1.10 Niches and Symbiotic Relationships

1.10 Niches and Symbiotic Relationships

SWBAT describe the significance of competition in determining realized niches and explain how symbiotic relationships provide advantages for organisms in certain niches.

Multiple Choice

Which of the following is an example of an organism interacting with an abiotic factor?

• Cows eating grass

• Rocks adding nutrients to the soil

• Sun warming and melting ice into liquid water

• Plants absorbing water through their roots

Multiple Choice

In the food web, the SHREW is a _____________ and if removed will cause_________.

• Secondary consumer; the snake population to decline due to lack of food

• Secondary consumer; the rabbit population will increase because there will be more food available

• Primary consumer; the mouse population to go up because there will be less competition

• Primary producer; the insect population to increase because it has less predators.

Multiple Choice

The estimated carrying capacity of deer in Upper Dublin Township is 50.  If the population reaches 150, what is the LEAST likely thing to happen?

• Some township residents will begin to feed the deer to prevent starvation.

• The population will decrease due to increased car accidents.

• The population will continue to increase in size.

• The deer will leave Upper Dublin and emigrate to Abington looking for food.

Open Ended

The number of hunting permits has been doubled in a certain township in an effort to maintain the population of deer at its carrying capacity.  EXPLAIN how this would benefit the ecosystem. 

Draw

Sketch the population growth curve to show what the population of deer must look like.

​Logistical

​Exponential

Types of Population Growth

Multiple Choice

What type of growth occurs when there are few limiting factors?

• Exponential growth
• Cyclical growth
• Logistic growth
• Linear growth

Open Ended

Why might a population reach its carrying capacity?

Multiple Choice

What type of growth occurs when a population reaches its carrying capacity?

• Logistic growth
• Exponential growth
• Linear growth
• Cyclical growth

In order to explain the relationship limiting factors and population size: 

• Identify the type of population growth 

• If exponential: 

  1. Determine lack of limiting factors 

• If logistical: 

  1. Identify components within the ecosystem that slow/level off growth (space, resources, etc.) 

To identify the type of population growth: 

• Visualize the shape of the population curve

• Identify the curve as “J” or “S” shaped

• Connect shape of curve to type of population growth 

  • J Shaped- exponential growth

  • S Shaped – logistical growth 

• If necessary, identify presence/lack of presence of limiting factors .

​THINKING STEPS:

ACTIVITY 1

1. ​Describe population densities of the microorganisms for when they are separate and when they are together. 

2. Propose an explanation for the population pattern when the microorganisms live together. 

3. The relationship between Paramecium aurelia and Paramecium caudatum is an example of competitive exclusion. Generate an initial definition for this pro

​What is competitive exclusion? 

Competition reduces the range of resources an individual or a species can exploit. This typically results in competitive exclusion (where one species utilizes resources more efficiently, driving the other species to local extinction).

Partner Practice

According to fossil records and recent published observations, two species of leaf-eating beetles (species A and B) have existed on an isolated island in the Pacific Ocean for over 100,000 years. In 1964 a third species of leaf-eating beetle (species C) was accidentally introduced on the island. The population size of each species has been regularly monitored as shown in the graph above.

1. Identify the type of population growth initially shown by Species C. 

2. Propose an explanation for the pattern of population density observed in Species C. 

3. Describe the effect that the introduction of Species C has had on the population density of Species A. 

4. Explain the observed pattern of population density. Your explanation should reference competitive exclusion.

Multiple Choice

Which of the following is an example of competitive exclusion?

• A parasite living in the intestines of a dog

• A pack of wolves driving another pack of wolves out of the ecosystem

• Two male peacocks competing for the attention of a female

• Two friends working on the same project together

​What is the relationship between competitive exclusion and population density?

When two populations of different organisms are competing for the same resources, one population will be better fit to access the resources. Because resources are limited, the population that can access the resources maintains population density while the population that is less equipped will see a decrease in population density.  

A species’ niche is its ecological role or “way of life,” which is defined by the full set of conditions, resources, and interactions it needs. For example, two fish species’ niches are defined by ranges of salinity (saltiness), pH (acidity), and temperature it can tolerate, as well as the types of food it can eat. The two species share the same fundamental niche, but due to competitive exclusion, cannot survive together. 

Using the diagram below, explain the relationship between fundamental niche and realized niche.  

​

Types of Niche (neesh)

A fundamental niche is the range of environmental conditions that a viable population can occupy and use, without any other limiting factors present that might constrain the population.

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​Fundamental Niche

Open Ended

What is the relationship between a fundamental niche and a realized niche?

​Independent Practice:

Explain how the warblers as competing species are able to exist in the same environment.  Your response should include the following terms: fundamental niche and realized niche, and competitive exclusion.

Labelling

Population A is the original species (red). Population B is introduced (blue). Using the graphs below, identify the relationship between organisms as commensalism, mutualism, or parasitism.

Drag labels to their correct position on the image

parasitism

mutualism

commensalism

In 1890, 60 common starlings native to Europe were released in Central Park in New York City by someone trying to introduce all the birds mentioned in Shakespeare’s plays to the New World. Today, there are millions of starlings in the US. 

1. What type of growth did the starling population likely show between 1890 and 1920?

2. Prior to 1890, the United States was:

A) part of the realized niche of starlings but not their fundamental niche. 

B) part of the fundamental niche of starlings but not their realized niche.

C) part of the fundamental and realized niches of starlings.

D) not part of either the fundamental or realized niche of starlings.

3. Explain your answer to the question above. Use the terms fundamental niche realized niche, and tolerance in your answer.

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​1.11 Exit Ticket: Niche and Symbiotic Relationships