Exam 3: Ecosystems - What Are They and How Do They Work

Human activities affect the hydrologic cycle by making changes to the land surface that reduce infiltration and increase runoff.

Another word for an autotroph is a(n)____________________.

Life on earth depends on the ____ of ____ energy from the sun.​

The hydrologic cycle collects,purifies,and distributes the earth's fixed supply of water.​

​Molecules of water are attracted to each other by ____.

​The coyotes would be classified as ____.

Omnivores are animals that feed only on the flesh of other animals.

Oxygen accounts for about ____ of the air in the atmosphere.​

The earth's life-support system consists of four main spherical systems-the air,water,living things,and ____.​

Given the nature of the carbon cycle,it is possible that a single atom of carbon that is in your skin could have once been part of your own great grandmother,or even a dinosaur.

Photosynthesis is performed by ____.​

A community of different species interacting with one another and with their nonliving (abiotic)environment of matter and energy is called a(n)____.

Although ____________________ cover only about 2% of the earth's land surface,studies indicate that they contain up to half of the world's known terrestrial plant and animal species.

A(n)____________________ consists of populations of different species living in a particular place and potentially interacting with each other.

A primary consumer can also be described as a(n)____________________,a word that means "plant eater".

____________________ allows the earth to hold onto its atmosphere and helps to enable the movement and cycling of chemicals through air,water,soil,and organisms.

Carbon is cycled through the biosphere through ____.​

In the Sonoran desert of the southwestern United States, scientists observed that population clusters of a small cactus were pronounced around nests of desert woodrats. Given this spatial relationship, they began to think the woodrat was related to the seeding of these cactus plants. After years of counting and observing woodrat nests and nearby cactus plants, scientists collected woodrat droppings for laboratory analysis to determine whether they contained cactus seeds. They also collected the droppings and transported them to other areas to see if this would bring about new population clusters of the cactus. Scientists then programmed the data they had collected into a computer. A computer program enabled them to predict that increases in the woodrat population would result in corresponding increases in the cactus population, and likewise, a decrease in the number of woodrats would signal an impending decrease in cactus. -Which statement best describes the scientists' initial observations?​

The ____________________ consists of the earth's intensely hot core,a thick mantle composed mostly of rock,and a thin outer crust.

Unlike nitrogen or carbon,phosphorus ____.​