Biology Quiz: Intoduction To Ecology!
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If you initially trap and mark 40 iguana in the Sonoran Desert, release them, and later recapture 10 iguana – of which only 2 are marked – then what is the estimated size of the iguana population in this desert?
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400
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800
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200
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100
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50
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Dive into the fundamentals of ecology with our Biology Quiz: Introduction to Ecology! Test your understanding of population dynamics, survivorship curves, carrying capacities, and reproductive strategies. Essential for students preparing for advanced biology exams or anyone interested in ecological science.
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- 2.
What type of survivorship curve is usually associated with organisms that have low mortality in the early stages of life?
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Type I
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Type II
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Type III
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Type IV
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Type V
Correct Answer
A. Type IExplanation
Type I survivorship curve is usually associated with organisms that have low mortality in the early stages of life. This means that these organisms have a high probability of surviving to old age. Type I survivorship curve is characterized by a high survival rate throughout most of the lifespan, with a sharp decline in survival towards the end of life. This curve is commonly observed in large mammals, such as humans, where individuals have a low mortality rate during their early stages of life and a higher mortality rate in old age.Rate this question:
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- 3.
The maximum population size that a particular environment can support is symbolized by _____.
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Rmax
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K
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K – (N/K)
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DN/dt
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(K – N)/K
Correct Answer
A. KExplanation
The correct answer is K. In population ecology, the symbol K represents the carrying capacity of an environment, which is the maximum population size that the environment can support sustainably. It is determined by factors such as available resources, space, and competition. When the population size reaches or exceeds the carrying capacity, it can lead to resource depletion and other negative impacts on the environment. Therefore, K represents the maximum limit that the population can reach without causing detrimental effects.Rate this question:
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- 4.
Logistic population growth is represented by dN/dt = _________.
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RK [N-K/N]
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RN [(K - N)/K]
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RN-K [(K - N)/K]
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RN/[K-N]
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RN [(N - K)/N]
Correct Answer
A. RN [(K - N)/K]Explanation
The logistic population growth equation represents the rate of change of population size over time. In this equation, "dN/dt" represents the rate of change of population size, "r" represents the intrinsic growth rate of the population, "N" represents the current population size, and "K" represents the carrying capacity of the environment. The term "(K - N)/K" in the equation indicates the proportion of available resources that are not being utilized by the population, and multiplying it by "rN" gives the rate at which the population can grow. Therefore, the correct answer is "rN [(K - N)/K]".Rate this question:
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- 5.
Which of the following best describes a species that exhibits iteroparous reproduction?
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It exhibits “big bang” reproduction.
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It reproduces with the same mate every time, if possible.
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It reproduces with several mates per breeding season.
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It reproduces multiple times over the course of its lifetime.
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It can be an adaptation to a variable environment.
Correct Answer
A. It reproduces multiple times over the course of its lifetime.Explanation
Iteroparous reproduction refers to the ability of a species to reproduce multiple times over its lifetime. This means that individuals of the species can have multiple breeding seasons and produce multiple offspring throughout their lives. This is in contrast to semelparous reproduction, where individuals only reproduce once in their lifetime. Iteroparous reproduction can be advantageous in a variable environment because it allows for the production of offspring in multiple breeding seasons, increasing the chances of survival and successful reproduction.Rate this question:
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- 6.
Which is true of carrying capacity?
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it increases as the per capita growth rate decreases
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It remains constant over time
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It can never be exceeded
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It may change as environmental conditions change
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It can be calculated using the exponential growth model
Correct Answer
A. It may change as environmental conditions changeExplanation
Carrying capacity refers to the maximum number of individuals that a particular environment can sustainably support. This capacity is not fixed and can change depending on the environmental conditions. Factors such as availability of resources, competition, predation, and disease can all influence the carrying capacity of a population. Therefore, the statement "it may change as environmental conditions change" accurately describes the nature of carrying capacity.Rate this question:
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- 7.
Abiotic factors as well as biotic are considered more so when studying which type of ecological system?
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A population
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A community
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An ecosystem
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A habitat
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A species' life history
Correct Answer
A. An ecosystemExplanation
When studying an ecosystem, both abiotic factors (non-living components like temperature, water availability, and soil type) and biotic factors (living organisms like plants, animals, and microorganisms) are considered. This is because an ecosystem is a complex system where the interactions between the living and non-living components determine the overall functioning and dynamics of the system. Understanding the interplay between abiotic and biotic factors is crucial for comprehending the ecological processes and relationships within an ecosystem. Therefore, the correct answer is an ecosystem.Rate this question:
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- 8.
In a population undergoing logistic growth, ____.
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The death rate decreases as N gets close to K
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The population growth rate increases when N gets close to K
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DN/dt is minimized as N gets close to K
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The per capita rate of increase rises as N gets close to K
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The population grows exponentially when K is small
Correct Answer
A. DN/dt is minimized as N gets close to KExplanation
In a population undergoing logistic growth, the rate of change of population size (dN/dt) is minimized as the population size (N) gets close to the carrying capacity (K). This is because as the population approaches its carrying capacity, there is less room and resources available for growth, causing the growth rate to slow down and eventually reach a plateau. Therefore, the rate of change of population size is minimized when the population size is close to the carrying capacity.Rate this question:
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- 9.
In a population undergoing exponential growth, _____.
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Birth rates and death rates are equal
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The rate of population growth increases with added resources
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The number of individuals in a population has no effect on the rate of population growth
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The per capita rate of increase is constant
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The intrinsic rate of increase depends on the resource availability
Correct Answer
A. The per capita rate of increase is constantExplanation
In a population undergoing exponential growth, the per capita rate of increase is constant. This means that for each individual in the population, the rate at which the population is growing remains the same over time. This is because in exponential growth, each individual has the potential to produce offspring at a constant rate, leading to a consistent increase in the population size. The per capita rate of increase is not affected by the number of individuals in the population or the availability of resources.Rate this question:
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- 10.
Which of the following is an example of a biotic factor in ecological studies?
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Soil acidity
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Solar radiation
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Salinity
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Density
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Precipitation
Correct Answer
A. DensityExplanation
Density is an example of a biotic factor in ecological studies because it refers to the number of individuals of a species within a given area. Biotic factors are living components of an ecosystem, and density specifically relates to the population size and distribution of organisms. It can affect various ecological processes such as competition for resources, predation, and disease transmission.Rate this question:
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- 11.
Which of the following is the most likely life-history that you would observe in a species?
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A. production of many young annually over the course of a long lifetime
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B. production of few young in a single bout of reproduction per lifetime
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C. production of many young once and then dying
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D. choices A and B apply
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E. choices A and C apply
Correct Answer
A. C. production of many young once and then dyingExplanation
This life-history strategy, known as semelparity, is commonly observed in species that have a short lifespan and high mortality rate. These species invest a significant amount of energy in producing a large number of offspring in a single reproductive event, with the expectation that only a few will survive to reproduce. Once they have reproduced, they typically die shortly after. This strategy is advantageous in unstable or unpredictable environments where survival rates are low and resources are limited.Rate this question:
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- 12.
Which of the following would not contribute demographic data about a population of squirrels?
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The type of food they eat
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The number of times they reproduce per year
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The average number of young born to mating pairs
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The number of individuals & their age
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The number of females as opposed to males
Correct Answer
A. The type of food they eatExplanation
The type of food squirrels eat does not provide demographic data about a population of squirrels. Demographic data typically includes information about reproduction rates, population size and age structure, and gender distribution. While the type of food may impact the overall health and behavior of the population, it does not directly contribute to demographic data.Rate this question:
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- 13.
______________ is not a density-dependent growth factor.
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Food
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Nesting sites
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Fluctuations in weather
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Physiological responses to crowding
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Nutrient and mineral resources
Correct Answer
A. Fluctuations in weatherExplanation
Fluctuations in weather do not directly affect the population density of organisms, unlike the other factors listed. Food availability, nesting sites, physiological responses to crowding, and nutrient and mineral resources all play a role in determining population density and growth. However, weather fluctuations such as changes in temperature or rainfall do not directly depend on population density and therefore do not act as density-dependent growth factors.Rate this question:
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- 14.
Which of the following levels of organization is arranged in the correct sequence from most inclusive (i.e., broadest) to least inclusive?
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Community, ecosystem, individual, population
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Individual, population, community, ecosystem
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Population, ecosystem, individual, community
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Ecosystem, community, population, individual
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Individual, community, population, ecosystem
Correct Answer
A. Ecosystem, community, population, individualExplanation
The correct answer is ecosystem, community, population, individual. This sequence is arranged in a hierarchical order starting from the broadest level of organization, which is the ecosystem. The ecosystem includes all living organisms and their physical environment in a specific area. Within the ecosystem, there are different communities, which are groups of different species interacting with each other. Within each community, there are populations, which are groups of individuals of the same species. Finally, at the least inclusive level, there are individuals, which are single organisms of a particular species.Rate this question:
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- 15.
In the logistic equation dN/dt = rN, ((K - N)/K), r is a measure of the population's intrinsic rate of increase. It is determined by which of the following?
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A. death rate
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B. birth rate
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C. density
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D. A and B only
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E. A, B, and C
Correct Answer
A. D. A and B onlyExplanation
The correct answer is D. A and B only. In the logistic equation, the term "r" represents the population's intrinsic rate of increase. This rate is determined by both the birth rate and the death rate. The birth rate represents the number of individuals being born into the population, while the death rate represents the number of individuals dying from the population. Therefore, both the birth rate and the death rate contribute to the population's intrinsic rate of increase. Density, on the other hand, is not directly related to the intrinsic rate of increase in the logistic equation.Rate this question:
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- 16.
In models of sigmoidal (logistic) population growth, _______.
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A) new individuals are added to the population most rapidly at intermediate population sizes.
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B) density-dependent factors affect the rate of population growth.
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C) population growth rate slows dramatically as N approaches K.
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D) All of the above are true.
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E) Only A and C are true.
Correct Answer
A. D) All of the above are true.Explanation
In models of sigmoidal (logistic) population growth, new individuals are added to the population most rapidly at intermediate population sizes. This is because at low population sizes, there may be limited resources or mating opportunities, while at high population sizes, competition for resources may increase and limit the rate of population growth. Density-dependent factors, such as competition for resources or predation, affect the rate of population growth. As the population size approaches the carrying capacity (K), the population growth rate slows dramatically because resources become limited and competition increases. Therefore, all of the statements A, B, and C are true in models of sigmoidal population growth.Rate this question:
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- 17.
The sum total of an organism's interaction with the biotic and abiotic resources of its environment is called its ________.
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Biological potential
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Ecological niche
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Logistic growth
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Habitat
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Microclimax
Correct Answer
A. Ecological nicheExplanation
The term "ecological niche" refers to the sum total of an organism's interaction with the biotic and abiotic resources of its environment. It encompasses the specific role and position that an organism occupies within its ecosystem, including its habitat, food sources, interactions with other organisms, and its overall function in the ecosystem. This concept helps to understand how different species coexist and adapt to their environment, as each species has its own unique niche that allows it to survive and thrive.Rate this question:
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- 18.
Resource partitioning would be most likely to occur between ______.
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Sympatric populations of species with similar ecological niches.
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Sympatric populations of a predator and its prey.
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Allopatric populations of species with similar ecological niches.
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Allopatric populations of the same animal species.
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Sympatric populations of a flowering plant and its specialized insect pollinator.
Correct Answer
A. Sympatric populations of species with similar ecological niches.Explanation
Resource partitioning refers to the division of limited resources among competing species in order to reduce competition. It is most likely to occur between sympatric populations of species with similar ecological niches because they occupy the same geographic area and have similar resource requirements. This competition for resources can lead to the evolution of different traits or behaviors that allow each species to utilize different resources and coexist in the same habitat.Rate this question:
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- 19.
An insect that has evolved to resemble a plant twig will probably be able to avoid ______.
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Parasitism
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Predation
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Symbiosis
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Commensalism
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Competition
Correct Answer
A. PredationExplanation
An insect that has evolved to resemble a plant twig will probably be able to avoid predation. This is because the insect's resemblance to a plant twig helps it blend in with its surroundings, making it difficult for predators to detect and capture it. By avoiding predation, the insect increases its chances of survival and reproductive success.Rate this question:
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- 20.
Which of the following is an example of Batesian mimicry?
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A butterfly that resembles a leaf
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An insect that resembles a twig
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A nonvenomous snake that looks like a venomous snake
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A fawn with fur coloring that camouflages it in the forest environment
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A snapping turtle that uses its tongue to mimic a worm, thus attracting fish
Correct Answer
A. A nonvenomous snake that looks like a venomous snakeExplanation
An example of Batesian mimicry is when a harmless or nonvenomous species mimics the appearance of a harmful or venomous species to deter predators. In this case, a nonvenomous snake that looks like a venomous snake is an example of Batesian mimicry. By resembling a venomous snake, the nonvenomous snake is able to avoid being preyed upon by predators who would otherwise avoid the venomous snake.Rate this question:
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- 21.
Which of the following is an example of aposematic coloration?
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A katydid whose wings look like a dead leaf
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Eye color in humans
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Green color of a plant
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Colors of an insect-pollinated flower
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Stripes of a skunk
Correct Answer
A. Stripes of a skunkExplanation
Aposematic coloration is a defensive mechanism in which an organism uses bright or striking colors to warn potential predators that it is toxic or dangerous. The stripes of a skunk serve as an example of aposematic coloration because they are highly visible and act as a warning signal to other animals, indicating that the skunk possesses a potent defensive weapon in the form of its foul-smelling spray.Rate this question:
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- 22.
Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes and is not harmed by them. Which of the following best describes the interactions between dwarf mistletoes and trees?
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facilitation
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Mutualism
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Parasitism
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Commensalism
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Competition
Correct Answer
A. CommensalismExplanation
Dwarf mistletoes and trees have a commensalistic relationship. The dwarf mistletoes benefit from the trees by obtaining nutrients and water from their vascular tissues, while the trees are not harmed or benefited in any known way. This interaction is considered commensalism because one species (dwarf mistletoes) benefits while the other (trees) is unaffected.Rate this question:
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- 23.
Which of the following are important biotic factors that can affect the structure and organization of biological communities?
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Light intensity, seasonality
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Precipitation, wind
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Temperature, water
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Nutrient availability, soil pH
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Predation, competition
Correct Answer
A. Predation, competitionExplanation
Predation and competition are important biotic factors that can affect the structure and organization of biological communities. Predation refers to the interaction where one organism (predator) hunts and consumes another organism (prey), which can influence the population sizes and dynamics of both predator and prey species. Competition occurs when different organisms compete for limited resources such as food, water, or shelter, which can lead to the exclusion of certain species or the coexistence of species with different resource requirements. Both predation and competition play crucial roles in shaping community structure and determining the abundance and distribution of species within a community.Rate this question:
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- 24.
Which of the following would be most likely to exhibit uniform dispersion?
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dwarf mistletoes, which parasitize particular species of forest trees
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Lake trout, which seek out deep water
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Cattails, which grow primarily at edges of lakes and streams
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Red squirrels, which hide food and actively defend territories
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A field of annual poppies
Correct Answer
A. Red squirrels, which hide food and actively defend territoriesExplanation
Red squirrels, which hide food and actively defend territories, would be most likely to exhibit uniform dispersion because they actively defend their territories and hide their food, which leads to an even distribution of individuals throughout the habitat. This behavior reduces competition for resources and increases the chances of survival for each individual.Rate this question:
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- 25.
If you were to keep records on a cohort of wild animals for the purpose of developing a life table, you would be most successful if you chose to keep records on _______.
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Wolves in a national park
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Earthworms in a backyard
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pelagic squid (pelagic = living throughout the open ocean)
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Migratory birds
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Mosquitoes
Correct Answer
A. Wolves in a national parkExplanation
Keeping records on wolves in a national park would be most successful for developing a life table because wolves are large mammals that typically have longer lifespans and slower reproductive rates compared to other animals listed. This would allow for more accurate and reliable data collection over a longer period of time. Additionally, national parks often provide protected habitats and resources for wolf populations, which can contribute to their overall population stability and survival.Rate this question:
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- 26.
Which of the following is an incorrect statement about the regulation of populations?
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High densities in a population may cause physiological changes that inhibit reproduction
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The effect of density-dependent factors is more predictable than the effect of density-independent factors
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The growth of a population of individuals with high fitness is a combination of density-dependent and density- independent factors
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The logistic equation reflects the effect of density-dependent factors, which can ultimately stabilize populations around the carrying capacity
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Density-independent factors have an increasingly greater effect as a population's density increases
Correct Answer
A. Density-independent factors have an increasingly greater effect as a population's density increasesExplanation
Density-independent factors have an increasingly greater effect as a population's density increases. This statement is incorrect because density-independent factors are not influenced by population density. These factors, such as natural disasters or climate changes, affect population growth and mortality rates regardless of population density.Rate this question:
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- 27.
Logistic growth of a population is represented by _________.
Correct Answer
dN/dt = rN [(K-N)/K]Explanation
The given equation dN/dt = rN [(K-N)/K] represents the logistic growth of a population. This equation takes into account the rate of change of population (dN/dt) over time, which is proportional to the current population size (N). The term [(K-N)/K] represents the carrying capacity (K) of the environment, indicating how much the population can sustainably grow. The logistic growth model incorporates both exponential growth (rN) and a limiting factor (K-N), resulting in a sigmoidal growth curve that levels off as the population reaches its carrying capacity.Rate this question:
- 28.
As N approaches K for a certain population, which of the following is predicted by the logistic equation?
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The carrying capacity of the environment will increase
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The population will increase exponentially
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The population will crash
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The growth rate will slow and approach zero
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The growth rate will not change
Correct Answer
A. The growth rate will slow and approach zeroExplanation
As N approaches K in the logistic equation, it means that the population is approaching its carrying capacity. The logistic equation models population growth that eventually levels off as resources become limited. Therefore, the correct prediction is that the growth rate will slow down and approach zero as the population nears its carrying capacity. This is because the available resources cannot support unlimited growth, causing the growth rate to decrease and eventually reach a stable point.Rate this question:
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- 29.
Which of the following is an example of an intrinsic density-dependent factor that can act to regulate population growth?
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Food availability
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Intraspecific aggression
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toxin accumulation
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An increase in predation rates as prey density increases
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A sustained drought
Correct Answer
A. Intraspecific aggressionExplanation
Intraspecific aggression is an example of an intrinsic density-dependent factor that can regulate population growth. This refers to aggression between individuals of the same species, which can occur when population density increases. As the population becomes more crowded, competition for resources such as food, territory, or mates intensifies, leading to increased aggression. This aggression can result in injury or death, which can limit population growth. Therefore, intraspecific aggression is a mechanism by which population size can be regulated in response to changes in density.Rate this question:
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- 30.
A group of individuals born at the same time is known as a _______.
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Cohort
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Subpopulation
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Subspecies
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Deme
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Population
Correct Answer
A. CohortExplanation
A group of individuals born at the same time is known as a cohort. This term is commonly used in social sciences and refers to a group of people who share a particular characteristic or experience, such as being born in the same year or belonging to the same generation. It helps researchers study and understand how individuals within a cohort may be influenced by similar factors or events throughout their lives.Rate this question:
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- 31.
A demographer studying a population of a particular organism would be least likely to be engaged in which of the following?
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Sampling the population and determining the sex ratio
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constructing a life table for the organism
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Estimating how long an individual of a given age will live
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Measuring birth and death rates
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Studying predatory behavior
Correct Answer
A. Studying predatory behaviorExplanation
A demographer studying a population of a particular organism would be least likely to be engaged in studying predatory behavior because the focus of demography is on the statistical study of populations, including factors such as birth rates, death rates, sex ratio, and life expectancy. Predatory behavior is more related to the study of ecology and behavior rather than population dynamics.Rate this question:
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- 32.
In a population in which offspring survival is quite low and the environment is inconsistent, one might expect _____.
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the production of a large number of large offspring
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The production of a small number of large offspring
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Semelparity or big-bang reproduction
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Parents delaying reproduction until population size reaches carrying capacity
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Iteroparity or repeated reproduction with a small number of offspring
Correct Answer
A. Semelparity or big-bang reproductionExplanation
In a population with low offspring survival and inconsistent environment, it would be advantageous for individuals to produce a large number of large offspring. This strategy increases the chances of at least some offspring surviving and reproducing in the unpredictable environment. However, the correct answer is semelparity or big-bang reproduction. This is because in such conditions, it may be more beneficial for individuals to reproduce only once in their lifetime, producing a large number of offspring all at once. This ensures that at least some offspring have a chance of surviving and reproducing before the environment becomes unfavorable again.Rate this question:
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- 33.
Which of the following might be expected in the logistic model of population growth?
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A) As N approaches K, death rate increases.
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B) As N approaches K, birth rate increases.
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C) As N approaches K, r increases.
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D) Both A and B are true.
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E) Both B and C are true.
Correct Answer
A. A) As N approaches K, death rate increases.Explanation
As the logistic model of population growth approaches the carrying capacity (K), the population size (N) becomes closer to the maximum sustainable population that the environment can support. In this scenario, limited resources and competition for those resources may increase, leading to a higher death rate. This is because as the population size approaches the carrying capacity, there may not be enough resources to sustain the entire population, resulting in increased mortality. Therefore, option A) As N approaches K, death rate increases, is a reasonable expectation in the logistic model of population growth.Rate this question:
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- 34.
Density-independent factors have an increasingly greater effect as a population's density increases.
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True
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False
Correct Answer
A. FalseExplanation
Density-independent factors do not have an increasingly greater effect as a population's density increases. Density-independent factors, such as natural disasters or climate events, have the same effect on a population regardless of its density. These factors are not influenced by the size or density of a population and can affect individuals in a population equally, regardless of how crowded or sparse the population is. Therefore, the given statement is false.Rate this question:
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- 35.
The logistic equation reflects the effect of density-independent factors, which can ultimately stabilize populations around the carrying capacity.
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True
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False
Correct Answer
A. FalseExplanation
The logistic equation does not reflect the effect of density-independent factors. Instead, it takes into account density-dependent factors such as competition for resources, predation, and disease, which can ultimately stabilize populations around the carrying capacity.Rate this question:
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- 36.
Which of the following aspects of a bird’s life is least relevant in describing its life history?
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A) age at which it first reproduces
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B) duration of migration
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C) frequency of reproduction
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D) number of offspring per reproductive bout
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E) all of the above are equally relevant
Correct Answer
A. B) duration of migrationExplanation
The duration of migration is least relevant in describing a bird's life history because it is a specific behavior that some bird species engage in during certain times of the year, but it does not necessarily impact their overall life history. Other aspects such as the age at which they first reproduce, the frequency of reproduction, and the number of offspring per reproductive bout are more directly related to the bird's life history and reproductive success.Rate this question:
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- 37.
A small population of squirrels has the same intrinsic rate of increase (rmax) as a large population. If everything else is equal _____.
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the J-shaped growth curves will look identical
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The growth trajectories of the two populations will proceed in opposite directions
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The two populations will add equal numbers of individuals per unit time
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the large population will add more individuals per unit time
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the small population will add more individuals per unit time
Correct Answer
A. the large population will add more individuals per unit timeExplanation
If everything else is equal and the small population of squirrels has the same intrinsic rate of increase (rmax) as a large population, the large population will add more individuals per unit time. This is because the larger population has a greater number of individuals available to reproduce, leading to a higher absolute number of individuals being added over a given time period.Rate this question:
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Aug 03, 2011Quiz Created by
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