Question

QUESTION 20

You want to determine if an herbivore affects the density of a particular plant in a meadow. You locate three meadows, divide each one in half and build a fence around each half. In one half of each meadow, you exclude herbivores, and in the other half you allow them to stay. What results would you expect to observe if the herbivore had a significant effect upon the plant?

		There would be no difference in plant biomass in each half of each meadow.
		More plant biomass was present when herbivores were present.
		More plant biomass was present when herbivores were absent.

1 points   

QUESTION 21

The tundra is typically found at higher latitudes than the northern coniferous forest. Although average temperatures in the tundra are colder, the most extreme temperatures have been recorded in the northern coniferous forest. What is the reason for this effect?

		A greater rate of heat transfer between water and air results in more moderate temperatures near the coast in the tundra.
		Greater rainfall in the summer warms the northern coniferous forest, and the lack of rainfall in the winter cools it.
		The trees in the northern coniferous forest repel heat in the winter and attract it in the summer.
		The changes in day length in summer and winter are more extreme at intermediate latitudes.

1 points   

QUESTION 22

The relationship between nitrogen fixing bacteria and plants is best described as ________________.

		commensalism
		competition
		parasitism
		mutualism

1 points   

QUESTION 23

Why are average temperatures greater at the equator than at the poles?

		Warm air at the equator rises and cools as it falls near the poles.
		The poles are farther from the sun.
		Winds consistently increase in intensity towards the poles and remove solar radiation from the atmosphere.
		The sun’s rays are more direct at the equator.

1 points   

QUESTION 24

You sample plants in a forest and count five individuals each of 100 species. The species richness of this forest is ___________.

		5
		100
		500
		Species richness cannot be determined from the given information.

1 points   

QUESTION 25

You travel to another forest and also identify 100 plant species. However this time you find 10 individuals each of the five most common species and only one or two individuals each of the remaining 95 species. Which forest has the higher diversity? This one or the one in the previous question?

		this forest
		the forest in the previous question
		The diversity of the two forests is equal.
		A comparison cannot be made using the information given.

Answer 1

QUESTION 20 -

More plant biomass was present when herbivores were absent because herbivores are the animals that eat leaves, shoots, and twigs that affects the plant biomass. Very large animals like elephants, rhinos, and moose are grazers and browsers and they have a significant effect upon the plant.

QUESTION 21 - Greater rainfall in the summer warms the northern coniferous forest, and the lack of rainfall in the winter cools it.

QUESTION 22 - mutualism

A symbiotic relationship in which both organisms benefit. Nitrogen-fixing bacteria live on the roots of legumes in swellings called nodules. The bacteria turn nitrogen compounds into usable forms by plants. The plants provide moisture and nutrients for the bacteria.

QUESTION 23 - The sun’s rays are more direct at the equator because the equator is closer to the sun and the sun's rays hit the earth's surface at a higher angle at the equator and the sun is always directly overhead at the equator.

Questions are many so i have explained the first four.