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Exam #3 Review Honors Biology

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  • Why do farmers add fertilizers to their crops?
    it contains usable nitrogen and phosphorus that plants can use to grow
  • Why should farmers be concerned about unused nitrates, from fertilizer use, contaminating surface water and groundwater supplies?
    Excessive amounts of nutrients speed up the eutrophication process
  • If an ecosystem contained grasses, grasshoppers, birds, and snakes, what about how much energy would the bird receive?
    1%
  • Give an example of density dependent limiting factors and density independent limiting factors.
    any acceptable answer
  • Where does the original source of energy come from in an ecosystem?
    the sun
  • Describe the difference between exponential growth and logistic growth.
    exponential - growth rate stays the same over time and has no limit due to unlimited resources; logistic - limited by limited resources
  • Why are decomposers in soils and water important to ecosystems?
    they recycle nutrients
  • Which cycle does not have an atmospheric component?
    phosphorus
  • How does transpiration play a role in the water cycle?
    it returns water vapor to the atmosphere from a plant
  • What process removes carbon from the atmosphere?
    photosynthesis
  • As resources in a population become less available, the population is reaching___.
    its carrying capacity
  • How does cellular respiration in plants and animals used in the carbon cycle?
    returns carbon dioxide to the atmosphere
  • Why do most ecological pyramids only go up to the tertiary consumer level?
    decrease in energy
  • What would happen if the decomposers were removed?
    nutrients would not be returned to the soil
  • Which process involves the capture and conversion of nitrogen gas into a useable form by plants?
    nitrogen fixation
  • Which of the following would be a limiting factor for a population? (decrease in competition, fewer predators, reduction of disease, loss of habitat)?
    loss of habitat
  • What is a factor that would cause a decrease in population growth?
    Any acceptable answer (deaths, disease, emigration, etc.)
  • What is a factor that can increase the growth of the population?
    any acceptable answer (births, immigration, abundant resources, etc.)
  • Energy is transferred between trophic levels in a food pyramid. If 1,250 joules of energy is in the producers how much energy would be transferred to the tertiary consumers?
    1.25 Joules
  • How is the movement of matter through the biosphere different from the movement of energy?
    energy - flows in one direction (producers to top consumer; matter - is recycled within and between ecosystems through a series of events
  • How could percolation lead to contaminated ground water?
    pulls toxins from the grounds surface down through the soil
  • Where on the graph would indicate where the hare reached its carrying capacity?
    student points at correct spot on graph
  • What type of organisms are responsible for "fixing" nitrogen or helping to put it in a form so other living things can use it?
    bacteria
  • Give 2 reasons why nutrient cycles are important. Be specific in what they are used for in terms of macromolecules.
    CHONP (carbs, lipids, proteins, nucleic acids)
  • A variable that influences an individuals probability of survival and reproduction in a manner that depends on the size of the population
    density-dependent limiting factor
  • What do the arrows represent in the food chain?
    the flow of energy
  • Describe the impact of all the grass being killed by a herbicide.
    all other trophic levels would see a decrease
  • Why are nutrient cycles described as being a closed loop?
    elements pass between organisms and physical spaces within the biosphere
  • A community in which hawks and snakes consume only moles is being observed. If the number of snakes increases, what would be some possible impacts to this community?
    any acceptable answer (moles would decrease, more competition)
  • What trophic level are the owls in?
    4th
  • What is the term for something that controls the growth or size of a population?
    limiting factor