Population Regulation Flashcards
(21 cards)
What is exponential growth?
A growth pattern where the population increases rapidly over time without any limiting factors
Exponential growth is characterized by a constant rate of increase, leading to a J-shaped curve when graphed.
Define density dependence.
Population growth is regulated by the population density, where growth rates decrease as population density increases
This can lead to increased competition for resources.
What is logistic growth?
A growth model that describes how populations grow more slowly as they approach their carrying capacity (K)
Equation: dN/dt = rN(K-N)/K.
What does K represent in population dynamics?
Carrying capacity, the maximum sustainable population size for the prevailing environment
K is influenced by available resources and environmental conditions.
What is the significance of Thomas Malthus’s theory?
He warned that human reproduction would outpace food production, leading to famine
Malthus’s ideas remain relevant in discussions about population growth and resource limits.
What has been the trend in global population growth rates since the 1970s?
The growth rate has slowed from 2.1% (1965-1970) to 1.1% currently
This reflects various factors, including increased access to education and family planning.
Fill in the blank: Intraspecific competition occurs when _______.
resources are limited
What is self-thinning?
A progressive decline in density of plants or animals associated with the increasing size of individuals
This phenomenon often occurs in crowded populations as resources become limited.
True or False: Competition can reduce reproductive rates.
True
What role does social behavior play in population regulation?
It helps manage resource use and can influence population density
Social structures can enhance survival and reproductive success in group-living species.
Define the Allee effect.
Population growth rate increases with density, particularly in species that have difficulty finding mates at low densities
The Allee effect can lead to extinction risks in small populations.
What is the Minimum Viable Population (MVP)?
The smallest isolated population having a 99% chance of remaining extant for 1000 years
Populations < 1000 are highly vulnerable (vertebrates); much higher for invertebrates/plants (~10,000)
What does Population Viability Analysis (PVA) assess?
It quantifies extinction risk using species characteristics and environmental variability
PVA involves stochastic projections to estimate the likelihood of population persistence.
What is the Minimum Dynamic Area?
The area of suitable habitat needed to support the Minimum Viable Population
This area can be significant, especially for large carnivores requiring extensive territories.
True or False: Humans have not impacted natural population regulation mechanisms.
False
What can happen when population regulation goes awry due to human activity?
Resource over-abundance, dependence, and management controversies can arise
Examples include the overpopulation of species like moose and Canada geese in certain areas.
What are some limiting factors for human population growth according to E.O. Wilson?
Nitrogen, phosphorous, and carbon
These factors can constrain the maximum sustainable population size.
What is the relationship between density dependence and fecundity?
In density dependent populations, increased competition can lower fecundity and growth rates
This is crucial for understanding population dynamics and conservation efforts.
Assumptions made when it comes to population regulation?
*Unlimited resources
*Constant environment
Define the Anthropogentic Allee Effect
A theory that explains how high demand for rare species can lead to extinction.
The AAE is based on the idea that the price of a species increases as it becomes rarer, which encourages more harvesting.
This cycle can drive a species to extinction
Examples of Anthropogentic Allee Effect
- Collections
- Trophy hunting
- Luxury items
- Exotic pets
- Ecotourism
