Category 5 Interdependence within Environmental Systems

Parrotfish are herbivores that are found in coral reefs.  To escape predation, a parrotfish will graze with a rabbitfish, which has venomous spines at the end of its pelvic fins.  The rabbitfish does not benefit from this relationship.  Which type of relationship do the parrotfish and the rabbitfish have in the coral-reef environment.

• Commensal
• Mutualistic
• Predator-prey
• Parasitic

As ecosystems move through the stages of succession, the populations of organisms in them change.  Which of the following describes the stage of succession likely to have the most species diversity?

• A newly formed volcanic island
• An agricultural field that has not been plowed for one year
• A temperate forest that has never been cleared by logging
• A field that is regularly mowed

On March 24, 1989, an oil tanker ran aground on Bligh Reef in Prince William Sound, Alaska, and spilled millions of liters of crude oil.  The graph shows pink salmon populations in Prince William Sound from 1970 to 1999.
What do these data suggest about the effect the oil spill had on pink salmon?

• Pink salmon were nearly eliminated after the oil spill.
• Pink salmon populations steadily declined in the 10 years following the spill.
• Pink salmon populations declined and never fully recovered.
  
• Pink salmon populations seemed to be minimally affected.

In recent years humans have interfered with the natural balance within deer populations in various ecosystems.  The interference includes eliminating predators of the deer.  Which of the following statements correctly describes the long-term outcome of this interference?

• The deer that are the fastest and most agile will survive and reproduce.
• The deer population will be too large to be supported by producers.
• Other browsing species will thrive and out compete the deer.
• The producers will evolve into species that are less palatable to the deer.

The mimosa plant displays thigmotropism by collapsing its leaves in response to touch, as shown in the pictures below.  The plant on the left is undisturbed.  The upper stem of the plant on the right has been touched.
What is the most likely benefit of this mechanism for the plant?

• Protection from a loss of minerals to the environment
• Protection from poor light availability
• Protection from herbivores by becoming less attractive
• Protection from overwatering

The food web shows the flow of energy through a sagebrush-steppe ecosystem.
Which of these organisms are in a trophic level that receives a larger percentage of the energy captured by the producers than the percentage received at the bats’ trophic level?

• Mountain Lions
• Snakes
• Hawks
• Ground squirrels

A student is asked to draw a food web in which the same organism is a primary consumer as well as a secondary consumer.  How should the organism be represented in the food web?

• The organism must have an arrow pointing from it to a tertiary consumer and another arrow pointing from it to a decomposer.
• The organism must have an arrow pointing from it to a secondary consumer and another arrow pointing to it from the top predator.
• The organism must have an arrow pointing to it from a producer and another arrow pointing to it from a primary consumer.
• The organism must have an arrow pointing from it to a primary consumer and another arrow pointing away from it to a decomposer.

Bats eat insects that damage crops and mosquitoes that are vectors for disease.  One million bats can eat several tons of insects per night, saving billions of dollars in pesticides yearly. Agricultural and public health scientists are concerned about the spread of white-nose syndrome (WNS).  WNS is a result of a fungus that can infect cave-dwelling bats. While bats hibernate during winter months, the fungus covers the bats’ face and wings.  WNS has a near 100% mortality rate, and 5.7 million bats have died since the discovery of the fungus in 2006. Many scientists are searching for ways to protect these bats. The relationship between this fungus and bats can best be defined as -

• commensal, because the bats provide a surface for the fungus to grow
• parasitic, because the fungus obtains nutrients and shelter from the bats
• competitive, because both organisms use caves as shelter during the winter
• mutualistic, because the relationship involves two distinct species living together

How do an increase in the organic matter in soil and an increase in soil depth affect the population of plants in an area?

• Larger plants become the dominant organisms.
• Mosses replace flowering plants.
• Nitrogen-fixing bacteria kill young trees.
• Grasses become diseased.

In dry desert areas poor drainage can lead to a buildup of salt in water supplies. A student performed an investigation to study the effects of salinity on the germnation rates of seeds.  The student placed seeds in several solutions containing 0% to 3% salt.  The length of the radicle, which is the root of the germinating seed, ranged from 49 mm in the 0% salt solution to 0 mm in the 3% salt solution.  The data from this investigation suggest that increased salinity in more areas may lead to a decrease in which of the following?

• Air pollution
• Food production
• Oceanic evaporation
• Nonrenewable resources