Biology 1407 ch.54 Flashcards
Which of the following is a limiting factor in the production of large families of offspring?
In many bird species, an increase in the production of offspring in one year results in which of the following?
An increase in the probability of dying during that same year
A decrease in the number of offspring produced the following year
Organisms allocate __________ to current reproduction, or to increasing their prospects of surviving and reproducing at a later time.
Choose increase or decrease for each blank. In some organisms, an (Blank 1) in reproduction leads to a (Blank 2), and consequently, a (Blank 3) in the number of offspring produced in the future.
Blank 1: increase
Blank 2: decrease
Blank 3: decrease or reduction
Which of the following accurately describes the cost of reproduction?
A reduction in future reproduction as a result of current reproductive efforts
When are organisms expected to produce as many offspring as possible?
When the cost of reproduction is low
Which of the following are true concerning the number of offspring produced per reproductive effort and the investment in offspring per reproductive effort?
Production of fewer offspring during a reproductive event results in larger offspring with a greater chance of survival.
A balance is required between the number of offspring produced and the size of each offspring.
The more offspring is produced during a reproductive event, the less energy is invested per offspring.
Ecologists refer to the reduction in future reproductive potential resulting from current reproductive efforts as the (Blank 1) of (Blank 2)
Blank 1: cost
Blank 2: reproduction
When the cost of reproducing is high, organisms often
allocate resources to survival and minimize reproduction.
defer reproduction to enhance growth.
The number of offspring produced during a single reproductive event
affects the investment in offspring, and the size of each offspring.
What is semelparity?
Semelparity is a reproductive pattern in which the organism reproduces one time and dies.
Iteroparity refers to which of the following?
Animals reproduce throughout their lifetimes.
A reproductive strategy in which the organism produces all their offspring in a single reproductive event is called
A(n) ______ reproductive strategy is one in which an organism exhibits a pattern of repeated reproduction at intervals throughout its lifetime.
Animal species that have (Blank 1) life spans typically reproduce later in life in comparison to animals species that have (Blank 2) life spans.
Blank 1: longer
Blank 2: shorter
Which of the following accurately describes a major advantage of delayed reproduction in longer-lived animal species?
Juveniles are able to gain experience before investing energy in reproduction.
A major source of limitation for population (Blank 1) is the fact that some individuals have fewer surviving offspring than others.
Blank 1: growth
Which of the following is true of animal species which are longer-lived?
They reproduce at an older age than short-lived species.
A major advantage of (Blank 1) reproduction among longer-lived mammals is that offspring gain experience before the energy expenditure of reproduction.
Blank 1: delayed
Which of the following best describes why populations remain at a relatively constant size regardless of how many offspring are born?
Some individuals have fewer surviving offspring than others.
Which of the following equations is used to calculate the rate of population increase?
The (Blank 1) (Blank 2) is the rate at which a population of a given species increases when no limits are placed on its rate of growth.
Blank 1: biotic
Blank 2: potential
In the equation r = (b-d) + (i-e), r is used to identify which of the following?
Rate of population increase
Which of the following assumptions would be made when modeling exponential growth?
Food is plentiful.
Space is available.
Water is unlimited.
Which of the following best describes biotic potential?
The rate at which a population grows when no limits are placed on its rate of growth
Rapid population growth occurring when per capita growth rate remains above zero is called (Blank 1) growth.
Blank 1: exponential
Which of the following best describes the result of unchecked exponential growth?
In this figure, line A represents (Blank 1), whereas line B represents (Blank 2).
Blank 1: growth
Blank 2: logistic
The pattern in which population growth slows down as it approaches the carrying capacity is termed (Blank 1) growth.
Blank 1: logistic
(Blank 1) growth models assume resources are unlimited.
Blank 1: Exponential
What is exponential growth?
Rapid growth with a constant rate of increase
Unchecked (Blank 1) growth of a population can result in a population explosion which would theoretically continue infinitely.
Blank 1: exponential
What does rN represent in the logistic growth model?
Intrinsic rate of increase
The sigmoidal growth curve in this figure represents which of the following models of population growth?
In which of the following situations would a population exhibit exponential growth?
A population which reaches a new habitat with an abundance of resources
Which of the following describes logistic growth?
Logistic growth occurs when the population is restricted by some limiting factor.
The carrying capacity is defined as
the maximum number of individuals that an environment can sustain.
Population growth cannot continue at the maximum rate forever because of the limited amount of (Blank 1) available in the environment. Population growth slows and stabilizes at a size called the (Blank 2) (Blank 3) because of these limits.
Blank 1: resources
Blank 2: carrying
Blank 3: capacity
In the logistic growth model, (K-N)/K represents
the fraction of the carrying capacity that is still unused.
Which of the following best describe how/when patterns of unrestrained or exponential growth of populations generally occur?
For short periods of time
A reduction in the amount of available resources in an environment would cause the carrying capacity to
Which of the following accurately describe why populations cannot grow exponentially forever?
Population growth is limited by the amount of available resources.
A population with a per capita growth rate declining to zero would begin to approach its
Blank 1: max
Blank 2: capacity
When a population's size does not change over time, the population's growth rate is
Density-(Blank 1) factors are those whose influence varies with population density, whereas density-(Blank 2) factors are those whose influence is unaffected by population size.
Blank 1: dependent
Blank 2: independent
Which of the following can be affected by density dependent factors?
Death rates and/or birth rates
Which of the following describe what happens to a population as it approaches its carrying capacity?
As a population approaches carrying capacity, resources are used up and growth rate declines.
According to the logistic growth model, when the number (N) of individuals in a population approaches its carrying capacity (K), the population's growth rate should approach (and eventually become) which of the following?
Which of the following accurately compares density dependent (DD) factors and density independent (DI) factors?
DD: mortality increases with population size; DI mortality remains unchanged with population size
Choose all ways in which density dependent effects can limit population growth.
Increased levels of predation
Accumulation of toxic wastes
Strong competition for resources.
Choose the two examples of populations that might exhibit the Allee effect.
A sparsely distributed population, in which individuals have difficulty finding mates
A population of a species that relies on large groups to deter predators
Which of the following describes the role of density-dependent factors on population size?
Density-dependent factors regulate population size by limiting growth as density increases.
Which of the following accurately defines density-independent mortality factors?
Factors for which mortality remains unchanged in response to population density
Which of the following is an example of a density-dependent factor?
Select all of the following that are density-independent factors that influence population size.
In some cases, the growth rate of a population can increase with population size. This is known as the (Blank 1) effect.
Populations strongly affected by density-independent factors often time exhibit
erratic growth patterns.
Mortality factors whose influence is not affected by changes in the number of individuals per unit are called density-(Blank 1) factors.
Blank 1: independent
Which of the following is a density-independent factor?
What two factors appear to regulate the numbers of snowshoe hares?
What type of factors can produce a population growth curve characterized by erratic growth patterns?
Which of the following accurately describe the following features of a typical K-selected species?
A. LIfe span
B. Mortality rate
C. Size of offspring
A. Long; B. Usually low; C. Large
K-selected species would include which of the following?
Which of the following is an r-selected species?
Population cycles for the Snowshoe hare are regulated by two factors, (Blank 1) and (Blank 2).
Blank 1: predators
Blank 2: food or food plants
(Blank 1)-selected species are those with unstable populations that have a high rate of per capita population growth.
(Blank 1)-selected species are those with relatively stable populations adapted to existing at or near their carrying capacity.
Which of the following are considered K-selected species?
Which of the following are r-selected species?
Characteristics of r-selected species include which of the following?
High reproductive rate
Early reproductive age
(Blank 1)-selected species exhibit high per capita growth rates with poor competitive ability, whereas (Blank 2)-selected species exhibit low per capita growth rates with strong competitive ability.
Blank 1: r
Blank 2: K
Humans exhibit which of the following K-selected adaptations?
Long life span
What type of species would be expected to have a short life span, and an early age at first reproduction?
An r-selected species
Which of the following best describes how the human population is growing?
It is growing exponentially because of advancements in technology.
The current growth rate of the human population is about
1.1% per year
Which of the following are K-selected life-history traits seen in humans?
High degree of parental care
Small brood size
What are r-selected species?
Species with high rate of per capita population growth, but poor competitive ability
In most human population pyramids,
the number of older females is disproportionately large compared with the number of older males.
Which of the following is true of a population pyramid that has a triangular shape?
It has a large number of people below child-bearing age; it will experience rapid future population growth when these people have children.
Select all reasons for human exponential growth.
Improvements to public health
Better sanitation practices
Domestication of animals
The current growth rate of the human population is 1.1% per year. What does this growth rate mean in terms of the doubling time of the human population?
It will still take relatively little (about 60 years) for the human population to double
A population (Blank 1) is a bar graph displaying the number of people in several age categories.
A population pyramid that is shaped like an (Blank 1) triangle is characteristic of a shrinking population
Blank 1: inverted
Rapid population growth in developing countries has had an important effect: it has increased the gap between
the rich and the poor.
As the human population approaches Earth's carrying capacity, scientists have recorded
an increase in death rates in some areas of the planet.
The human growth rate is currently (Blank 1) due to increased family planning methods, and the increase economic power and social status of women.
Recently, the gap between the rich and the poor has significantly increased in many developing countries. This is at least to some extent due to
the rapid growth of the human population in those countries.
What proportion of the human population is currently malnourished?
Between 1/4 and 1/8
The aggregate total of productive land needed for survival is called a person's (Blank 1)(Blank 2)
Blank 1: ecological
Blank 2: footprint
Which of the following factors have led to a decline in the world population growth rate?
Increase in availability of family planning programs
How does the ecological footprint of an individual in the USA compare to that of someone in a developing country, such as, for example, India?
The ecological footprint of someone in the USA is much larger.
Which of the following accurately describes an ecological footprint?
The amount of land required to support an individual throughout their lifetime
If the average ecological footprint per person that Earth can sustain is about 2 hectares and humans exceed that, an ecologist would infer which of the following?
We were in an ecological deficit and we would reach carrying capacity faster.
How does the ecological footprint of individuals in developed countries compare to that of individuals in developing countries?
Developed countries >> developing countries
Our ecological footprint can help estimate carrying capacity because of which of the following?
It is an indication of whether we are using more productive land than the earth can sustain over time.