Limiting Factors Worksheet.docx - Limiting Factors Worksheet Group ... - Free Printable

Let’s go step by step to solve this worksheet.

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First, look at the “Density-Dependent Limiting Factors” section.

Question 4: How is a parasite similar to a predator?

Think about what both do:
- A predator hunts and kills its prey for food.
- A parasite lives on or in a host and takes nutrients from it — often harming the host but not always killing it right away.

Similarity: Both rely on another organism (the prey or host) to survive. They both reduce the population of their target species over time.

Answer: Both parasites and predators depend on other organisms for survival and can limit the size of those populations.

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Question 5: What are some examples of density-dependent limiting factors?

These are things that get worse as more individuals live close together.

Examples:
- Competition for food, water, space
- Disease spreading easier in crowded places
- Predators finding prey more easily when there are lots of them
- Parasites spreading faster in dense populations

Answer: Competition, disease, predation, parasitism.

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Question 6: What are two density-dependent limiting factors shown in the graph?

Look at the graph titled “Predator and Prey Populations on Isle Royale”.

It shows moose (prey) and wolves (predator). When moose numbers go up, wolf numbers later go up too — because they have more food. Then when wolves eat many moose, moose numbers drop — which causes wolf numbers to drop later.

So the two density-dependent factors here are:
1. Predation (wolves eating moose)
2. Food availability (moose running out of plants if too many)

But since the graph specifically tracks predator-prey, the clearest answer based on the graph is:

Answer: Predation and competition for resources (like food).

Wait — let’s check the graph again. The y-axis left is “Number of Moose”, right is “Number of Wolves”. X-axis is years.

When moose increase → wolves increase → moose decrease → wolves decrease.

This cycle shows predation is a key factor. Also, when moose are too numerous, they may run out of food — so competition among moose for food is also happening.

So yes — predation and competition.

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Now the graph questions:

Question 7: What happened to the number of wolves on Isle Royale between 1975 and 1985?

Look at the line with triangles (that’s wolves, according to legend).

In 1975: Wolf count ≈ 20
In 1985: Wolf count ≈ 15

So it decreased slightly — from around 20 to 15.

But wait — let’s read the graph carefully.

Actually, looking at the wolf line (triangles):

- In 1975: ~20 wolves
- In 1980: ~15 wolves
- In 1985: ~15 wolves (maybe dipped to 10 then back?)

Actually, from 1975 to 1985, the wolf population went down overall — started near 20, ended near 15.

But let’s be precise.

From the graph:

Year 1975: Wolf population = approximately 20
Year 1985: Wolf population = approximately 15

So it decreased by about 5.

Answer: The number of wolves decreased from about 20 to about 15.

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Question 8: What happens to the moose population when the number of wolves decreases?

Look at the moose line (circles).

When wolves go down (say, around 1980), what happens to moose?

Around 1980, wolves drop → moose start rising sharply after that.

Same thing around 1990 — wolves drop → moose rise.

So when wolves decrease, moose population increases — because fewer predators are eating them.

Answer: The moose population increases.

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Now fill in the blanks under “Living Factors”:

The sentence says: “An ecosystem is any area that possesses a true climate adjustment to life, change one living factor and the whole system will be affected.”

Then it lists:

Competition – struggle between organisms for limited supply of resources.

Predation – relationship where one organism kills and eats another.

Parasitism – relationship where one organism benefits while the other is harmed.

Symbiosis – close relationship between two different species.

Mutualism – type of symbiosis where both benefit.

Commensalism – type of symbiosis where one benefits and the other is unaffected.

You need to match the terms to the definitions.

Looking at the lines:

First blank: “struggle between organisms for limited supply of resources.” → That’s Competition

Second blank: “relationship where one organism kills and eats another.” → That’s Predation

Third blank: “relationship where one organism benefits while the other is harmed.” → That’s Parasitism

Fourth blank: “close relationship between two different species.” → That’s Symbiosis

Fifth blank: “type of symbiosis where both benefit.” → That’s Mutualism

Sixth blank: “type of symbiosis where one benefits and the other is unaffected.” → That’s Commensalism

So fill in:

Competition
Predation
Parasitism
Symbiosis
Mutualism
Commensalism

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Final Answers Summary:

For the fill-in-the-blanks under Living Factors:

1. Competition
2. Predation
3. Parasitism
4. Symbiosis
5. Mutualism
6. Commensalism

For Density-Dependent Limiting Factors:

4. Both parasites and predators depend on other organisms for survival and can reduce their populations.
5. Competition, disease, predation, parasitism
6. Predation and competition for resources

Graph Questions:

7. The number of wolves decreased from about 20 to about 15 between 1975 and 1985.
8. When the number of wolves decreases, the moose population increases.

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Final Answer:
Living Factors blanks: Competition, Predation, Parasitism, Symbiosis, Mutualism, Commensalism
Q4: Both rely on other organisms and can reduce their populations.
Q5: Competition, disease, predation, parasitism
Q6: Predation and competition
Q7: Decreased from about 20 to 15
Q8: Moose population increases