1. Define The following Levels:
    Biosphere- Combined portion of the planet in which all of life exists includig land, water, and air

    Biome- group of ecosystems that have the same climate and similar dominant communities

    Ecosystem- a collection of all the organisms that live in a particular place combined with there physical environment

    Community- an assemlafe of different populations that live together in a defined area

    Population- a froup of individuals that belong to the same species and live in the same area

    Species- a group of organisms so similar to one another that they can breed and prduce fertile offspring
  2. Describe the basic approches to ecological research
    • Observing- simple or complex
    • Experimenting- set up arteficial environments in a lab to test hypotheses
    • Model building- a way to study/interpret/explain very complex phenomena and are tested with real life data.
  3. what percent of all the sun's energy is actually used by plants?
  4. Of the energy that a plant gets, how much is stored in the plant?
  5. Describe the different levels of consumers
    • Primary consumers- eat plants
    • Secondary- feed on primary
    • Tertiary - feed on secondary
  6. What is biomass?
    The total mass of all organisms in a trophic level
  7. Describe the three Ecological pyramids
    Energy Pyramid- Shows the relative amount of energy available at each trophic level. At each new level there is 10% of the energy of the last level

    Biomass Pyramid- Represents the amount of loving organic matter at each trophic level

    Pyramid of numbers- Shows the relative number of individual organisms at each trophic level.
  8. Why do all organisms require nitrogen?
    • to build protiens and genetic material.
    • free nitrogen makes up 78% of our air!
  9. Define Nitrogen fixation
    Bacteria that live on the roots of some plants capture nitrogen gas and fix (glue) the nitrogen into chemical compounds
  10. plant and animal remains and other dead matter are collectively called______
  11. what does a food web link together?
    all the food chains in an ecosystem
  12. Why is carbon especially important to living systems?
    It's the key ingredient in all living organisms
  13. what is dentrification
    other soil bacteria convert nitrates into nitrogen gas.
  14. what is the main resevoir of nitrogen in the biosphere?
    the atmosphere
  15. when is a substance called a limiting nutrient?
    when it is scarce or cycles very slowly
  16. what is symbiosis?
    any relation in which 2 species live closely together
  17. describe the following relationships:
    • Mutualism- both species benefit
    • commensalism- one benefits, the other is not harmed
    • Parasitism- one lives on the other and harms it
  18. what is ecological succession?
    series of predictable changes that occurs in a community over time
  19. what is primary succession?
    succession that occurs on surfaces where no soil exists(volcanic islands)
  20. The mechanism of population control in which a population is regulated by predation is called a ____
    Predator-prey relationship......=GOOD!
  21. Give exaples of desity-independent limiting factors.
    weather, natural disaster, seasonal cycles, certain human activities
  22. what is biodiversity?
    the sum total of the genetically based variety of all organisms in the biosphere (variety)
  23. Define Ecosystem diversity
    the variety of habitats, communities, and ecological prcesses in the living world
  24. define species diversity
    the number of different species in the biosphere
  25. define genetic diversity
    total of all the different forms of genetic ingormation carried by all organisms living on Earth today
  26. Why is biodiversity one of Earth's greatest natural resources?
    species of many kinds have provided us with foods, industrial producs, and medicines
  27. the process of splitting a habitat into small pieces is called ____
    habitat fragmentation
  28. what is biological magnification?
    the concentration of a harmful substance increasing in organisms at higher trophic levels in a food chain or web
  29. why do invasice species roproduce rapidly and increase their populations?
    their new habitat lacks parasites and predators that control ther population "back home"
Card Set
9th Grade Ecology Test