Population and the Environment

Which best describes how an organism’s niche is determined?

• An organism's habitat and inherited traits determine its niche.

• An organism’s habitat and ability to reproduce determine its niche.

• An organism's size and ability to fight determine its niche.

• An organism's population and prey determine its niche.

The burrowing owl is found in dry, open areas such as grasslands, prairies, savannas, deserts, farmlands, golf courses, and urban areas throughout most of western United States and Florida, Central America, and most of South America. It makes its home in burrows of other animals and primarily eats insects and small rodents. As humans build more cities, nearby burrowing owl habitats change due to destruction of burrows and loss of prey. Which is the least likely outcome of the habitat changes that are described?

• The niche of the burrowing owl may change as it adapts to the changes.

• The niche of the burrowing owl may change as it moves to a new habitat.

• The population of the burrowing owl may be reduced or even become extinct.

• The population of the burrowing owl may increase in its new surroundings.

Interactions between organisms and their environment impact the organism’s overall population. The jaguar Panthera onca is the largest cat in North America. It is found in areas across the Southwest, including Arizona, New Mexico, and Texas. It is a carnivore that has powerful jaws and sharp teeth and preys on fish, turtles, and many smaller mammals. Which shows the relationship between the jaguar and turtles?

• adaptation principle

• competitive exclusion principle

• niche principle

• predator-prey relationship

How would an increase in nest sites affect a population of pigeons?

• The population would decrease.

• The population would increase.

• The population would remain almost the same.

• The population would be reduced the next year.