BSC 385 Exam 3: Ecology Competition & Predation

Black walnut trees produce a chemical called juglone in many parts of the tree, including the roots. In producing the chemical the tree is able to decrease growth of some plants around the tree. This would be an example of what type of competition?

The mathematical models for predator and prey interactions (like Lotka-Volterra) are fundamentally based on what assumption about the prey population in the absence of predators?

Chameleon color patterns used for concealment are an example of what?

What type of competition is allelopathy?

White-nose syndrome in North American bats is an example of a parasite that was likely transmitted by which mode?

Which of the following is generally NOT considered a resource that organisms compete for?

A gray squirrel consuming acorns in a forest, thereby impacting other species' ability to consume those same acorns, would be an example of what type of competition?

What is considered the primary driving force in the approximately 10-year cycle of lynx and snowshoe hare abundance?

The bacterium that causes chlamydia in humans can be transmitted from mother to fetus by _____ transmission or between any two individuals by _____ transmission.

Vaccinations slow or stop the spread of diseases primarily by what mechanism?

In the logistic model with delayed density dependence, how does an increase in the length of the time delay ($ au$) affect population dynamics?

In the logistic growth model with time delays, what does the product of the intrinsic growth rate and the time delay ($r au$) indicate?

A group of spatially separated subpopulations, connected by occasional dispersal, where each subpopulation has its own population dynamics, is an example of what?

Which statements about population cycles are correct? I. are increases and decreases of population size occurring at regular time intervals II. can be caused by overshooting carrying capacity and subsequent die-offs. III. indicate that a species is about to become extinct

A species of grass is significantly affected by the amount of rainfall in the spring. In years of high rain, the grass population grows much better than in years of low rain. This unpredictable variation in population growth due to weather is an example of what?

When immigrants arrive in a declining subpopulation and prevent that subpopulation from going locally extinct, this phenomenon is known as what?

According to the exponential growth model ($rac{dN}{dt} = rN$), what change would reduce a population's doubling time?

In Carl Huffaker's predator-prey experiments with mites on oranges, which addition to the experimental setup allowed for sustained oscillations in predator and prey populations by increasing habitat complexity?

Given the Lotka-Volterra predator-prey relationships, under what condition related to prey population size ($N$) would the predator population ($P$) be stable ($rac{dP}{dt} = 0$)?

Given the Lotka-Volterra predator-prey relationships, under what condition related to prey population size ($N$) would the predator population ($P$) increase ($rac{dP}{dt} > 0$)?

Which type of predator functional response (Type I, II, or III) includes a phase of accelerating predation rate at low prey densities, often attributed to the predator developing a 'search image' or learning?

Studies involving different species of Calycomyza leaf miners sharing the same host plants and parasitoids suggest what type of competition might be occurring between the leaf miner species?

The Lotka-Volterra competition model predicts that competitive exclusion of one species is the only possible outcome.

Which predator functional response curve(s) (Type I, Type II, Type III) show(s) predator satiation, meaning the predation rate levels off at high prey densities?

What principle states that population growth is dictated not by total resources available, but by the scarcest resource (limiting factor), and what potential complexity does this principle sometimes fail to consider?

When bald eagles compete with each other for fish out of the same lake, what type of competition is occurring?

When any two different species compete for the same limited resource, what type of competition is occurring?

What term describes the highest possible per capita rate of increase ($r$) for a population size under ideal environmental conditions with unlimited resources?

The old saying -- 'Red and yellow, kill a fellow; red and black, okay Jack!' -- distinguishes the venomous coral snake from the non-venomous king snake, which mimics its coloration. The coloration of the harmless king snake is an example of what phenomenon?

A herd of 25 reindeer was introduced to St. Paul Island in 1911. The population grew rapidly and then crashed dramatically. Which statement(s) accurately describe this scenario?

1. The pattern closely fits the logistic model including carrying capacity.
2. The population experienced an overshoot of the carrying capacity.
3. The population experienced a die-off.

Why does the traditional biological species concept (based on reproductive isolation) often not apply well to microbes, and what alternative model focuses on ecological adaptation?

Describe the key ecological factors impacting the spread and prevalence of Lyme disease in the Mid-Atlantic and Northeastern US.

Black walnut trees produce a chemical called juglone in many parts of the tree, including the roots. In producing the chemical the tree is able to decrease growth of some plants around the tree. This would be an example of what type of competition?

The mathematical models for predator and prey interactions, such as the Lotka-Volterra models, are fundamentally based on what assumption about the prey population in the absence of predators?

Chameleon color patterns, used for blending into the environment, are an example of what phenomenon?

What specific type of interference competition is allelopathy?

White-nose syndrome, a fungal disease devastating North American bat populations, is believed to have spread primarily through which mode of transmission?

Resources are generally defined as entities consumed by an organism that increase population growth rates as they become more available. Provide an example of an environmental factor that is typically NOT considered a resource under this definition.

A gray squirrel consuming acorns in a forest, thereby reducing the number of acorns available for other acorn-eating species, exemplifies what type of competition?

What ecological interaction is considered the primary driving force behind the classic 10-year population cycles observed in snowshoe hares and their lynx predators?

The bacterium that causes chlamydia in humans can be transmitted from mother to fetus by _____ transmission or between any two individuals (e.g., through sexual contact) by _____ transmission.

How do vaccination programs primarily work to slow or stop the spread of infectious diseases within a population?

In logistic growth models that incorporate delayed density dependence, what is the general effect of increasing the length of the time delay ($ au$) on population dynamics?

In the logistic growth model with time delays ($rac{dN}{dt} = rN(1 - rac{N_{t- au}}{K})$), what aspect of population dynamics is indicated by the magnitude of the product $r imes au$ (intrinsic growth rate times the time delay)?

What term describes a group of spatially distinct subpopulations that are connected by occasional migration between them?

Which statements accurately describe population cycles? I. They involve increases and decreases of population size occurring at regular time intervals. II. They can be caused by factors like delayed density dependence (overshooting carrying capacity and subsequent die-offs). III. They inherently indicate that a species is nearing extinction.

A species of grass exhibits significant year-to-year variation in survival rates primarily due to unpredictable fluctuations in spring rainfall. This type of variation driven by random environmental factors is known as what?

In metapopulation dynamics, what is the term for the phenomenon where immigration from other subpopulations prevents a declining local subpopulation from going extinct?

According to the exponential growth model ($N_t = N_0 e^{rt}$), what change in the intrinsic growth rate ($r$) would cause a population's doubling time to decrease?

In Carl Huffaker's classic experiments using mites on oranges to study predator-prey dynamics, what modification involving wooden posts and Vaseline barriers, which increased habitat complexity, was crucial for achieving sustained oscillations of both predator and prey populations?

Given the Lotka-Volterra predator-prey model, where the predator population dynamics are described by $dP/dt = acNP - mP$, under what condition related to the prey population size ($N$) will the predator population remain stable (i.e., $dP/dt = 0$)?

Given the Lotka-Volterra predator-prey model ($dP/dt = acNP - mP$), under what condition related to the prey population size ($N$) will the predator population increase (i.e., $dP/dt > 0$)?

Which type of predator functional response (Type I, II, or III) is characterized by a sigmoidal (S-shaped) curve, often reflecting the development of a 'search image' or learning by the predator at low prey densities?

Imagine two herbivorous insect species (e.g., Calycomyza species) that do not directly compete for food plants but share a common parasitoid wasp. If an increase in the population of one herbivore species leads to an increase in the parasitoid population, which then causes a decline in the second herbivore species, what type of indirect interaction is occurring between the two herbivore species?

When plotting population size ($N$) versus time ($t$) for a population undergoing exponential growth ($r > 0$) on standard arithmetic axes, what characteristic shape does the curve exhibit?

In the geometric growth model, $N_{t+1} = \lambda N_t$, what is the trajectory of the population size over time if the finite rate of increase, $\lambda$, is exactly equal to 1?

What shape characterizes the curve of population size versus time under the logistic growth model, and what do the parameters $r$ and $K$ represent?

Consider the standard Lotka-Volterra competition equations: $\frac{dN_1}{dt} = r_1 N_1 (1 - \frac{N_1 + \alpha N_2}{K_1})$ $\frac{dN_2}{dt} = r_2 N_2 (1 - \frac{N_2 + \beta N_1}{K_2})$ Under what specific conditions (values of the competition coefficients $\alpha$ and $\beta$) do these equations simplify to independent logistic growth for each species?

True or False: The Lotka-Volterra competition model predicts that competitive exclusion of one species by another is the only possible long-term outcome.

Analysis of a forest stand's age structure reveals a large number of very old white pine trees but very few seedlings or saplings established since the late 1700s. What might this age structure suggest about white pine recruitment in this stand over the past couple of centuries?

Which types of predator functional response curves (Type I, II, or III) explicitly incorporate the concept that a predator's rate of consumption levels off at high prey densities due to limitations like handling time or satiation?

What is a primary limitation of Liebig's Law of the Minimum when applied to organismal growth and resource requirements?

When two bald eagles fight over a fish they both caught simultaneously from the same lake, what specific type of competition is occurring?

How is interspecific competition defined?

What does the parameter 'r', the intrinsic rate of increase, represent in population growth models?

The common phrase 'Red and yellow, kill a fellow; red and black, okay Jack!' helps distinguish the venomous coral snake from the harmless king snake, which has similar coloration. The king snake's resemblance to the dangerous coral snake is an example of what phenomenon?

A herd of 25 reindeer introduced to St. Paul Island in 1911 exhibited rapid initial growth followed by a dramatic population crash. Which of the following descriptions accurately apply to this famous population trajectory?

1. The entire pattern closely fits a simple exponential growth model.
2. The population grew far beyond the island's carrying capacity, experiencing an overshoot.
3. Following the overshoot, the population experienced a massive die-off.

Why does the traditional biological species concept (based on reproductive isolation) often prove inadequate for classifying microbes? What alternative concept, mentioned in class, provides a more functional approach focusing on ecological niches and adaptation?

Describe several key ecological factors that interact to influence the risk and spread of Lyme disease, particularly in the Mid-Atlantic and Northeastern US.

If a life table shows a total population size of N1 individuals in year 1 and N2 individuals in year 2, how would you calculate the geometric growth rate ($\lambda$) for the population between year 1 and year 2?

Black walnut trees produce a chemical called juglone in many parts of the tree, including the roots. In producing the chemical the tree is able to decrease growth of some plants around the tree. This would be an example of what type of competition?

The mathematical models for predator and prey interactions (like Lotka-Volterra) are fundamentally based on what assumption about the prey population in the absence of predators?

Chameleon color patterns that allow them to blend into their surroundings are an example of what?

What type of competition is allelopathy, where one organism produces biochemicals that influence the growth, survival, or reproduction of other organisms?

White-nose syndrome in North American bats, caused by a fungus that spread rapidly among bat colonies, is an example of a parasite that was likely transmitted primarily by what method?

Which of the following is generally NOT considered a consumable resource for which organisms compete?

A gray squirrel consuming acorns in a forest, thereby reducing the number of acorns available for other species like deer or jays, would be an example of what type of competition?

What is considered the primary driving force behind the famous 10-year population cycles of snowshoe hares and their lynx predators?

The bacterium that causes chlamydia in humans can be transmitted from mother to fetus by _____ transmission or between any two sexually active individuals by _____ transmission.

How do vaccinations primarily slow or stop the spread of infectious diseases within a population?

In the logistic growth model incorporating delayed density dependence, how does increasing the length of the time delay ($τ$) tend to affect population dynamics?

In the logistic growth model with time delays ($dN/dt = rN(1 - N_{t-τ}/K)$), what ecological dynamic does the magnitude of the product $rτ$ (intrinsic growth rate times time delay) indicate?

What term describes a group of spatially distinct subpopulations that are connected by occasional dispersal between them?

Which statements accurately describe population cycles? I. They are regular increases and decreases in population size over time. II. They can be caused by factors like delayed density dependence leading to overshoot and die-off. III. Their presence always indicates that a species is critically endangered and about to go extinct.

A species of grass shows significant year-to-year variation in survival rate depending on unpredictable rainfall patterns (high survival in wet years, low survival in dry years). This type of fluctuation driven by unpredictable environmental changes is an example of what?

In metapopulation theory, what is the term for the phenomenon where immigration from other subpopulations prevents a small or declining subpopulation from going extinct?

According to the exponential growth model ($dN/dt = rN$), what change would cause a population's doubling time to decrease?

In Huffaker's classic laboratory experiments demonstrating predator-prey cycles using mites on oranges, what key modification to the experimental setup allowed the prey and predator populations to persist and oscillate instead of quickly going extinct?

Given the Lotka-Volterra predator-prey equations ($dP/dt = acNP - mP$), where P=predator pop., N=prey pop., m=predator mortality, a=capture efficiency, c=conversion efficiency, under what condition related to prey density would the predator population growth rate be zero ($dP/dt = 0$)?

Given the Lotka-Volterra predator-prey equations ($dP/dt = acNP - mP$), under what condition related to prey density would the predator population increase ($dP/dt > 0$)?

Which type of predator functional response (Type 1, 2, or 3) incorporates mechanisms like the development of a 'search image' or prey switching, leading to a lower predation rate at very low prey densities followed by an accelerating rate?

Imagine two species of leaf-mining flies (Calycomyza) that do not directly consume the same resources but are both attacked by the same species of parasitoid wasp. If an increase in the population of fly species A leads to an increase in the parasitoid population, which in turn causes a decrease in the population of fly species B, what type of competitive interaction is occurring between the two fly species?

When plotting population size (y-axis) against time (x-axis), which plot shape is characteristic of a population undergoing exponential growth ($dN/dt = rN$ with $r > 0$)?

When plotting population size (y-axis) against discrete time steps (x-axis), which plot shape is consistent with a geometric growth model ($N_{t+1} = λN_t$) where the finite rate of increase $λ = 1$?

A graph (Plot B) shows logistic population growth. The population initially increases relatively quickly but then levels off smoothly at a density below 300 individuals. Which set of parameters ($r$ = intrinsic growth rate, $K$ = carrying capacity) best describes this pattern?

Consider the Lotka-Volterra competition model equations for two species. What values of the competition coefficients ($α$, representing the per capita effect of species 2 on species 1, and $β$, representing the per capita effect of species 1 on species 2) would cause the model for each species to reduce to the standard single-species logistic growth model?

True or False: The Lotka-Volterra competition model invariably predicts that one species will eventually outcompete and eliminate the other (competitive exclusion).

A figure analyzing the age structure of a white pine forest shows a healthy population of old trees but very few seedlings and saplings that established after the late 1700s. What conclusion does this observation support regarding the white pine population?

Which types of predator functional response curves (Type 1, Type 2, and/or Type 3) exhibit satiation, meaning the predator's consumption rate per capita levels off at high prey densities?

What is a primary limitation of applying Liebig's Law of the Minimum, which states that growth is limited by the single scarcest resource?

Which scenario provides the clearest example of intraspecific competition?

Under what general circumstances does interspecific competition occur?

In population ecology, what does the intrinsic growth rate, often symbolized by 'r', represent?

The rhyme -- 'Red and yellow, kill a fellow; red and black, okay jack!' -- helps distinguish the venomous coral snake from the harmless mimic king snake. The coloration of the non-venomous king snake, which resembles the dangerous coral snake, is an example of what phenomenon?

A graph shows the population size of reindeer introduced to St. Paul Island. The population increased rapidly from 25 individuals, peaked at a very high number far exceeding the island's likely long-term capacity, and then crashed dramatically. Which describe(s) this pattern correctly?

1. The entire pattern closely fits the simple exponential growth model.
2. The population clearly experienced an overshoot phase.
3. The population clearly experienced a subsequent die-off phase.

Briefly explain why microbes, particularly bacteria and archaea, often don't fit well into traditional species concepts (like the biological species concept), and name an alternative model used to define ecologically relevant microbial units.

Describe key ecological factors that interact to influence the abundance of ticks and the risk of Lyme disease transmission in the mid-Atlantic and northeastern US.

A population is censused annually. In year 1, the total population size ($N_1$) is 100. In year 2, the total population size ($N_2$) is 106. Calculate the geometric growth rate (λ) for the period between year 1 and year 2.