Giant Set: Population Ecology Chapter 14 What is Life Phelan

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Jay Phelan Chapter 14 What is Life?

Ecology

The study of the ineraction between organisms and their environments.

Population Ecology

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

What are the levels of ecology?

Inidividuals, populations, communities, and ecosystems.

What is an individual?

Individual organism

What is a population?

Groups of individual organisms that interbreed with each other.

What is a community?

Populations of different species that interact with each other within a locale?

What is an ecosystem?

All living organisms, as well as non-living elements, that interact in a particular area

The important processes in population ecology include adaptations, birth rates, , death rates, immigration, and emigration. Can any of these processes be
studied at the individual level? Explain.

No because population ecology focuses on populations of organisms of a species and how they interact with the environment.

What is growth rate?

The change in the number of individuals in the population is some unit of time, such as a year.

What letter represents "growth rate?"

The letter "r"

What letter represents "number of individuals"

N

The equation to calculate the growth of a population in a year is...

r x N

What is exponential growth?

Growth of a population at a rate that is proportional to its current size.

The exponential growth is represented by what shape graph?

The J-shaped graph.

Can exponential growth occur over long periods of time?

No because a population is limited by its environment (carrying capacity).

What is population density?

The number of individuals of a population in a given area. breeding and non

What are four density-dependent factors that can impact growth?

Food supply, habitat for living and breeding, parasite and disease risk, and prediation risk.

What letter represents "carrying capacity?"

K

Name two related consequences that could occur if a population size approaches its carrying capacity (K)?

Death and emigration rates increase.

What is logistic growth?

A pattern of population growth in which initially exponential growth levels off as the environment's carrying capacity is approached.

What are two density-independent factors that can impact a population?

Weather (floods, earthquakes, fires) and habitat destruction (by other species or humans).

What growth pattern describes populations better than any other model?

The logistic growth pattern because regularly cycling populations and populations with periodic outbreaks of huge numbers are more the exception than the rule.

What is maximum sustainable yield (MSY)?

The point at which the maximum number of individuals are removed from a population without impairing its growth rate; it occurs at half the carrying capacity.

What does MSY rely upon?

It's carrying capacity.

Why is it not always easy to determine the MSY?

It is difficult to determine or estimate the carrying capacity (K) of an organism (i.e. how do we know how many lobsters live underwater).

What is life history?

The vital statistics of a species, including age at first reproduction, probabilities of survival and reproduction at each age, litter size and frequency, and longevity.

Name the four important statistics of life history?

Age at first reproduction, probabilities of survival and reproduction at each age, litter size and frequency, and longevity.

What are the two factors to consider when evaluating the costs and benefits of one reproductive strategy over another.

1) The cost of reproductive invstment during any reproductive episode (energy to produce, predatation, etc) and 2) the individuals likelihood of surviving to have future reproductive episodes (predation rates and other sources of mortality).

Describe the life history of humans?

Humans have low probability of dying so they defer reproduction and reproduce in small numbers over longer periods of time.

Describe the life history of rodents?

Rodents have high probability of dying so they produce many litters with many offspring at an early time in their lives.

What is a life table?

A table presenting data on the mortality rates within defined age ranges for a population; used to determine an individual's probability of dying during any particular year.

What is a survivorship curve?

Graphs showing the proportion of individuals of particular ages now alive in a population; indicate an individual's likelihood of surviving through a given age interval.

What information is listed on a life table?

Organism age, number of organisms alive at that age, proportion alive at that age, deaths during the interval, and probability of dying during the interval.

Name the three distinct types of survivorship curves?

Type I, Type II, and Type III

Describe Type I survivorship curve.

High survivorship until old age, then rapidly decreasing survivorship (i.e. humans and giant tortoise).

Describe Type II survivorship curve.

Surivorship descreases at a steady, regular pace (i.e. bird and squirrel).

Describe Type III survivorship curve.

High mortality early in life, but those that survive the early years live long lives (i.e. plants, insects, and fish).

An organism's fitness can impact what areas of an organism's life history?

Growth, reproduction, and survival.

Describe reproduction and survival trade-off.

Big bang reproducers require lots of energy to reproduce brings quicker death (i.e. marsupial mouse). Impeding reproduction can allow organism to live longer.

Describe reproduction and growth trade-off.

Organism grow slower when they reproduce (i.e. beech trees when producing seeds). Impeding reproduction increases growth (i.e. fremale red deer grows faster during first year of life).

Define "aging."

An increased risk of mortality with increasing age.

What is the average lifespan in the U.S.?

78 years old

What is the age of the oldest human ever documented?

122 years (Jeanne Louise Calment)

What is reproductive output?

The number of offspring an individual or population produces.

If a person is carrying a mutation that will cause disease/death at a very young age (before reproductive maturity), is it possible for them to pass the mutation on to future offspring?

No because natural selection will weed out the allele before reproduction happens so no will inherit the mutationed gene.

If a person is carrying a mutation that will cause disease or death later in life (after reproductive maturity), is it possible for them to pass the mutation on to future offspring?

Yes, because reproduction will have already occurred and the alleles have passed on their negative effects (i.e. breast cancer later in life).

What is responsible for the physical breakdown of an individual?

Mutated (or "bad") alleles.

If an organisms living in high-risk world does not reproduce quickly, what is the risk?

They will not reproduce.

What is a hazard factor?

An external force on a population that increases the risk of death.

If hazard factor is high, do organisms tend to reproduce earlier or later?

Earllier (i.e. fish)

Name an organism who experiences low hazard factor.

A human (so they reproduce later in life).

What is the "baby boom" generation?

Children born just after WWII and continuing untile the early 1960's (there was a 30% increase in the number of babies born when compared to previous and post years).

How did the "baby boom" impact society?

More schools had to be built and as these individuals approach retirement age, pension and health care expenses rise.

What is an "age pyramid?"

A visual represntation of population growth - goes from triangular to rectangular when population growth stabilitizes.

What is the shape of the age pyramid in the U.S.?

There is a noticable bulge in the pyramid for the increase of children during the baby boom years.

Define demographic transition.

A pattern of population growth characterized by the progression from high birth and death rates (slow growth) to high birth rates and low death rates (fast growth) to low birth and death rates (slow growth).

Describe the possible combinations of birth and death rates when the population growth rate is slow.

1) High birth rates and high death rates produced with 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 3) low birth rate and low death rate produced as industrialization continues, the birth rate descreases as a result of higher levels of education and employment, along with improved health care.

Describe the possible combinations of birth and death rates when the population growth is fast.

1) High birth rates and low death rates produced 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 population grows rapidly.

What is our estimated global population?

Over 7 billion people

What does the United Nations estimate our global carrying capacity as?

Between 7 and 11 billion people.

List three ways that humans, with the aid of technology, can increase our carrying capacity.

1) Expand into new habitats 2) increase agricultural productivity of the land 3) circumvent the problems that usually accompany life at higher densities (i.e. public health, waste disposal)

Define "ecological footprint."

A measure of the impact of an individual or population on the environment by calculation of the amount of resources—including land, food and water, and fuel—consumed.

Is the ecological footprint the same from country to country?

No because some countries consume more than others per person.

Community ecology

_____ is the study of how populations of different species within a location interact with each other.

ecosystem

The ways that living organisms and non-living elements interact in a particular area is the study of _____ ecology.

population

A _____ is a group of interbreeding individuals that change over time in terms of its growth rate, distribution, and genetic makeup.

growth rate

The change in the number of individuals in a population over a specific unit of time, such as a year, is called the _____.

exponential growth

The statement, "the bigger the population, the faster it grows" describes _____.

limiting factors

One or more _____ will lead to a reduction in the growth of a population.

carrying capacity

The ultimate limit on the growth of a population is the _____ of the environment.

death rate, migration rate

Name two factors that will INCREASE as a population size approaches the carrying capacity of the environment.

logistic growth

As a population's growth slows, an "S"-shaped growth curve develops. This type of growth is called _____.

dependent

Density- _____ factors include the limitations on a population's growth that are a direct consequence of the number of individuals within a given area.

independent

Density-_____ factors affect populations without regard for the size of the population.

dependent

Reduced food supplies due to competition is an example of a density-_____ factor.

dependent

An increase in parasites and infectious disease are examples of density-_____ factors.

independent

Floods, earthquakes, and fires are examples of density-_____ factors.

decrease

As a predator population increases, the prey population will _____.

maximum sustainable yield

In a carefully-managed resource, such as a fishery, as many individuals as possible are removed from the population without impairing its growth rate. This is called the _____.

life history

A _____ includes the vital statistics of a species, such as age at first reproduction and lifespan.

reproductive investment

Individuals vary in their _____, which includes the physical and energetic contribution that they will make to their offspring.

Exponential

_____ growth occurs when each individual in a population produces more than the single offspring necessary to replace itself.

logistic

Population growth that has stabilized because of limited resources will display _____ growth.

carrying capacity

Development of agricultural technologies is one example of how _____ can be increased.

True

Maximum sustainable yield is a useful concept, but difficult to put into practice because it is hard to accurately determine population size and carrying capacity in nature.

slow, gradual

An individual that produces about one offspring per year and takes one year to reach sexual maturity has a _____ reproductive investment.

fast, intensive

An individual that produces litters of 6-10 offspring every month and takes one month to reach sexual maturity has a _____ reproductive investment.

big bang

Individuals that mate intensively over a three-week period, often with the males dying shortly thereafter, have a _____ reproductive investment.

aging

For an individual is the increased risk of mortallity with increasing age, generally due to a breakdown in the body's machinery; in a population it is the increased rate of dying with increased age, characterized by multiple physiological breakdowns.

carrying capacity (K)

The ceiling on a population's growth imposed by the limitation of resources for a particular habitat over a period of time.

demographic transition

A pattern of population growth characterized by the progression from high birth and death rates (slow growth) to high birth rates and low death rates (fast growth) to low birth and death rates (slow growth).

density-dependent factors

Limitations on a population's growth that are a consequence of population density. Breeding and non

density-independent factors

Limitations on a population's growth without regard to population size, such as floods, earthquakes, fires, and lightning.

ecological footprint

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

ecology

The study of the interaction between organisms and their environments, at the level of individuals, populations, communities, and ecosystems. [Gk., oikos, home + logos, discourse]

exponential growth

Growth of a population at a rate that is proportional to its current size.

growth rate (r)

The birth rate minus the death rate; the change in the number of individuals in a population per unit of time.

hazard factor

An external force on a population that increases the risk of death.

life history

The vital statistics of a species, including age at first reproduction, probabilities of survival and reproduction at each age, litter size and frequency, and longevity.

logistic growth

A pattern of population growth in which initially exponential growth levels off as the environment's carrying capacity is approached.

maximum sustainable yield

The point at which the maximum number of individuals are removed from a population without impairing its growth rate, it occurs at half the carrying capacity.

population density

The number of individuals of a population in a given area.

population ecology

A sub-field of ecology that studies the interactions between populations of organisms of a species and their environment.

reproductive investment

Energy and material expended by an individual in the growth, feeding, and care of offspring.

reproductive output

The number of offspring an individual or population produces.

survivorship curves

Graphs showing the proportion of individuals of particular ages now alive in a population; survival curves indicate an individual's likelihood of surviving through a given age interval.

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