Chapter 5: Biodiversity, Species Interactions, and Population Control

Biotic potential

Maximum growth potential of an organism under optimal environmental conditions

Boom and bust growth cycle

when the growth of a population is closely tied to the limiting factors set in the ecosystem

Coevolution

When predator and prey evolve together due to intense natural selection

Commensalism

A symbiotic relationship in which one organism benefits and the other receives nothing

Cyclical succession

the cycle in which an environment develops (primary and secondary succession)

Degradative succession

A succession that occurs when dead organic matter over a short period of time

Density dependent

 When the density of a population is dependent on the limiting factors of an environment

Density independent

When the growth of a population is not dependent on limiting factors of an environment

Environmental resistance

factors that limit a population

Exponential population growth

When a population grows unchecked for a sustained period of time

Generalist species

A species that has a wide niche and wide range of tolerance

Interspecific competition

Competition among different species for the same resources

Intraspecific competition

Competition among the same species

Intrinsic rate of increase

Also known as the population change

• The rate of (births + immigrations) - (deaths + emigration)

Keystone species

a species that plays a critical role in sustaining the ecosystem

Logistic growth

When the population’s growth rate decreases as they reach the maximum carrying capacity

Minimum viable population

The number of individuals required to increase the probability of the survival rate of a population over a given period of time

Mutualism

A symbiotic relationship in which both organisms benefit

Natural selection

Characteristics that are favorable in an environment and are passed down while undesirable characteristics are bred out of the gene pool

Niche

A specific ecological role a species plays in an environment

Parasitism

A symbiotic relationship in which one organism harms/weakens the other

Predation

A symbiotic relationship in which one organism hunts the other for food

Primary succession

A type of succession in which the ecosystem starts from bare rock

Resource partitioning

when only specific resources are used. This allows for greater species diversity as it creates more niches

Resilience

 Ability of a living system to be restored through secondary succession after a moderate disturbance

Secondary succession

A type of succession that occurs only when soil is present (usually after a fire)

Specialist species

A species that has a narrow niche and narrow range of tolerance

Survival of the fittest

Darwin’s theory of natural selection and evolution

Symbiosis

The interaction between two different organisms that live in close physical association

r-selected species

Species that are: 

• Small

• Produce many offspring

• Invest little care in their young 

• Few survive to reproduce

K-selected species

Species that are: 

• Large 

• Produce few offspring

• Invest a lot of care in their offspring

• Most survive to reproduce

Chemical Warfare

This is the use of certain chemicals to avoid predators or catch prey

Examples of Chemical Warfare

• Snake paralyzes prey and then eats them

• Poisonous dart frog uses chemicals to avoid being eaten

Population change formula

Number of: 

(births + immigrations) - (deaths + emigrations)

How have humans increased the earth’s carrying capacity?

Through migration, agriculture, medical advances, and communication

Type I survivorship

Invest time and effort in offspring and the offspring survive long enough to reproduce

Type II survivorship

When the rate of births is equal to the rate of deaths

Type III survivorship

Invest little time and effort in their offspring and most offspring don’t survive long enough to reproduce

What happens when populations exceed K?

There will likely be a population crash that will ultimately decrease the ecosystem’s carrying capacity

What are limiting factors and how do they control population growth?

Limiting factors place restrictions on how quickly and how great a population can grow.