels of Organization <ul><li>Biosphere </li></ul><ul><ul><li>All areas of the earth from the ocean depths to the atmosphere that support life. </li></ul></ul>
    4. 4. Ecological roles <ul><li>Autotrophs - Producer </li></ul><ul><ul><ul><li>makes own food (through photosynthesis or chemosynthesis) </li></ul></ul></ul><ul><li>Heterotrophs - Consumer </li></ul><ul><ul><ul><li>must eat other organisms for food; </li></ul></ul></ul><ul><ul><ul><li>primary (mouse), secondary (fox), tertiary (bobcat) </li></ul></ul></ul><ul><ul><li>Herbivore (eats plants) Carnivore (eats meat) Omnivore (eats both) </li></ul></ul><ul><ul><li>Detritivore </li></ul></ul><ul><ul><ul><li>Organisms that feed on animals remains and dead material (crabs, earthworms) </li></ul></ul></ul><ul><ul><li>Decomposer </li></ul></ul><ul><ul><ul><li>An organism (ex. fungi or bacteria) that completes the final breakdown of materials in an ecosystem </li></ul></ul></ul><ul><ul><ul><li>End of 3.1 </li></ul></ul></ul>
    5. 5. How does energy enter the ecosystem? <ul><ul><li>Energy hits the earth in the form of sunlight </li></ul></ul><ul><ul><li>Autotrophs convert sunlight (or chemical) energy into organic molecules </li></ul></ul><ul><ul><li>Less than 1% of the sun’s energy is converted into organic material </li></ul></ul><ul><ul><li>Eventually all energy is lost back to the atmosphere as heat. </li></ul></ul>
    6. 6. How does energy move through an ecosystem? <ul><li>Energy trapped in autotrophs ( producers ) then gets transferred to heterotrophs ( consumers ) as one organism eats another </li></ul><ul><li>The easiest way to show this is by using a food chain, food web, or food pyramid. </li></ul><ul><li>Food chain – series of steps in which organisms transfer energy by eating and being eaten. </li></ul>
    7. 7. Food Web links all ecosystems in a food chain together
    8. 8. Food Pyramids <ul><li>A food pyramid is designed to show the organisms in an ecosystem, grouped by their feeding position or trophic level (1 st =prod, 2 nd =herbivores, etc) </li></ul><ul><li>Both food chains and food pyramids show that only 10% of the energy at one trophic level makes it to the next trophic level (from the 2 nd law of thermodynamics). </li></ul>
    9. 9. Primary Productivity <ul><li>Therefore, the ecosystems with the most productive producers have the most levels (ex. rain forest) </li></ul><ul><ul><li>In most cases, there are only 3-4 levels. </li></ul></ul><ul><ul><li>End of 3.2 </li></ul></ul><ul><li>The rate at which new organic material is created in an ecosystem by producers is called the Primary Productivity </li></ul><ul><li>The more energy entering the food chain (from producers), the more that can pass up through the levels (only 10% moves up at each level), and as result, the more levels there can be. </li></ul>
    10. 10. How do nutrients cycle? <ul><li>Energy follows a ONE-WAY path </li></ul><ul><ul><li>Sun  living organisms  heat  atmosphere </li></ul></ul><ul><li>Matter CYCLES through living organisms endlessly </li></ul><ul><li>Biogeochemical cycles </li></ul><ul><ul><li>Water </li></ul></ul><ul><ul><li>Carbon and Oxygen </li></ul></ul><ul><ul><li>Nitrogen </li></ul></ul>
    11. 11. Water Cycle
    12. 12. Carbon and Oxygen Cycle
    13. 13. Nitrogen Cycle
    14. 14. Niches <ul><li>Niches vs Habitats </li></ul><ul><ul><li>A habitat is the location where a species lives . </li></ul></ul><ul><ul><ul><li>Ex. tall grassland/prairie </li></ul></ul></ul><ul><ul><li>A niche includes all of the species’ requirements plus its role in the ecosystem. It is determined by all the the abiotic and biotic factors relevant to the species. </li></ul></ul><ul><ul><ul><li>Ex. Top predator in prairie areas where gophers live, and the temperature is never below freezing. </li></ul></ul></ul>
    15. 15. Niche differences <ul><li>Organisms can be identified as either </li></ul><ul><ul><li>Generalists </li></ul></ul><ul><ul><ul><li>Organisms with a broad niche </li></ul></ul></ul><ul><ul><ul><li>Eat lots of types of food </li></ul></ul></ul><ul><ul><ul><li>Live in many types of environments </li></ul></ul></ul><ul><ul><ul><li>Ex. house mice </li></ul></ul></ul><ul><ul><li>Specialists </li></ul></ul><ul><ul><ul><li>Organisms with a narrow niche </li></ul></ul></ul><ul><ul><ul><li>Eat a narrow range of food items </li></ul></ul></ul><ul><ul><ul><li>Live in few, specific types of habitats </li></ul></ul></ul><ul><ul><ul><li>Ex. panda bear </li></ul></ul></ul>
    16. 16. Mutualism <ul><li>Mutualism occurs when both species benefit </li></ul><ul><ul><li>Rhinos and oxpeckers </li></ul></ul><ul><ul><li>trees and mycorrhizae, </li></ul></ul><ul><ul><li>ants and acacia </li></ul></ul><ul><ul><li>Termites and protist </li></ul></ul><ul><ul><li>Pollination (Yucca and yucca moth) </li></ul></ul>
    17. 17. Parasitism <ul><ul><li>one organism feeds on/lives on another species </li></ul></ul><ul><ul><li>typically host is bigger than parasite </li></ul></ul><ul><ul><li>parasites usually do not kill host (weaken them) </li></ul></ul><ul><ul><li>parasites need host for food, shelter, etc. </li></ul></ul><ul><ul><li>ex. fleas on dog, tapeworm in human, mistletoe, lamprey </li></ul></ul>
    18. 18. Commensalism <ul><li>Commensalism occurs when one species benefits, and the other neither benefits, or is harmed </li></ul><ul><li>examples: </li></ul><ul><ul><li>clownfish and anemones </li></ul></ul><ul><ul><li>epiphytes and trees </li></ul></ul><ul><ul><li>Cattle egrets and ungulates </li></ul></ul>
    19. 19. Predation <ul><li>Predation - one organism feeds upon the other </li></ul><ul><ul><li>predator usually bigger than prey </li></ul></ul><ul><ul><li>ex. lion eating zebra </li></ul></ul>
    20. 20. Prey Strategies
    21. 21. Competition <ul><li>When two species use the same resources, they are said to compete and their interaction = competition . </li></ul><ul><ul><li>ex. lions and hyenas compete for food in Africa </li></ul></ul><ul><li>Competition does not necessarily involve contact; interaction may be only by means of effects on the resources. </li></ul><ul><li>No two organisms can occupy exactly the same niche at the same time </li></ul>
    22. 22. What determines where species can live? <ul><li>All species have requirements for many factors/conditions. </li></ul><ul><ul><li>Abiotic factors – non-living factors; ex. temperature, precipitation, pH </li></ul></ul><ul><ul><li>Biotic factors – other species; ex. prey species, competing species </li></ul></ul><ul><li>For each of these factors, species exhibit a range of tolerance . </li></ul><ul><ul><li>For example, a fish species may only be found within a pH range of 4.5 to 6 in lakes. </li></ul></ul>
    23. 23. Biomes <ul><li>A major terrestrial community that is found in different areas with similar climate is called a biome . A biome’s structure and appearance are similar throughout its distribution. </li></ul><ul><li>The world’s biomes are tropical rain forest, tropical dry forest, temperate woodland and shrubland (Chaparral), temperate deciduous forest, boreal/coniferous forest (taiga), desert, temperate grassland, tropical grassland (savanna), and tundra. </li></ul>
    24. 24. Biome distribution
    25. 25. Freshwater Habitats <ul><li>These habitats are distinct from both marine and terrestrial habitats and are very limited in area. </li></ul><ul><ul><li>make up about 2% of earth’s surface </li></ul></ul><ul><ul><li>can be divided into </li></ul></ul><ul><ul><ul><li>Flowing water (rivers) standing water (ponds and lakes) and wetlands (seasonal coverage) </li></ul></ul></ul>
    26. 26. Freshwater Habitats <ul><li>Estuaries </li></ul><ul><ul><li>These are very important for </li></ul></ul><ul><ul><ul><li>Breeding grounds for fish </li></ul></ul></ul><ul><ul><ul><li>Filtering water </li></ul></ul></ul><ul><ul><li>Very productive ecosystems! </li></ul></ul><ul><ul><li>Disappearing fast (flat land near the ocean) </li></ul></ul>
    27. 27. Ocean <ul><li>75% of earth’s surface </li></ul><ul><li>Continental shelf - shallow ocean waters - smallest area; large number of species (kelp forests) </li></ul><ul><ul><li>Intertidal zones </li></ul></ul><ul><ul><ul><li>Along our coast </li></ul></ul></ul><ul><ul><ul><li>Species can tolerate being in and out of water </li></ul></ul></ul><ul><ul><ul><li>Sea stars, algae, sea anemones </li></ul></ul></ul><ul><ul><li>Coral Reefs </li></ul></ul><ul><ul><ul><li>The “rain forests” of the ocean </li></ul></ul></ul><ul><ul><ul><li>High diversity </li></ul></ul></ul><ul><ul><ul><li>In tropical waters </li></ul></ul></ul>
    28. 28. Ocean <ul><li>open sea surface - contains plankton (free-floating microscopic organisms), bacteria, algae, fish larvae; responsible for 40% of world’s photosynthesis </li></ul><ul><li>Benthic zone - deep sea waters - below 1000’ feet animals adapted to dark; some blind/bioluminescent </li></ul>
    29. 29. What happens when ecosystems are disturbed? <ul><li>When a disturbance impacts an ecosystem, it recovers through a process known as succession. </li></ul><ul><li>Succession on newly formed habitat is called primary succession . </li></ul><ul><ul><li>No remaining organisms or soil </li></ul></ul><ul><ul><li>Examples, lava flow, sand dune, glacier retreat </li></ul></ul><ul><ul><li>It can take 1000+ years from sand dune to forest. </li></ul></ul>