ACCELERATED BIOLOGY                                                      ROOM COPY
                         WORKSHEET 2-2 : INTERACTIONS
1. Which of the following abiotic factors seems to be the main limiting factor
       controlling the life present in the biomes listed below.
                 (Abiotic factors -> light // temperature // water // oxygen // minerals)
       a) Antartica b) mid-ocean c) desert d) on a rock surface e) deep in the soil

2. A: If a volcano creates a new island in the middle of the ocean, life forms will evolve
            through a series of changes called (primary // secondary) succession.
    B: If a farmer quits farming a field, life forms will evolve through a series of changes
            called (primary // secondary) succession.

3. Succession consists of a series of gradual changes through which life appears in a
        newly formed section of land. Each of the steps of succession leading to the
        development of a maple woodland is listed below, but is out of order. Place these
        steps of succession in their proper order.
     Pine woodland // Grass community // Maple woodland // Shrub community // Birch & Oak woodland

4. A: Food chains and food webs are simply diagrams showing the flow of ................
            from one organism to another.
    B: Use the following food chain to answer the questions below. Remember that
            each step in the food chain is considered another trophic level.
                      GRASS -> GRASSHOPPER -> FROG -> SNAKE
            1: Which trophic level has the most energy available to it?
            2: Which trophic level must begin each food chain?
            3: Redraw the food chain above into a food web with at least 10 organisms in
                    it.

5. According to the Competitive Exclusion theory animals cannot share the same
        resource while living in the same habitat. In the grasslands of Africa, many
        species of animals, such as zebras, wildebeests, and springboks, coexist in the
        same area though they all eat plants. Explain this seeming paradox of
        competitors living in harmony in the same area.

6. Imagine you live near a forest that has 10,000,000 pounds of photosynthetic
        biomass (all living plants).
                        [Questions A & B require calculations -> show all math]
    A: How much net plant production is available for herbivores in this forest? (in
            pounds)
    B: How much energy is available for the carnivores in this forest? (in pounds)
    C: Much of the plant matter produced by the forest is never consumed, but does
            eventually die. What happens to this plant matter that dies?
    D: The forest is constantly gaining and losing energy.
            1: How does new energy enter the forest?
            2: How does used energy leave the forest?
7. Many biogeochemicals are essential for all living things, and are therefore recycled
        through various trophic levels (ie. producers, consumers, decomposers). Four
        common cycles are: Water cycle, Phosphorus cycle, Nitrogen cycle, and
        Carbon-Oxygen cycle.
    A: Which of these cycles loses some of its materials into the deep ocean, and
            therefore is not a perfect cycle (ie. new chemicals always entering cycle
            through erosion)?
    B: Which of these cycles cannot begin without bacteria?
    C: Which of these cycles has its chemicals perfectly cycling between plants and
            animals (ie. each exactly undoes the work of the other)?
    D: Which cycle requires little to no input from living things?

8. Some animals have become strictly herbivores (plants) or strictly carnivores (meat),
        while other animals have become omnivores (eat both).
    A: What might be an advantage of developing a specialized herbivore or carnivore
            diet?
    B: What might be an advantage of developing an omnivore diet?

9. Which of the following statements is true and which is false?
    A: As a population of plants or animals nears its carrying capacity for a certain area
            density-dependent factors begin to play a greater role.
    B: A strong sign of a healthy biome is one in which the majority of its plant and
            animal species have reached their biotic potential.
    C: One reason for mankinds success in populating much of the earth is our control
            over density-independent factors around us.
    D: Disease is an example of a density-dependent factor.
    E: In a healthy population natality should approximately equal mortality.

10. Which of the following examples demonstrate intrinsic control between organisms.
        (Answer Yes or No)
           A: grasshopper & grass                      B: frogs & oak trees
           C: squirrels & dandelions                    D: honey bees & flowers

11. Competition between animals can come in two forms, intraspecific and
         interspecific.
    A: Each of the following situations best demonstrates which of these two forms of
            competition?
            1: male rams banging heads to determine control of a herd of female sheep
            2: an opossum eating the apples in an apple tree before any birds could get
                 them
            3: an anteater eating all the ants in an anthill leaving none for spiders located
                 nearby
            4: the largest lion mating with all the females of the pride
    B: Which form of competition can:
            1: slowly cause a change in a species (appearance, behavior, etc)
            2: slowly cause a species to become extinct
    C: Complex behaviors are often the result of these two forms of competition. Which
            form of competition might have produced these behaviors?
            1: long migrations                                  2: specialized mating habits

12. A: Which of the following types of rhythms seems to have the greatest impact on
             humans? Explain.
                   (Circadian rhythms // Annual reproductive cycles // Annual behaviors)
      B: What is the evolutionary advantage to an animal to have a specific reproductive
             cycle?
      C: Hibernation and estivation are evolutionary adaptations to what extreme factor
             in the environment of some animals?
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Critical Thinking Questions:
13. Environmental conditions are not the same in the oceans as they are on the land.
    A: Would abiotic factors be more stable in the oceans or on the land? WHY?
    B: List two abiotic factors that might have made it easier for life to begin in the
            oceans rather than on land.

14. Ecologists concerned with the shortage of food in the world suggest that people
            "eat lower on the food chain".
    A: Are they encouraging people to eat more meat or more grains? Explain.
    B: Concerning the flow of energy in the biosphere, explain why this practice might
            help feed more people.

15. A: Which of the following environments can support more numbers and types of
            life? Explain your choice.
            (a corn field // a field left unused for 5 years // a native deciduous forest // an apple orchid)
     B: Could a farmer produce more pounds of protein (meat) from cattle on one acre
            of grazing land or from fish in one acre of pond? Explain.

16. State whether the following statements are TRUE or FALSE, and explain each
         answer.
    A: It is a sign of a healthy environment when a population in that environment has
            reached its biotic potential.
    B: "Ecologically speaking" the death of an individual organism can be a positive
            event for an ecosystem.
    C: In general, an ecosystem is capable of using a variety of energy sources such as
            heat, light, sound, and geothermal to meet its energy needs.
    D: The best way to store all the extra carbon dioxide in the air today is to grow more
            trees.

17. In any community of animals, including humans, disease will claim a certain
        number of the population.
    A: Which individuals in a population are most likely to die from disease?
    B: Generally speaking, will these deaths weaken or strengthen a species? WHY?
    C: Generally speaking, will these deaths aid a species in competing with other
            species in the same community? WHY?
    D: Suggest why some scientists say that modern medicine is reducing man's
            competitiveness in relation to other species?

18. Symbiosis is a form of biotic relationship that often requires millions of years to
        develop and can involve quite complex interactions. The following questions can
        hint at the complexities of symbiotic relationships.
    A: If a tapeworm is a parasite inside a deer, why is it very rare for a tapeworm
            infestation to kill a deer?
    B: Barnacles growing on the skin of a humpback whale is an example of
            commensalisms since the whale neither benefits nor is harmed by the
            barnacles. Why then did the whale allow this relationship to evolve?
    C: E. coli in the human gut is an example of mutualism since we provide it a home
            while it helps us digest our food. But not all cases of mutualism benefit both
            organisms equally. Which organism benefits more from this E. coli - human
            relationship? Explain your answer.