Population Dynamics Flashcards
(18 cards)
What is culling?
Culling is the process of artificially controlling a population, often through the removal of individuals, to enable the species or habitats to survive where natural control mechanisms no longer regulate the population.
Culling may be necessary when predator populations decline or when human activities disrupt ecological balances.
What were the deer predators in the Kaibab region?
The primary predators of the deer included mountain lions and wolves.
The removal of these predators led to an overpopulation of deer.
What caused the sudden decline in the deer population after 1924?
The decline was primarily due to the removal of natural predators and subsequent overpopulation, leading to food shortages and disease.
This situation illustrates the impacts of predator removal on prey populations.
What is the carrying capacity of an area?
The carrying capacity is the maximum population that a habitat can support sustainably.
It can change due to environmental factors, such as resource availability and habitat conditions.
What factors affect mortality rates in populations?
Factors affecting mortality rates include:
* Drought
* Flood
* Disease
* Volcanic eruptions
* Environmental resistance
Environmental resistance encompasses all factors that may limit population growth.
Define density-dependent factors.
Density-dependent factors are factors whose effects on populations depend on the density or size of the population, such as food supply, predation, and disease.
As population density increases, these factors become more significant.
Define density-independent factors.
Density-independent factors are factors whose effects on populations do not depend on the density or size of the population, such as chemical pollution, temperature, drought, and hurricanes.
These factors can affect all individuals in a population regardless of size.
What is migration in the context of wildlife?
Migration refers to the regular cyclical movement of entire populations to and from areas, usually to find the best areas for feeding or breeding.
Most wildlife migrations follow the annual cycle of seasons.
What is the difference between r-selected and k-selected species?
r-selected species:
* Rapid reproduction
* Early sexual maturity
* High offspring numbers
k-selected species:
* Slow recovery from population declines
* Late sexual maturity
* Few offspring
r-selected species include mice, while k-selected species include whales and elephants.
What does reproductive potential mean?
Reproductive potential is the maximum possible rate of reproduction of a species under optimum conditions and unlimited resources.
It ensures sufficient offspring to replace dying individuals.
What determines population growth?
Population growth is determined by:
* Birth rate
* Mortality rate
* Immigration
* Emigration
The equation for population change is: (births + immigration) - (mortality + emigration).
What are the stages of population growth?
The stages are:
* Colonisation
* Lag Phase
* Log Phase
* Stabilising Phase
* Stable Fluctuating Phase
Each stage represents different dynamics of population establishment and growth.
What is homeostasis in population dynamics?
Homeostasis refers to the combined processes that maintain balance in a living organism or the environment, including population control mechanisms.
Negative feedback processes help return a system to equilibrium.
What is environmental resistance?
Environmental resistance includes all factors that limit the growth of a population, such as resource scarcity and adverse climatic conditions.
It directly impacts mortality rates and population stability.
What is the significance of predator-prey relationships in population dynamics?
Predator-prey relationships illustrate self-regulation of population sizes, where predator populations typically follow the trends of prey populations with a time lag.
This dynamic can lead to oscillations in population numbers.
What is a J-shaped growth curve?
A J-shaped growth curve describes a situation where population growth stops abruptly due to environmental resistance, which is independent of population density.
This can occur due to factors like seasonality or resource depletion.
What is the impact of carrying capacity on population size?
If the population is below carrying capacity, survival is good and the population rises. If above, survival is challenging, leading to population decline.
Carrying capacity can fluctuate based on environmental changes.
What management practices can increase carrying capacity?
Management practices include:
* Providing water
* Preventing flooding
* Controlling food supply
* Managing breeding sites
* Controlling disease
* Predator and competitor control
These practices aim to enhance habitat conditions for desired species.
