Ecology

Ecology

Multiple Select

According to the graph, which of the following is true? (choose 2 answers)

(pH is the measurement of acidity)

• As soil pH increases, the population of marigolds and annual flowers decreases

• As soil pH increases, the population of marigolds and annual flowers increases

• As soil pH increases, the pansies population increases

• As soil pH increases, the pansies population decreases

Multiple Choice

In arid or desert areas where rainfall is slim and places where there are dense forests, soil tends to be more alkaline (basic with a pH higher than 7). For example, marigold flowers, and other annual flowers, have adapted to flourish and thrive in alkaline soil (low pH). However, flowers such as pansies prefer acidic soil (high pH). The graph below shows how the different populations are affected by the pH of soil.

Which of the following answers can be considered correct based off of the graph?

• As the pH increases, the decomposing remains of flowers decrease due to them being covered up.

• As the pH increases, the soil becomes very acidic which kills all flowers that might grow in the area. 

• As the pH decreases, the roots that anchor the flowers become less stable due to the dryness of the desert-like area.

• As the pH increases, the flowers that thrives in acidic (high pH) conditions begins to increase.

Multiple Choice

Pyroclastic rocks are the product of explosive volcanism. When primary succession occurs on pyroclastic rocks, which life-forms will help create the soil by breaking down bare rock?

• Annual flowers

• Grass

• Worms

• Lichen

The pyroclastic rocks are the result of a volcanic eruption.

​Volcanic activity does not involve human influence; therefore, primary succession will begin.

Primary succession does not begin with soil, instead, it starts with "lichen" to break down the rocks into soil.

Explanation

Multiple Choice

Which of the following is true regarding the biodiversity/species diversity between primary and secondary succession?

• Biodiversity/species diversity is greater in primary succession due to the process taking longer.

• There is no difference between the successions in regard to biodiversity/species diversity.

• Biodiversity/species diversity is greater in primary succession due to the fact that the pioneer species ability to become specialized.

• Biodiversity/species diversity is greater in secondary succession due to the fact that the soil already contains traces of decomposed organisms and various seeds.

Explanation

Biodiversity increases as the number of species increases in variety.

Multiple Choice

A new island is formed after a volcano erupts.

What is the order that things would grow?

• Tree, grass, moss

• Lichen, Grass, Shrub, Tree

• Lichen, Shrub, Moss, Tree

• Shrub, grass, moss, tree

​Explanation

Volcanic activity is followed by primary succession.

The order in which primary succession takes place is: lichens, grass, shrubs, trees.

Multiple Choice

Protected ecosystems maintain their ecosystems by not permitting a variety of species populations to be introduced which increases the ecosystem's biodiversity.

Humans can prevent invasive species from entering a certain ecosystem by announcing that ecosystem as a protected ecosystem.

• True

• False

The question is asking whether or not humans can prevent the onset of an invasive species by declaring an ecosystem as a protected ecosystem.

The question...

What is meant by a protected ecosystem is described as an ecosystem which does not allow for a multitude of organisms to enter; thus, increasing its biodiversity.

Before the question...

Explanation

Multiple Choice

What is the main difference between primary and secondary ecological succession?

• Primary builds plant community; secondary builds animal community

• Primary is the first state and secondary is the second stage

• Primary begins WITHOUT soil; Secondary begins WITH soil

• Primary begins WITH soil; Secondary begins WITHOUT soil

• ​Does not begin with soil

• Takes longer

• Requires lichen to break down rocks into soil

• No human influence

Primary succession

Secondary succession

• ​Begins with soil

• Takes less time

• Does not require lichen to break down rocks into soil

• Has human influence

Multiple Choice

What is the term that describes a steady and stable community?

• Peak community

• Climax community

• Primary community

• Disturbed community

​A climax community is the end result of ecological succession.

​

Remember

Multiple Choice

Cattle egrets forage (feed) in fields among cattle. The egret gets easy access to flying insects stirred up by the cattle, and the cattle don't care if they are there or not.

• Mutualism

• Commensalism

• Competition

• Parasitism

The egret benefit by eating the insects near the cattle.

Meanwhile, the cattle do not benefit from the egret presence and neither are they harmed. (Commensalism)

​

Explanation

Multiple Choice

Nitrogen fixing bacteria converts nitrogen gas into a usable form for plants. The bacteria multiply and thrive at the roots of the plants, and the plants are able to form proteins from the nitrogen provided by the bacteria.

What type of symbiotic relationship exists in the example above?

• mutualism

• parasitism

• commensalism

• competition

The nitrogen-fixing bacteria benefit from the plant roots as a place to "live." The plant benefits from the bacteria since it converts nitrogen from the air into a "useable" form to make nutrients.

(Mutualism)

​

Explanation

Multiple Choice

A giraffe has a long neck.

Why would the giraffe need this adaptation?

• to have room to eat more

• to catch birds

• to reach food high above the ground

• to keep warm

Multiple Choice

As time passes, and the trees become taller as the ecosystem attains the status of a climax community, what are the tree competing for at this stage?

• soil

• water

• CO2 (carbon dioxide)

• sunlight

Multiple Choice

Which best describes how a porcupine defends itself from predators?

• it changes color

• it moves rapidly

• it makes a loud sound

• it has sharp quills (spikes)

Multiple Choice

A leech on a mammal would be an example of which symbiotic relationship?

• mutualism

• commensalism

• predation

• parasitism

​The leech benefits from the mammal's blood, meanwhile, the mammal is harmed.

(Parasitism)

​

Explanation

Multiple Choice

Two organisms, A and B, live within the same ecosystem. However, organism B is found in greater amounts than A.

Which of the following could be true?

• Both organisms eat the same food

• Organism A is immune to pathogens (harmful microorganisms)

• There are predators that eat both organisms at an equal rate

• Organism B does not have any predators

Multiple Choice

The wrasse, a small marine fish, periodically cleans harmful parasites from the mouth and body of the moray eel. The moray, in turn, protects the wrasse from larger predators and provides it with a constant supply of food.

This is an example of the type of relationship known as

• commensalism

• mutualism

• competition

• parasitism

Multiple Select

What concepts did this test cover? (choose 3)

• symbiotic relationships

• invasive species

• ecological succession

• evolution