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

A grassy meadow high in the Sierra Nevada Mountains of eastern California is known to support a variety of organisms. During the summers when grass is thick and lush, and wildflowers abound, butterflies take advantage of this abundant nectar source.  Bears graze on the berries in shrubs at the edge of the meadow. Deer also forage at the edge of the meadow.  In the early mornings, coyotes are known to prey on the squirrel and mouse populations that burrow into the meadow soil.  A variety of birds prey on the butterflies and other flying insects, such as bees and wasps. The coyotes would be classified as ____.

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

If an ecologist spent a summer recording the behavior of grasshoppers in a meadow, the work would be considered laboratory research.

Only about 0.024% of the earth's vast water supply is available to humans and other species as liquid freshwater.

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 connected 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 excluded woodrats from several other areas without cactus plants, then collected woodrat droppings and added those to half of these areas to examine whether the droppings were associated with the growth of 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. - What finding would suggest that the woodrats were spreading cactus seeds?

An example of a producer is ____.

Figure 3.6 What are all of the components that can be categorized as abiotic in the accompanying figure of an ecosystem?

Complex networks of interconnected food chains in ecosystems are best described as ____.

Sometimes ecologists carry out controlled experiments by isolating and changing a variable in part of an area and comparing the results with nearby unchanged areas.

A group of individuals of the same species living in a particular place is a(n) ____.

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 connected 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 excluded woodrats from several other areas without cactus plants, then collected woodrat droppings and added those to half of these areas to examine whether the droppings were associated with the growth of 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 phase of the study could be described as modeling?

Which of the following best represents the process of aerobic respiration?

A large portion of the planet's nitrogen can be found in the ____________________, which is not the case for phosphorus in the phosphorus cycle.

An organism can be described as a tertiary consumer if it eats ____.

Figure 3.12 What trophic level is occupied by the emperor penguin in the above food web? Briefly state the reason for your choice.

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

Bacteria in soil convert ammonia and ammonium ions to ___________________.

Why is a vegetarian diet more efficient than a meat-based diet?

Despite its low net primary productivity (NPP), the open ocean produces more of the earth's biomass per year than any other ecosystem or life zone because ____.

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