3.4 Carrying Capacity

3.4 Carrying Capacity

​Objective

​- Enduring Understanding: Populations change over time as a reaction to a variety of factors.

​- Science Practice: Explain what the data implies or illustrates about environmental issues.

​​- Learning Objective: Describe carrying capacity and its impact on ecosystems.

​- Essential Knowledge: When a population exceeds its carrying capacity it can result in resource depletion.

​Lack of resources can lead to famine, disease, or conflict, which results in population dieback.

​Carry Capacity (K)

​X-axis - Time

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​Y-axis - Population Size

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​Get ready to make an assumption about this graph.

Open Ended

What can you assume about this graph?

Take what you know you are measuring and make an assumption.

​Carry Capacity (K)

​Limitations of Growth

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​A rapid population growth typically means that the biotic and abiotic conditions are ideal.

​Carrying Capacity (K)

​A monarch butterfly can lay up to 500 eggs each reproductive cycle.

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It can mate up to 7 times

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Its life span is 2-6 weeks.

Open Ended

Why can't Monarch Butterflies endlessly reproduce?

​Carry Capacity (K)

​Limitations to Growth

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​Eventually a population will reach its Carrying Capacity.

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Even our Renewable resources have an immediate finite supply (they need to recharge)

Exceeding Carry Capacity (K)

​​A population can temporarily 'overshoot' its environments carry capacity,

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​A negative feedback loop (dieback) is initiated to reduce the population size to increase stability.

​ex: disease, famine, competition

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​Dieback can bring the population back to below K.

Open Ended

How does 'overshoot' initiate a postive feedback loop?

​Reindeer of St. Matthew Island

​In 1944, 29 reindeer were introduced onto the land.

​The population quickly explored to over 6,000 by mid-1960's.

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​Why did the population experience a catastrophic dieback?

Open Ended

Why did the reindeer population experience a catastrophic dieback?

​Poor Poor Reindeer

​As the species was introduced to the island, they were likely an invasive species.

​Invasive species typically have a competitive advantage against native species allowing them to outcompete for resources.

​Plentiful resources gave them a reproductive advantage.

​The population was likely increasing before the biotic resources could be renewed.

​Possibly negative feedback initiation was not able to prevent a rapid dieback that the species was not able to recover from.

Multiple Select

What type of species would grow at a rapid rate, create an overshoot and experience a dieback?

• K-selected

• r-selected

• Generalist

• Specialist

Multiple Select

Which species would maintain a population at or just below carrying capacity?

• K-selected

• r-selected

• Generalist

• Specialist

Multiple Select

Which species can better regulate its reproduction?

• K-selected

• r-selected

• Generalist

• Specialist

Open Ended

Estimate the Carrying Capacity of this population.

Open Ended

Speculate a potential cause for the fluctuation in the population over and below carrying capacity.

​Today's Take-away

​Carrying Capacity is not constant.

​Abundant Resources - increases carrying capacity

​​Limited Resources - decreases carrying capacity.

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​More Resource = Large Population

​Limited Resource = Smaller Population

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​Exceeding carrying capacity results in resource depletion

ex: grazing animals can overgraze

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​Lack of resources can lead to famine, disease, or conflict, which results in population dieback.

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​Overshoot can occur due to a lag time; reproduction rates remain high while disease and competition increase death rates.

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​Factors determining carrying capacity are complex and interconnected. Entire ecosystems can be impacted.

​Absent Assignment

​AP Classroom Carrying Capacity Quiz - due Friday 11:45 PM