Ecology Benchmark Review Packet KEY All Answers are red, bolded, underlined, and this font. V. Either/Or Study Questions *key words that give away the answer are red and underlined! Circle the correct word to complete the sentence. 1) All of the living things and abiotic factors in an area are considered a COMMUNITY / ECOSYSTEM. 2) All nutrients in the biosphere move through FOOD WEBS / BIOGEOCHEMICAL CYCLES. 3) The process in which water vapor turns into clouds is known as CONDENSATION / PRECIPITATION. 4) Plants use atmospheric carbon to make sugars in the process of PHOTOSYNTHESIS / RESPIRATION. 5) DECOMPOSERS/ PRODUCERS are important because they recycle nutrients back into the soil or water. 6) OMNIVORES / HERBIVORES are consumers that only eat plants and other producers. 7) The arrows in a food web show the direction that MATTER / ENERGY is flowing. 8) In an energy pyramid, the PRODUCERS / TERTIARY CONSUMERS have the most energy available to them. 9) During Nitrogen Fixation, certain PLANTS / BACTERIA convert Nitrogen gas in the air into a usable form in the soil or water. 10) In the past 100 years, the increased burning of fossil fuels and deforestation by people has caused a(n) DECREASE / INCREASE of Carbon in our atmosphere. 11) If the birth rate is HIGHER THAN/ EQUAL TO / LOWER THAN the death rate, a population will increase. 12) Ecosystems with many different types of organisms have HIGH/ LOW biodiversity. 13) Most living organisms in their natural surroundings reproduce LOGISTICALLY/ EXPONENTIALLY. 14) Competition for food and shelter amongst two troops of monkeys is an example of a DENSITY-­‐
INDEPENDENT or DENSITY-DEPENDENT limiting factor. 15) The graph at right shows a EXPONENTIAL/ LOGISTIC growth curve. 16) Organisms in each trophic level pass on MORE/ LESS
energy than they received. VI. Practice CST Questions 1. After a volcanic eruption has covered an area with lava, which of the following is the most likely order of succession in the repopulation of the area? A lichens →grasses →shrubs →trees
Note: a lichen is a combination of a
B mosses →grasses →lichens →trees fungus and algae that breaks down
C grasses →trees →mosses →lichens rocks to create soil
D shrubs →grasses →trees →lichens 2. For the food chain shown below, which of the following changes would have the most severe consequences? Grass à Crickets à Field Mice à Hawks Note: no water means no producers,
A a drastic decrease in rainfall, causing drought
which means no energy for
B the poaching of predatory hawks by game hunters C the introduction of a second predator that eats field mice everyone else!
D a parasitic infestation that reduces the cricket population 3. Which of these organisms are most helpful in preventing Earth from being covered with the bodies of dead organisms? A herbivores C parasites and viruses B producers D fungi and bacteria Note: these are decomposers
4. Which of these organisms would most likely be found at the top of an energy pyramid? A clams C sharks Note: consumers that eat
B sardines D kelp everything else will be at top
5. A cancer research team has recently discovered a compound found in a certain type of algae that may prevent the growth of tumor cells in human beings. After a few rounds of testing the compound’s effect on human cell growth media in the lab, they observe that the cancer cells do not die completely, but stop dividing. Based on these observations, a researcher suggests that this compound has some effect on mitosis in human cells. This is an example of a: A theory C procedure Note: the words in red imply that
these findings are NOT yet proven,
B hypothesis Note: hypothesis = possible D result
meaning it is a hypothesis
explanation! (not proven yet)
6. A student wants to know if different types of music allow a plant to grow more quickly. She set up an experiment where 3 plants listen to rock music for 2 hours a day, and another three plants listen to rap music for 2 hours a day. At the end she measured the plant height and weight. What is missing in this experimental design? C a procedure A a control Note: need one group with NO D a conclusion B a variable music to compare to!
7. A zookeeper is concerned about the population of tropical birds in the aviary of his zoo. He decides to move the birds from a 20 square foot space to a 60 square foot space. After 6 months, many of the birds seemed healthier and the population increased. Which of the following statements is supported by this data? A food was a limiting factor B as long as the zookeeper keeps giving the birds more space, the bird population will continue to grow Note: “B” is wrong because there is no
C birds reproduce rapidly evidence/not proven the birds will continue to
D the size of the aviary was a limiting factor
grow. (it is a hypothesis). D is correct
because it explains exactly what happened:
the size had prevented the pop from growing.
VII. Open-­‐Ended Study Questions: 1) After a fire destroys a forest, what is the typical order of the secondary succession that takes place? Pioneer species- small plants like grass comes in first. Then shrubs and bushes, smaller young
trees, then bigger, older trees.
2) The following shows a table of the temperature of a green house and the number of tomatoes grown. What conclusion can you draw from this data? Temperature (°C) 8 12 16 18 24 22
# of Tomatoes 4 10 14 18 16 24
The best temperature to grow tomatoes is 22 degrees C. Any warmer or colder you will get
fewer tomatoes.
3) For a food supply, what organism do all others depend on? Producers! (they capture energy from the sun and convert it into sugar)
4) Explain why ecosystems with a higher biodiversity can remain unchanged for hundreds of years: With so many species, some are likely to survive in the event of natural disasters or slow
geological change. This makes them more stable.
5) Explain the difference between an abiotic and biotic factor, and provide three examples of each: Abiotic = non-living. (ex: sun, temperature, rocks, metals, water, soil )
Biotic = living (ex: plants, animals, bacteria, fungi)
6) When rabbits were introduced to Australia over 100 years ago, they began to multiply rapidly and have now become a pest to farmers and have made many of the native plants go extinct. a) Do these rabbits show an exponential or logistic growth pattern? Exponential (keeps growing)
b) Why do they keep multiplying? Since they are not native, there are no natural predators that eat them. And with so
much farming, there is unlimited food. Therefore, there are NO limited factors, so
MORE bunnies.
7) Explain how plants and animals get nitrogen: Bacteria must FIX it for them in the process of Nitrogen Fixation. Plants take this “fixed”
nitrogen from the soil and use it, then animals eat plants.
8) How do humans affect the water cycle by covering the ground with pavement and cement? Preventing PERCOLATION- which is H2O soaking into the ground. (important for producers)
9) In a food chain, the primary producer is the grass, the primary consumer is the mouse, the secondary consumer is the snake, and the tertiary consumer is the owl. a) Write out/draw this food chain here: Grass à mouse à snake à owl
b) What changes can be expected in this food chain if people kill off all of the mice? Snakes will die or have to move because they have no food. Owl will eventually die or
move too, once all of the snakes are gone. Grass would increase.
10) A fungicide is a chemical that kills fungi. Farmers decide to use fungicide on their crops to keep them from molding, but this fungicide gets into the soil of a nearby forest and kills the bacteria and fungus there too. How are biogeochemical cycles affected when decomposers like these are killed? The nutrients (matter) left in dead organisms are not recycled back into the soil, and
producers do not get enough nutrients to be healthy, causing the whole food chain to be
affected!
11) A population’s birth rate and death rate is monitored from 1900-­‐2000. The birth rate fluctuates, with anywhere from 25,000 to 40,000 births each year during that span of 100 years. During that same century, the death rate steadily decreases, with 20,000 deaths at the beginning of the century, and only 8,000 deaths at the end of the century. Combining this information about the birth rate and death rate, what can you conclude about this population from 1900-­‐2000? If the birth rate is 25,000 to 40,000 per year, and the death rate is only 20,000 to 8,000
deaths per year, then for the entire century there were more births per deaths every single
year. When there are more births than deaths, a population increases. Therefore, we can
conclude that during 1900-2000, the population experienced an overall increase.
11) Draw a little picture of what logistic growth looks like: it looks like an “S” because the population
reaches its carrying capacity. (the max number of organisms an ecosystem can hold because of
food, shelter, and other limiting factors)