Population Growth and Resource Availability Flashcards
(29 cards)
what limits population growth?
population growth is limited by environmental factors, especially by the available resources and space
can resource availability and the total resource base be depleted?
yes, resource availability and the total resource base are limited and finite over all scales of time
when does population growth accelerate?
when the resources needed by a population for growth are abundant
what happens when the resources needed by a population for growth are abundant?
population growth usually accelerates
what happens when the resource base of a population shrinks?
the increased potential for unequal distribution of resources will ultimately result in increased mortality, decreased fecundity, or both, resulting in population growth declining to, or below, carrying capacity
what is fecundity?
the ability to produce an abundance of offspring or new growth; fertility
what are the population characteristics?
size, density, distribution, sex ratio, density-dependent growth factors, density-independent growth factors
what is population size?
the total number of individuals in a given area at a time
what does a larger population size protect against?
a larger population is safer from population decline
what is population density?
the number of individual per unit of area
what is an example of population density?
12 panthers/km^2
what are the risks of a high population density?
higher competition, higher possibility for disease outbreak, higher possibility of depleting food source
what is population distribution?
how individuals in a population are spaced out compared to each other
what are the three types of population distribution?
random (trees)
uniform (territorial animals)
clumped (herd/group animals)
what is sex ratio in a population?
the ratio of males to females
what is the ideal sex ratio? why?
the closer the sex ratio is to 50:50, usually the more ideal for breeding
what are some causes of a skewed sex ratio?
die-off or a bottleneck event
what is the effect of a skewed sex ratio?
having not enough females in a population limits population growth
what are density-dependent growth factors?
factors that influence population growth based on the size of the population
what are density-independent growth factors?
factors that influence population growth independent of the size of the population
what are some examples of density-dependent factors? why are they density-dependent?
disease, competition for food, habitat, water, light
all of these things limit population growth based on their size (a small population doesn’t experience these things, but a large population does)
what are some examples of density-independent factors? why are the density-independent?
natural disasters (flood, hurricane, tornado, fire)
it doesn’t matter how big or small a population is, natural disasters limit them both
what is an example of food being a density dependent factor?
if twice as much food is added to a dish of two species of bacteria, both species’ carrying capacity increased by twice the amount
(food is also a limiting resource)
what is biotic potential?
maximum potential growth rate, with no limiting resources
