APES 3.5 Quiz and Flashcards for Mastery

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Questions and Answers

What is an example of a density-independent factor that influences population growth?

Disease outbreaks

Competition for resources

Food availability

Natural disasters (correct)

How does increasing food supply affect a population's carrying capacity?

It has no effect on carrying capacity.

It causes a sudden population decline.

It increases the carrying capacity proportionally. (correct)

It decreases the carrying capacity.

What does population size calculation involve?

Only immigration and emigration

A linear addition of birth rates alone

The sum of immigration, births, and the difference of emigration and deaths (correct)

Only births and deaths

Which of the following factors does NOT typically depend on population size?

Natural disasters Signup and view all the answers

Which statement is true regarding a population's carrying capacity?

It is denoted as K. Signup and view all the answers

The intrinsic growth of a population primarily occurs under which conditions?

Under ideal conditions with unlimited resources Signup and view all the answers

Which of these factors restricts population growth based on density?

Water availability Signup and view all the answers

What does a population distribution that is often clumped indicate?

Predation pressures and resource availability Signup and view all the answers

What does carrying capacity (k) refer to?

The maximum number of individuals an ecosystem can support based on limiting resources. Signup and view all the answers

What event marks the beginning of a die-off in a population?

When the population experiences exponential growth beyond carrying capacity. Signup and view all the answers

How does a high population density affect a species?

It increases the likelihood of disease outbreaks. Signup and view all the answers

What is one factor that does NOT influence population distribution?

Birth rates. Signup and view all the answers

What is implied by a population's age structure?

The number of individuals in specific age categories. Signup and view all the answers

In predator-prey dynamics, what follows an increase in hare population?

An increase in lynx population due to more food availability. Signup and view all the answers

What does population sex ratio indicate?

The proportion of males to females in a population. Signup and view all the answers

What typically occurs when a population overshoots its carrying capacity?

A sharp decline in population due to resource depletion. Signup and view all the answers

What type of population distribution is characterized by individuals being spaced out evenly across an area?

Uniform distribution Signup and view all the answers

What defines a metapopulation?

Populations connected by occasional movements of individuals Signup and view all the answers

How does logistic growth differ from exponential growth?

Logistic growth stops increasing once carrying capacity is reached. Signup and view all the answers

What can lead to a skewed sex ratio in a population?

Die-off or bottleneck effects Signup and view all the answers

What describes the 'J-shaped curve' in population models?

It depicts exponential growth over time. Signup and view all the answers

What can cause a population to experience a die-off?

Scarcity of food leading to overshoot of carrying capacity Signup and view all the answers

What is the intrinsic growth rate of a population?

The maximum potential growth rate under ideal conditions Signup and view all the answers

Which of the following best describes density-independent factors?

They have the same impact regardless of population size. Signup and view all the answers

Study Notes

Carrying Capacity

Carrying Capacity (k): the maximum number of individuals in a population that an ecosystem can support based on limiting resources
Fig. 1 (theoretical) shows a steady population that reaches its carrying capacity and stabilises there
Fig. 2 (realistic) shows a population that overshoots its carrying capacity, resulting in a die-off
The Reindeer of St. Paul Island example illustrates how a population can overshoot its carrying capacity and crash due to resource depletion (lichen in this case)
Predator-Prey populations fluctuate, with the predator population increasing when the prey population is high, and vice versa
Real populations do not always fluctuate around carrying capacity; if resource depletion is severe enough, a complete population crash can occur

Population Growth & Resource Availability

Population size, density, distribution, sex ratio, age structure, and abundance are all factors that affect population growth
Population size (N) refers to the total number of individuals in a given area at a given time
Population density refers to the number of individuals per unit area at a given time
Population distribution is a spatial pattern that describes how individuals in a population are spaced out
- Individuals can be distributed randomly, uniformly, or clumped
Metapopulations are groups of spatially separate populations that are connected by occasional movements of individuals between them
Exponential Growth Model
- Intrinsic growth rate is the potential for growth under ideal conditions with unlimited resources, as represented by a J-shaped curve on a graph
- The exponential growth model is defined by the rate at which offspring are produced minus the deaths of individuals or offspring during the same period
Logistic Growth Model
- Logistic growth is a more realistic model of population growth, where population growth is initially exponential but slows down as the population approaches carrying capacity
- The logistic growth model is represented by an “S” shaped curve on a graph
- If food becomes scarce, the population can experience an overshoot where the population becomes larger than the carrying capacity, leading to a population crash
Biotic Potential: the maximum potential growth rate in the absence of limiting resources
Logistic Growth: initial rapid growth as described by biotic potential followed by a leveling off as limiting factors restrict population growth to its carrying capacity
Factors affecting Population Growth
- Density-Independent Factors: These factors affect population growth regardless of population size and include natural disasters like floods, hurricanes, tornados, and fires
- Density-Dependent Factors: These factors affect population growth based on the size of the population and include food, competition for habitat, water, light, and even disease
Specific Examples
- Food is a density-dependent factor, impacting carrying capacity
- Sex ratio is a density-dependent factor, impacting natural breeding rates and recovery from die-off events
Calculating Population Change
- Population size is calculated using the formula: (Immigrations + births) - (immigrations + deaths)

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Description

This quiz focuses on the concepts of carrying capacity and population growth within ecosystems. It explores factors affecting population dynamics, including resource availability and predator-prey interactions. Understand how populations can stabilize or crash based on environmental constraints and resource depletion.