bio, chap 14

The age-structure diagram of a human population in a developing country has the shape of:

a pyramid

population ecology

a subfield of ecology that focuses on populations of organisms of a species and how they interact with the environment

Approximately what is the current size of the human population? a) 6.7 billion b) 10.1 billion c) 5.8 billion d) 900 million e) 2.2 billion

a) 6.7 billion

Which statement best describes expectations for world human population by the year 2010?

It will exceed 7 billion if the current rate of increase continues.

A population of meadow voles has an annual per capita birth rate of 0.08 and an annual per capita death rate of 0.02. Estimate the number of individuals added to or lost from a population of 1000 individuals in one year. a) 40 individuals lost b) 80 individuals added c) 20 indivdiuals lost d) 20 individuals added e) 60 individuals added

e) 60 individuals added

Which of the following assumptions of logistic growth is NOT CORRECT for most populations? a) Immigration and emigration rates are zero for the population. b) Every individual has its effect on the population and resources beginning at birth. c) Every individual has an equal effect on the population and resources. d) Both birth and death rates remain continuous. e) All of the above are NOT CORRECT for most populations.

e) All of the above are NOT CORRECT for most populations.

exponential growth

occurs when each individual produces more than the single offspring necessary to replace itself. -usually J-shaped when on graph

number and size of offspring life trade-off

female lizards of the species Uta stansburiana produce medium-size eggs as a compromise between a large number of small eggs and a few large eggs

Which factor would MOST LIKELY influence an environment's carrying capacity for field mice?

food supply

survivorship curves

graphs showing the proportion of individuals of a particular age that are now alive in the population

Type III

high mortality early in life, but those the survive the early years live long lives

Type I

high survivorship until old age, then rapidly decreasing survivorship

maximum sustainable yield

in which as many individuals from a population are removed without impairing its growth

when a population is half way to the carrying capacity

it is at its fastest growth rate

by increasing the strength of natural selection later in life

it is possible to increase the mean and maximum longevity of individuals in a population

When the hazard factor is low, individuals tend to reproduce:

later in life

density-limitation factors

limitations that are due to size of population in area

As population size increases, the individuals within the population generally experience all of the following EXCEPT:

more difficulty in finding mates.

alleles that cause sickness and death later in life

mutations that cause sickness and death after reproduction will be passed to future generations

alleles that cause sickness and death early in life

natural selection "weeds out" alleles that cause sickness and death early in life, because those alleles never get passed on

A life table:

predicts survival and mortality rates for an individual at a given age.

Ecology is studied at many levels which include:

-Individuals- individual organisms -Populations- groups of individual organisms that interbreed with each other -communities- populations of different species that interact with each other within a locale -ecosystems- all living organisms, as well as non-living elements, that interact in a particular area

three types of survivorship curves:

-Type I -Type II -Type III

the carrying capacity for the human population is difficult to estimate is that we can increase it in a variety of ways through:

-expanding into new habitats with fire, shelter, and efficient food distribution, we can survive almost anywhere on earth -increasing the agricultural productivity of the land with fertilizers, mechanized agricultural methods, and selection for higher yields, fewer people can now produce much more food than previously thought possible -finding ways to live at higher densities public health and civil engineering advances make it possible for higher and higher densities of people to live together with minimal problems from waste and infectious diseases

locusts increase rapidly in population sometimes due to:

-good rain -mild temperatures

fast, intensive reproductive investment

-reaches sexual maturity at one month -produces litters of six to ten offspring every month

Big-Bang reproduction

-reaches sexual maturity at one year -mates intensely over a three-week period -males die shortly after mating period -females usually die after weaning their first litter

slow, gradual reproductive investment

-reaches sexual maturity at one year -produces about one offspring each year

as population size increase, organisms experience:

-reduced food supplies, due to competition -diminished access to places to live and breed, also due to competition -increased incidence of parasites and disease, which spread more easily when their hosts live at a higher density -increased predation rate, as predator populations grow in response in response to the increased availability and visibility of prey

animals with high hazard factor:

-relatively high risk of death at each age -individuals tend to reproduce earlier -earlier aging -shorter life spans e.g. mouse

animals with low hazard factor:

-relatively low risk of death at each age -individuals tend to reproduce later -later aging -longer life spans

population oscillations

1) a growing prey population provides more food for the predator population, which then reproduce at a higher rate 2) predators eat too many prey, thereby reducing the prey population which reduces the predator population which allows the prey population to grow again

Demographic transition is characterized by:

1)slow growth populations with inefficient systems of food production and distribution, along with a lack of reliable medical care, usually have high birth rates and death rates, leading to slow population growth 2)fast growth as industrialization begins, both food production and health care improve, leading to a reduction in the death rate. The birth rate remains relatively high, and so the country's population grows rapidly 3)slow growth as industrialization continues, the birth rate decreases as a result of higher levels of education and employment, along with improved healthcare. the new, lower birth rate that slows the population's growth

The 20 female adults in a small population each have a probability of 0.5 of producing a single offspring each year and a probability of 0.5 of producing no offspring. How many female offspring will be produced each year?

10 offspring per year on average, with some variation around this average

If r = 5 for a population at a given time (t) when N = 100, what will the population size be at time t+2 (two generations later)?

2,500

Life histories are based on

ALL THE ABOVE a) the time that it takes for an organism to mature. b) the age at death. c) the rate of growth and development. d) the age of reproduction and number of reproductive events. e) All of the above are correct.

In a population exhibiting logistic growth, what happens when the carrying capacity is exceeded?

The growth rate becomes negative until the population in back within the carrying capacity.

logistic growth

describes population growth that is gradually reduced as the population near's the environment's carrying capacity

ecological footprint

a measure of the impact of an individual or population on the environment by calculations of the amount of resources-including land, food and water, and fuel-consumed

demographic transition

a pattern of population growth that is experienced as a country industrializes.

f there are 500 individuals in a population at the start of a year, and during the year 125 offspring are produced in that population, then the annual birth rate is: a) .25 b) 1.25 c) 125 d) .5 e) The annual birth rate cannot be computed from the information provided.

a) .25

What may happen when a population exceeds its carrying capacity? a) The population will slowly decline until it reaches its carrying capacity and fluctuate about that number. b) The level of resources in the habitat will increase equally. c) Populations cannot exceed their carrying capacity. d) The carrying capacity is increased. e) Both a) and b) are correct

a) The population will slowly decline until it reaches its carrying capacity and fluctuate about that number.

Disease is spread more quickly between individuals who live in close proximity, such as in a nesting colony of penguins. Disease can be considered a: a) density-dependent factor. b) factor that causes a greater birth rate than death rate. c) exponential growth factor. d) factor that increases carrying capacity. e) density-independent factor.

a) density-dependent factor.

When plants of a particular species are growing too close to each other, crowding may eventually lead to mortality, known as self-thinning. This type of mortality is: a) density-dependent. b) exponential. c) oscillating. d) biotic potential. e) density-independent.

a) density-dependent.

When a population grows in proportion to its current size (e.g. bigger populations grow faster), that population is experiencing ________ growth. a) exponential b) density-dependent c) logistic d) density-independent e) capacity

a) exponential

reproductive investment

all of the material and energetic contribution that an individual will make to its offspring

Mutations that cause sickness and death after reproduction:

an be passed on to future generations.

aging

an increased risk of dying with increased after reaching the age of maturity

In the lynx-snowshoe hare oscillating cycle of population growth, when the hare population size grows, more food is provided for the lynx. Which is the IMMEDIATE next step in this cycle? a) The lynx population crashes. b) The lynx reproduce at a higher rate. c) The hare population crashes. d) The hare population grows further. e) The food source for the rabbit increases.

b) The lynx reproduce at a higher rate.

When more than two members of the same species live in the same place at the same time, they constitute: a) a biome. b) a population. c) an ecosystem. d) a community. e) a niche.

b) a population.

Life-history patterns: a) show up in the fossils of plants. b) are subject to the pressures of natural selection. c) exist only in organisms that exhibit parental care. d) are usually learned. e) have no genetic component.

b) are subject to the pressures of natural selection.

A species most likely to exhibit the Type II survivorship curve depicted above would be: a) chimpanze. b) blue jays. c) giant tortoises. d) humans. e) fruit flies.

b) blue jays.

During exponential growth, the per capita rate of increase is: a) ever-increasing. b) constant. c) leveling off. d) approaching the carrying capacity. e) approaching zero.

b) constant.

Studies of human demography have revealed that: a) countries with efficient systems of food production and distribution have low death rates. b) countries with higher levels of education and employment have low birth rates. c) post-industrialized countries have high birth rates. d) preindustrial countries usually have low birth rates. e) developing countries in the process of becoming industrialized tend to have high death rates.

b) countries with higher levels of education and employment have low birth rates.

A inverted population pyramid represents _____ while a column-like population pyramid represents _____. a) a young population; increasing growth b) declining growth; stationary growth c) increasing growth; stationary growth d) increasing growth; declining growth e) stationary growth; increasing growth

b) declining growth; stationary growth

What type of effect has an increasing impact as the population size increases? a) density-independent effect b) density-dependent effect c) K effect d) mortality effect e) survivorship effect

b) density-dependent effect

Which factor is MOST LIKELY to have a density-independent influence on population growth? a) infectious diseases b) extreme weather conditions c) crowding of a niche d) availability of essential nutrients e) availability of shelter

b) extreme weather conditions

Dr. David Reznick has studied life history evolution in guppies that live in streams in Trinidad. Guppies are found in two different types of habitat: sites where predation is high, and sites where predation is low. Which of the following life history characteristics would you expect to evolve in a guppy population living in a high-predation site? a) bright colors and courtship displays b) increased egg size c) delayed sexual maturation d) a female-biased sex ratio e) increased egg number

b) increased egg size

A population's survivorship curve is a downward-sloping straight line when: a) the birth rate exceeds the death rate. b) the mortality rate is constant regardless of age. c) the mortality rate increases with age. d) juvenile mortality is low. e) all individuals live to about the same age.

b) the mortality rate is constant regardless of age.

In general, there is a positive correlation between body size and generation time. This statement is: a) true; larger animals tend to have fewer offspring. b) true; larger animals tend to have a longer generation time. c) false; the correlation is between small body size and longer generation time. d) true; however, after reaching a certain body size, this correlation levels off. e) false; however, there is a correlation between body size and type of survivorship curve.

b) true; larger animals tend to have a longer generation time.

reproduction and growth life trade-off

beech trees grow much more slowly in the years when they produce many seeds than they do in years when they produce few seeds

reproduction and offspring life trade-off

big-bang reproducers such as salmon make a single, exceptionally high investment in reproduction and then die shortly afterward

In 1900, the world had a human population of approximately _______________, and, in 2000, the world had a human population of approximately _______________. a) 2.8 billion; 4.4 billion b) 4.3 billion; 6.7 billion c) 1.6 billion; 6.1 billion d) 2.5 billion; 5.2 billion e) 550 million; 7.4 billion

c) 1.6 billion; 6.1 billion

Approximately what was the human population of the world in the year 1950? a) 1.6 billion b) 4.8 billion c) 2.5 billion d) 850 million e) 650 million

c) 2.5 billion

Which of the following is NOT true about a population? a) Birth and death rates are features of a population. b) A population contains a group of individuals of the same species. c) Individuals within a population undergo genetic change. d) Members of the same population can mate with each other. e) Individuals are not "endangered," but populations can be.

c) Individuals within a population undergo genetic change.

In logistic population growth, as the population size, N, approaches the environment's carrying capacity, K, what happens to the rate of population increase? a) It increases exponentially. b) It approaches K. c) It approaches 0. d) It decreases exponentially. e) It remains less than K.

c) It approaches 0.

Which of the following statements about natural selection is TRUE? a) Natural selection operates only on people of advanced age. b) Natural selection has produced increasing numbers of people that choose never to have children. c) Natural selection "weeds out" alleles that cause death in early life. d) Natural selection has produced a high degree of infant mortality in humans, compared to other species. e) Natural selection tends to increase the risk of dying from external forces.

c) Natural selection "weeds out" alleles that cause death in early life.

There is a tradeoff between the number of offspring an organism can produce and the amount of care the organism can provide for its offspring. This statement is: a) incorrect; tradeoffs exist between the number of offspring and their size. b) incorrect; the tradeoff exists between the size of the offspring and the amount of care the parent can provide. c) correct; this is one of the inherent tradeoffs in life history strategies. d) incorrect; tradeoffs exist between the number of offspring and the size of the offspring an organism can have. e) correct; this is referred to as the "cost of reproduction."

c) correct; this is one of the inherent tradeoffs in life history strategies.

A population pyramid: a) directly predicts future age distributions of the population. b) shows the current birth and death rates of a population. c) reflects the number of individuals in various age groups in a population. d) predicts survival and mortality rates for an individual at a given age. e) All of the above.

c) reflects the number of individuals in various age groups in a population.

In years when beech trees produced a large crop of nuts, growth rings were narrow. This is best explained by: a) the climate was not condusive to growth. b) the type 1 life history of beech trees. c) the tradeoff that exists between growth and reproduction. d) the tradeoff between the number and size of offspring an organism can produce. e) density-dependent factors

c) the tradeoff that exists between growth and reproduction.

A primary difference in the age-pyramids of industrialized versus third-world countries is that: a) in third-world countries the few that survive childhood live to a very old age. b) third-world countries show a characteristic "bulge" that indicates a baby boom. c) third-world countries have much larger proportions of their population in the youngest age group. d) mean longevity is significantly greater among third-world countries. e) third world countries have significantly more individuals than industrialized countries.

c) third-world countries have much larger proportions of their population in the youngest age group.

density-independent limitation factors

can knock a population down, acting like "bad luck" limits to population growth -includes: -fires, floods, earthquakes

The population size that a particular habitat can support indefinitely is called the:

carrying capacity

The population size that a particular habitat can support indefinitely is called the: a) fundamental niche. b) intrinsic population size. c) realized niche. d) community. e) carrying capacity.

carrying capacity

carrying capacity, K

ceiling on growth for population

population density

the number of individuals in a given area

Which of the following scenarios is MOST likely to result in oscillations of two populations together? a) One population forms giant swarms that attack the other population. b) Both populations form giant swarms that cause simultaneous decreases in population size. c) Mob behavior causes a reduction in reproductive capacity. d) One population is the sole predator of another population. e) One population forces another to commit suicide.

d) One population is the sole predator of another population.

Which of the following is TRUE about estimating human carrying capacity? a) Quality of life is rarely a factor used in determining the carrying capacity. b) Technological innovations usually decrease carrying capacity. c) The United States is a model country when it comes to sustainable living. d) Some countries have more resources than their populations can currently use. e) Humans are currently living in all potential habitats offered on Earth.

d) Some countries have more resources than their populations can currently use.

The death rate of organisms in a population exhibiting a Type III survivorship curve is: a) unrelated to age. b) more or less constant throughout their lives. c) higher in post-reproductive than in pre-reproductive years. d) lower after the organisms survive beyond the earliest age groups. e) usually correlated with density-independent causes.

d) lower after the organisms survive beyond the earliest age groups.

A population's survivorship curve is a downward-sloping straight line when: a) all individuals live to about the same age. b) the mortality rate increases with age. c) the birth rate exceeds the death rate. d) the mortality rate is constant regardless of age. e) juvenile mortality is low.

d) the mortality rate is constant regardless of age.

"Ecology" is best defined as: a) the study of plant succession. b) the study of the relationships between parasites and their hosts. c) the study of the tortoise and the hare. d) the study of the relationships between all living organisms and their environments. e) the study of interactions between predator and prey populations.

d) the study of the relationships between all living organisms and their environments.

Which of the following is NOT an example of a density-dependent limiting factor that will influence carrying capacity? a) disease b) territory availability c) predation d) water quality e) food supply

d) water quality

reproductive output

the number of offspring you produce

Which of the following is NOT a mechanism by which humans have so far avoided growth beyond their carrying capacity? a) the ability to produce more food with that previously possible b) the ability to expand into new habitats c) the ability to cure previously fatal diseases d) the ability to live in higher densities than before e) All of the above are mechanisms by which humans have avoided reaching their carrying capacity.

e) All of the above are mechanisms by which humans have avoided reaching their carrying capacity.

The graph above shows the population size at which a population can most effectively be utilized for natural resources. Why does the light green line on the graph become flat after initially increasing? a) When a population's maximum sustainable yield is reached, it is growing at its slowest rate. b) When a population reaches the carrying capacity, organisms die at a faster rate. c) As a population gets closer to the carrying capacity of its environment, its growth increases steadily. d) As a population nears its maximum sustainable yield, growth is impaired. e) As a population gets closer to the carrying capacity of its environment, its growth slows and plateaus at that point.

e) As a population gets closer to the carrying capacity of its environment, its growth slows and plateaus at that point.

What may happen when a population exceeds its carrying capacity? a) The population will slowly decline until it reaches its carrying capacity and fluctuate about that number. b) The carrying capacity is not important but the population pyramid increases. c) The level of resources in the habitat will increase equally. d) The population may shoot past its carrying capacity too quickly and then crash. e) Both a) and d) are possible.

e) Both a) and d) are possible.

Which of the following shows the correct order of ecological levels, from lowest to highest in complexity? a) individuals > populations > ecosystems > communities b) ecosystems > communities > individuals > communities c) communities > populations > ecosystems > individuals d) populations > communities > individuals > ecosystems e) None of the above correctly shows the order from lowest to highest.

e) None of the above correctly shows the order from lowest to highest.

Exponential growth can continue indefinitely only if: a) the carrying capacity of the habitat (K) is very high. b) the population starts out very small. c) the population starts out high but grows slowly. d) the carrying capacity of the habitat (K)is a moderate figure. e) None of the above is correct; exponential growth cannot continue indefinitely.

e) None of the above is correct; exponential growth cannot continue indefinitely.

A key factor in determining the longevity of an organism is: a) its age at reproduction. b) the hazards that an organism is subjected to on a daily basis. c) its eating habits. d) All of the above are correct. e) Only a) and b) are correct.

e) Only a) and b) are correct.

Studies of human demography have revealed that: a) post-industrialized countries have high birth rates. b) preindustrial countries usually have low birth rates. c) countries with efficient systems of food production and distribution have low death rates. d) developing countries in the process of becoming industrialized tend to have high death rates. e) countries with higher levels of education and employment have low birth rates.

e) countries with higher levels of education and employment have low birth rates.

In a population, as N approaches K, the logistic growth equation predicts that: a) the population size will be close to doubling in size. b) the population will become monophyletic. c) the growth rate will not change. d) the carrying capacity of the environment will increase. e) the growth rate will approach zero.

e) the growth rate will approach zero.

age pyramids show the number of individuals in a population within any age group and they allow us to

estimate birth and death rates over multi-year periods

life history trade-offs

reproduction and survival reproduction and growth number and size of offspring

hazard factor

risk of dying

Type II

survivorship decreases at a steady, regular pace

life table

tallies the number of people in a population within a certain age group and the number of individuals within that age range who die

growth rate

the change in the number of individuals in the population in some unit of time, usually years rXN r= birth -death rate N= # of individuals in population now

life history

the species' vital statistics, including age at first reproduction, probability of survival and reproduction at each age, litter size and frequency, and longevity

ecology

the study of interactions between organisms and their environments.

A primary difference in the age-pyramids of industrialized versus third-world countries is that:

third-world countries have much larger proportions of their population in the youngest age group.

if a population is not growing

ultimately each individual that dies will be replaced by a new individual

most ecological processes cannot be observed or studied within an individual but rather

we need to consider the entire group of individuals that regularly exchange genes in a particular locale