Ecology

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Ecology

  1. 1. Ecology• Biosphere – contains combine portions of the planet in which all life exists; abiotic and biotic• Relationships within the biosphere, ecologists ask questions about events and organisms that range in complexity from a single individual to the entire biosphere• Species – populations – communities – ecosystem - biome
  2. 2. methodologies• Regardless of the tools they use, scientists conduct modern ecological research using 3 basic methods;• observing, experimenting, modeling
  3. 3. Energy Flow• Sunlight is the main source of energy for life on earth - photosynthesis• Some life forms rely on the energy stored in inorganic chemical compounds (no carbon) chemosysthesis• Energy flows through an ecosystem in one direction, from the sun/inorganic compounds to autotrophs and heterotrophs (food chains)
  4. 4. Cont.• Only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level
  5. 5. Cycles of Matter• Matter is recycled within and between ecosystems• Biogeochemical cycles: matter is not used up, it is transformed• Water cycle – evaporation, condensation, precipitation• Nutrient cycle – organisms need nutrients to build tissue and carry out essential life functions
  6. 6. Cont.• Carbon cycle – key ingredient of living tissue• Nitrogen cycle – required to make amino acids• Phosphorus cycle – forms DNA and RNA• Nutrient limitations – scares or cycles slowly
  7. 7. Ecosystems• Biotic – biological factors• Abiotic – physical factors• Both determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives• Niche – occupation
  8. 8. Interaction• Community interaction, such as, competition, predation, and various forms of symbiosis can powerfully affect an ecosystem• Ecosystems are constantly changing in response to natural and human disturbances.• As an ecosystem changes, older inhabitants gradually die out, new organisms move in, causing further changes in the community
  9. 9. Cont.• Primary succession – no soil exists• Secondary succession – changes existing community without removing soil• Pioneer species – the first to arrive (other than soil)
  10. 10. Biomes• Tropical rain forest• Tropical dry forest• Tropical savanna• Temperate grasslands• Desert• Temperate woodlands and shrubland• Temperate forest• NW coniferous forest• Boreal forest (tiaga)• Tundra• Mountains and ice caps
  11. 11. Cont.• Each biome has a characteristic climate and community of organisms which include but are not limited to:• Abiotic factors• Dominant plants• Dominant wildlife• Geographic distribution
  12. 12. Aquatic Ecosystems• Aquatic ecosystems are determined primarily by the depth, flow, temperature and chemistry of the overlying water• Freshwater; divided into two main types; flowing water and standing water• Flowing water-river, streams, creeks, and brooks• Standing water – lakes and ponds
  13. 13. Cont.• Plankton – tiny free floating organisms (food)• Phytoplankton – single celled algae supported by nutrients in the water and form the base of aquatic food webs• Freshwater wetlands – bogs, marshes, swamps (fresh or salt water)• Estuaries – rivers meet sea
  14. 14. Marine Ecosystems• Photic – where photosynthesis takes place, limited to first 200m• Aphotic – permanently dark, below 200m• Marine biologist divide the ocean into zones based on the depth and distance from shore; intertidal, coastal ocean, open ocean
  15. 15. Cont.• Intertidal – area where tides changes• Coastal oceans – low tide mark to continental shelf (coral reefs)• Open ocean – edge of continental shelf outward, largest marine zone, covers 90% of ocean• Benthic – sea floor
  16. 16. Populations• Geographic distribution, density, growth rate• 3 factors can affect population size; births, deaths, and immigration/emigration• Exponential growth – reproduction at a constant rate• Under ideal conditions with unlimited resources, a population will grow exponentially
  17. 17. Cont.• Logistic growth – when populations growth slows or stops following a period of exponential growth• As resources become less available, the growth of a population slows or stops• Carrying capacity – largest number of individuals that an environment can hold

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