CRM 3.2 - Population Ecology

In an ecosystem where the foxes eat the rabbits, the carrying capacity of both populations has been reached. How does the emigration of rabbits affect the carrying capacity of the fox population?

• The carrying capacity of foxes will increase

• The carrying capacity of foxes will decrease

• Carrying capacity is not affected by emigration

• The carrying capacity of foxes would stay the same

Using the graph above, what could have caused the wolf population to rise after the rabbits reached carrying capacity?

• A new food source was introduced to the environment

• Several wolves emigrated from the environment

• There was a decrease in the rabbit population

• A new rabbit predator was introduced to the environment

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The Florida Panther is a large cat that is native to the southern parts of Florida. Recently, the panther's main food source, rabbits, have been infected with a deadly disease that only affects rabbits. How would this most likely affect the population of panthers in the coming years?

• The panther population will decrease since they won't have access to as much food

• The panther population will not be affected because they will adapt to eating other food

• The panther population will increase because they will produce more offspring to make up the difference

• The panther population will decrease because they will contract the disease.

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Michael feeds his fish two teaspoons of fish food every day. Over a period of 4 months, the average population is 40 fish. She increases the amount of food to 2 teaspoons per day. After another 4 months, the population is now 65 fish. How is this possible?

• Food was the limiting factor

• The size of the tank was the limiting factor

• Fish reproduce faster when they have more food

• As long as Michael keeps giving them more food, the fish population will continue to get bigger

Sea turtles are marine reptiles. They rely on an external heat source, which makes them ectotherms. They are commonly found in waters off the Mid-Atlantic and Northeast United States during the summer and early fall. Typically, they begin to migrate south to warmer water by late October. However, some sea turtles strand along our shores when water temperatures drop rapidly or unexpectedly. This is called “cold stunning.” Cold stunning is similar to hypothermia in humans. Initial symptoms include a decreased heart rate, decreased circulation, and lethargy, followed by shock, pneumonia and possibly death.

Based from this passage, why do sea turtles migrate?

• Sea turtles migrate because their food source is more abundant in the south during the fall.

• Sea turtles migrate because predators become more abundant in the Mid-Atlantic and Northeast of the U.S. during the summer and early fall.

• Sea turtles migrate because humans are fishing more often in the areas where they are commonly found during summer and fall.

• Sea turtles migrate because they depend on external sources of heat to help maintain their body temperature.

In 1910, there were approximately 100,000 cheetahs living in the wild. That number has now dropped to less than 10,000 and has drastically reduced the gene pool. What will be the consequence of this reduction?

• Competition in the population will increase

• Inbreeding will be less frequent among the remaining population

• Cheetahs will be more vulnerable to environmental changes

• The surviving cheetahs will be better able to adapt.

The number of pythons found throughout the Everglades has increased in recent years. These huge snakes are invasive to Florida and are believed to have been released into the wild by pet owners. Wildlife biologists have attempted to capture and remove these pythons. Which statement best explains the biologists' reasons for removing these pythons from the Everglades?

• The pythons could attract other non-native species to the area.

• The pythons could adapt to overcome diseases common to native snakes.

• The pythons could prey on native organisms and cause native populations to decline.

• The pythons could begin to interbreed with native snakes and produce a more successful species.

A student was studying how a change in abiotic factors can influence living organisms. She set up the experiment as follow:

1) Fill two glass fish tanks, labeled Tank A and Tank B, with 5 liters of water each.

2) Add a small fish and several plants to each tank.

3) Seal both tanks so that no air can leave or enter.

4) Place Tank A in a bright room and Tank B in a dark room.

The student noticed after 45 hours, the fish in Tank B died while the fish in Tank A remained healthy. Based on the results of the experiment described above, what is the best explanation for why the fish in Tank A lived and the fish in Tank B died?

• Fish died in Tank B due to a lack of carbon dioxide.

• Fish died in Tank B because the tank was sealed.

• Fish died in Tank B due to lack of oxygen.

• Fish died in Tank B because the temperature was too low.

The lead biologist at a Central Florida wildlife management area has noticed that there had been a significant increase in the population of native bats after a local school had added several bat houses to the management area as part of a community service project. What does this observation most likely indicate about the bat's relationship to the newly installed bat houses?

• Shelter was a limiting factor for the bat population.

• Shelter was a biotic factor needed by the population of bats.

• Shelter will became a surplus resources after several generations.

• Shelter will act as a selective pressure to evolve a new species of bats.

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On remote islands, immigration and emigration usually do not have a large effect on population sizes. A bird population on a remote island remains at a relatively constant size year after year. Which of the following most likely describes the birthrate and the death rate for this population?

• Birth rate and death rate are both zero.

• Birth rate and death rate are close to equal.

• Birth rate is significantly less than death rate.

• Birth rate is significantly greater than death rate.

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