Smith Biology Section 14.3 - 14.5

The mussels will not be found one meter apart because population density describes how many organisms are in a specific area, not the dispersion pattern.

A shoreline mussel species has a population density of one organism per square meter. Will all mussels be found one meter apart? Explain.

The organism is most likely a bird because it has a Type II survivorship curve.

An organism has ten offspring. Two of these offspring die each year over a five-year period. Is the organism more likely to be a bird or an insect? Explain.

The point before the soil formation provides the fewest habitats for organisms because it is a foundation for every ecosystem.

At what point during primary succession does an ecosystem provide the fewest habitats for organisms? Explain your reasoning. ​

Primary succession takes longer in arctic areas because rocks are covered with snow part of the year, the growing season is shorter, and cold temperatures slow down growth and decomposition.

Does the process of primary succession take longer in tropical or arctic areas? Explain.

In clumped dispersion, individuals live close together in groups. In uniform dispersion, each organism is a specific amount of length away from each other. In random dispersion, individuals are spread randomly within an area.

Draw and label a diagram showing the three population dispersion patterns.

logistic growth

During __________ _________, a population begins with a period of slow growth followed by a brief period of exponential growth before leveling off at a stable size.

The taller plants would block the sun and the mosses would receive less light and not grow as well.

During succession, what might become the limiting factor for sun-loving mosses as taller plants begin to grow?

If a disease or parasite was to spread in a population that was dense, the population could crash.

Give an example of how a symbiotic relationship could cause a population crash.

A survivorship curve is a generalized diagram showing the number of surviving members over time from a measured set of births. In Type I, there is a low infant mortality rate and a population surviving to an old age, meaning that parents take care of their young until they can survive on their own. In Type II, the survivorship rate is often equal at all ages of an organism's life. At all times, these organisms have equal chances of living and dying. In Type III, there is a very high birth rate and a very high infant mortality rate. These individuals are often targets of predation at an early age, but inevitably a few survive and reproduce.

How do survivorship curves show three types of reproductive strategies?​

Carrying capacity limits the size of a population.

How does carrying capacity affect the size of a population?

Primary succession is the establishment and development of an ecosystem in an area that was previously uninhabited. Secondary succession is the reestablishment of a damaged ecosystem in an area where the soil was left intact.

How is primary succession different from secondary succession?

Natural disasters can wipe out predators or competition.

How might density-dependent limiting factors be affected by a flood or some other natural disaster?

Heat and limited water resources may lead to high population density and clumped dispersion patterns on the African savannah.

On the African savanna, what types of abiotic factors may lead to high population density and clumped dispersion patterns?

carrying capacity

The __________ ____________of an environment is the maximum number of individuals of a particular species that the environment can normally and consistently support

limiting factor

The factor that has the greatest effect in keeping down the size of a population

Succession

The sequence of biotic changes that regenerate a damaged community or create a community in a previously uninhabited area.

Immigration, births, emigration, and deaths determine the growth rate of a population.

What four factors determine the growth rate of a population?

Density-dependent limiting factors are limiting factors that are AFFECTED by the number of individuals in a given area (ex. competition, predation, parasitism, disease). Density-independent limiting factors are the aspects of the environment that limit a population's growth REGARDLESS of the density of the population (ex. unusual weather, natural disasters, human activities).

What is the main difference between a density-dependent limiting factor density-independent and a limiting factor? Give examples of each.

Individuals may live close together in groups in order to facilitate mating, gain protection (against predation), or access food resources.

What might be the advantages of having a clumped dispersal pattern?

Eventually, the growing population will consume all available resources, and the species may experience a population crash.

What might cause exponential growth to occur only for a short period when a new species is introduced to a resource-filled environment?

exponential growth

When resources are abundant, a population has the opportunity to grow rapidly. This type of growth, called ______________________ ___________, occurs when a population size increases dramatically over a period of time.

They are the first organisms to live in a previously uninhabited area, and their presence thus increases the diversity in the area.

Why are pioneer species so important for primary succession?

survivorship curve

a generalized diagram showing the number of surviving members over time from a measured set of births

population density

a measurement of the number of individuals living in a defined space

population crash

dramatic decline in the size of a population over a short period of time

primary succession

establishment and development of an ecosystem in an area that was previously uninhabited

density-dependent limiting factors

limiting factors that are affected by the number of individuals in a given area (ex. competition, predation, parasitism, and disease)

secondary succession

reestablishment of a damaged ecosystem in an area where the soil was left intact

density-independent limiting factors

the aspects of the environment that limit a population's growth regardless of the density of the population

pioneer species

the first organisms that live in a previously uninhabited area

immigration

the movement of individuals into a population from another population

Emmigration

the movement of individuals out of a population and into another population

population dispersion

the way in which individuals of a population are spread in an area or a volume