Ecology Formative Assessment

Scientists are investigating the cause of the large increase in atmospheric carbon dioxide concentration since about 1800. Which of the following provides the best explanation for the increase?

• eruption of large volcanoes

• natural fluctuations of climate

• use of fossil fuels by humans

• photosynthesis by pytoplankton

Leaves fall from deciduous trees in autumn. The carbon in these leaves is returned to the atmosphere through which of the following processes?

• condensation

• photosynthesis

• decomposition

• transpriration

If many trees are removed from a forest by logging, what is the most immediate effect on the carbon cycle in that forest?

• increase in the rate of decomposition

• decreased combustion of fossil fuels

• increased amounts of carbon in the atmosphere

• increased production of organic compounds

When fertilizers run off farmland into streams and ponds, the nitrogen content of the water increases. This can lead to rapid growth of algae in a process called eutrophication. How can this process affect other organisms in the water?

• oxygen is used up as algae is decomposed reducing the amount available to other organisms

• The water becomes better at supporting aerobic organisms

• The algae provide food for the fish and other organisms leading to a decreased algae population

• The extra nitrogen provides additional food for the other organisms, increasing their population

New fuels are being produced by converting corn and grasses into compounds containing alcohols that can be broken down for energy in various engines. The purpose of this research is to

• reduce the use of non-renewable resources

• increase the rate of air pollution

• reduce the rate of homeostasis in organisms

• cause the loss of biodiversity in the rain forests

A builder is proposing a new housing development in an area of western Massachusetts. Construction of the housing development will destroy the wetland habitat in the area. Which of the following would be the most likely consequence of the wetland’s destruction?

• The wetland plants species would disperse tp adjacent meadow habitats

• The population of wetland animals would be unable to survive in that area.

• The wetland animal species would survive by interbreeding with non-wetland species.

• The population of wetland plants would evolve to disperse seeds by wind rather than by water.

Some people see the benefit of wind energy as a clean alternative to fossil fuels for energy production. Others believe it is dangerous for migratory birds. These opinions best illustrate that decisions about alternate energy sources:

• usually will favor older method of energy production over newer methods

• must be made by weighing the risks and costs against the benefits

• must be made by taking into account the present needs of the citizens without looking towards the future

• should be the responsibility of each individual

After the Aswan High Dam was built on the Nile River, the rate of parasitic blood-fluke infection doubled in the human population near the dam. As a result of building the dam, the flow of the Nile changed. This changed the habitat, which resulted in an increase in its population of a certain aquatic snail. The snails, which were infected, released larvae of the fluke. These larvae then infected humans. This situation best illustrates that:

• the influence of humans on a natural system is always negative in the long term

• the influence of humans on a natural system can have unpredictable negative impacts

• human alteration of an ecosystem does not need to be studied to avoid ecological disaster

• human alteration of an ecosystem will cause pollution and loss of finite resources

An animal population decreases from 800 individuals to 600 individuals. Which of the following could explain this change in population size?

• The population size of the animal’s predator increased

• The emigration rate of the animals from the population decreased.

• The number of breeding pairs in the animal’s population increased.

• The number of species competing with the animal for food decreased.

You have been studying population growth of a species of Paramecium, a single celled organism for 18 days. Your data are shown in the graph below. Food was occasionally added to the test tube in which the paramecia were grown. According to the diagram, what is the carrying capacity of the test-tube environment as long as food is added?

• about 10 paramecia

• about 50 paramecia

• about 65 paramecia

• about 100 paramecia