Dynamic Nature of Ecosystems Assessment

The peppered moth (Biston betularia) has two forms, a white-bodied and a dark-bodied form. The table provided shows the percentage of each type in a moth population over several years.

The data provided on the shift in population of the peppered moth could support a claim that this population is responding to a change in the environment. In order for this data to support that claim, what other data would be needed?

• Data showing a steady change in the color of trees in this habitat between 1965 and 1985.

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  Data showing that eventually there were no more dark-bodied moths after 1985.

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  Data showing that in the years after 1985 the trend reversed leading to more dark moths.

• Data showing that, in 1965, the two forms migrated from different habitats

Information on brown tree snakes is provided along with information on the island of Guam. Brown tree snakes were first brought to Guam in 1950.

Which of the following would provide evidence that the change to this environment brought about by the introduction of the brown tree snake has had an effect on the populations of organisms that lived on Guam?

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  Any of the military bases on Guam were closed in the 1980’s.

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  Several other species of snakes were known to live on Guam before 1950.

• The population of lizards on Guam in 1960 was very small.

• The longest brown tree snake ever found on Guam measured three meters in length.

A physical disruption to an ecosystem occurred when a highway was built through a forest. Which of the following would provide evidence that the addition of a highway to this forest affected populations?

• The amount of water runoff from higher elevations increased after the highway was built.

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  The trees that were not cut down during the construction of the highway continued to grow.

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  There were fewer species of nesting birds living in the forest after the highway was built.

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  A greater area of the forest floor was exposed to the sunlight after the highway was built.

Bank swallows are birds that make their nests on the edges of rivers. Bank swallows can’t swim or breathe underwater. They feed on flying insects and, in the spring, lay four or five eggs. Which of the following observations would provide evidence that the population of bank swallows was affected by a change in the environment?

• The largest swallows catch and eat more insects than the smallest ones.

• Swallows that lay four eggs one year may lay five eggs the following year.

• Fewer swallows build nests along the river when the water level rises.

• Swallows share a food source with other animals that also eat insects.

The trout is a fish that lays its eggs in cold fresh water but spends some of its life in the ocean. Trout eat smaller fish. The graph provided shows the population of trout in the state of Wisconsin between the years 1999 and 2014.

The trout is a fish that lays its eggs in cold fresh water but spends some of its life in the ocean. Trout eat smaller fish. The graph provided shows the population of trout in the state of Wisconsin between the years 1999 and 2014.

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  A hard freeze of many of the lakes in Wisconsin in the winter of 2006

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  The slow rise in lake temperatures in Wisconsin between 1999 and 2014

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  The rise in population of smaller fish in Wisconsin lakes between 2010 and 2011

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  A shift in ocean currents that occurred in 2000 and again in 2001

Koalas live almost entirely on leaves from eucalyptus trees, and they are native exclusively to Australia. What will happen if the koalas’ habitat is destroyed?

An illustration of a water lily is provided below. If annual rainfall increased and caused ponds in this ecosystem to become deeper, how might the traits of these water lilies change after many generations?

The resurrection fern (Selaginella lepidophylla) can shrivel up into a ball and remain that way for many years. When moisture is available, the dry leaves absorb the water and unroll. The plant will then turn green and grow. Under which environmental conditions did this ability develop?