1. In North America, a toxic weed called leafy spurge was accidentally introduced and has grown and spread rapidly, covering millions of acres in north central United States and south central Canada. Leafy spurge is generally avoided by cattle and horses and may be toxic to them. Thus, rangeland where leafy spurge has spread has been damaged by the invasion of this plant.
Plants such as leafy spurge can double their population size every year in part because of their efficient production of large amounts of seeds. Populations that can double every year, such as leafy spurge,
- will do so endlessly, eventually achieving a global distribution.
- are examples of logistic growth.
- probably have more predators than other species.
- exhibit exponential growth as they spread to new regions.
2. Which of the following represents a type of top-down regulation for rattlesnakes living in Arizona?
- the availability of fresh water
- the number of mice in the region
- abundance of rocks under which snakes can hide
- the number of snake-eating hawks in the region
3. Which of the following is analogous to a mutualistic relationship?
- A basketball player is paid by a company to wear its particular brand of shoes.
- A deer hunter stalks and kills a large buck.
- A thief breaks into a store and steals some precious jewels.
- Young lovers leave their initials carved onto a tree, which then gets diseased and dies.
4. Brown-headed Cowbirds lay their eggs in other birds' nests, relying upon another species to raise their chicks. Although many species continue to raise the cowbird chicks, some species reject the eggs and offspring. Further, Brown-headed Cowbirds are rare inside large forests. Which of the following represents an adaptation in response to this cowbird threat?
- breeding birds of other species raising cowbird chicks
- breeding birds of other species nesting in deep forests
- breeding birds of other species attracting cowbird adults to their region
- breeding birds of other species changing to a different type of bird song
5. A large oak tree with its abundant leaves glimmering in the sun on an early fall morning represents
- a heterotrophic producer.
- an autotrophic consumer.
- a heterotrophic consumer.
- an autotrophic producer.
6. If the sun's energy could be measured in units like money, which of the following organisms would be the most expensive to maintain?
- a mushroom
- a fox
- a squirrel
- a sunflower
7. Which biome is characterized by frequent fires and rich soils?
- tropical rainforests
- tundra
- grasslands and prairies
- temperate forests
8. The frequency of crown fires will decrease if
- forests are logged more frequently.
- smaller forest fires are allowed to burn naturally.
- deadwood is allowed to accumulate on the forest floors.
- the environment experiences less precipitation.
9. About 40% of the land's primary production on Earth
- has been appropriated to meet human needs.
- has been destroyed by global climate change.
- uses more oxygen than it produces.
- has been lost just to build enough homes for all of the people on Earth.