Chapter 20 Flashcards
Population
a group of individuals of the same species, in the same area, at the same time
studying individuals in population can provide info on:
life span, food preferences, reproductive cycle
Community
- Made up the populations of all organisms that occupy an area
- study how different populations interact with one another (competition, predation, parasitism, mutualism, etc.)
Ecosystem
Includes community (biotic factors) and surrounding abiotic factors
intraspecific competition
how individual members of one species interact with each other
interspecific competition
can describe how population interacts with each other
Geographic Range
region where a given organism is sighted
Habitat
- the physical area where a species lives
- usually determine by the environmental conditions under which the population has the best chance of survival
- habitat is limited by factors such as climate, soil conditions, vegetation, etc.
Ecological Niche
the overall role of a species in its environment
A statement of the size of a population must include:
the number of organisms, the location, the time when numbers were determines
Natality
number of offspring of a species born in one year
Mortality
number of offspring of species that die in one year
immigration
number of individuals of species moving into existing population
emmigration
number of individuals of species leaving existing population
Dynamic Equillibrium
in mature ecosystems, populations tend to remain stable and adjust to changes in their environment - balance is known as dynamic equillibrium
Open population
one is which density changes as a result from the interaction of natality, mortality, immigration and emmigration
Closed Population
one in which density changes as a result from just natality and mortality with neither food or wastes being allowed to enter of leave the given environment
population explosion
population that grows so rapidly before it can be contained
population crash
population that declines so rapidly
Biotic Potential
the highest possible per capita growth rate for a population (given unlimited resources and ideal living conditions)
Factors that determine a species’ biotic potentia; include
- number of offspring per reproductive cycle
- the number of offspring that survive long enough to reproduce
- the age of reproductive maturity and the number of times the individuals reproduce in life span
- the life span of the individuals
organisms that have high biotic potention
small animals, microorganisms, certain plants
organisms that grow their biotic potential demonstrate:
exponential growth (J shape)
Lag Phase
In the beginning, growth of small population is slow (since only a few reproduce)
Growth Phase
as numbers in population increase, population will experience exponential rate of growth,
(birth > death)
Stationary Phase
birth rate = death rate
S shaped curve
logistic growth pattern
Carrying Capacity (K)
the theoretical maximum population size that the environment can sustain over an extended period of time. same as the number of individuals in population that can live in a given environment without depleting resources they need or harming their habitat or themselves
factors that limit a habitat’s carrying capacity
- Density dependent factors (biotic)
- Density independent factors (abiotic)
Environmental resistance
-combination of all limiting factors
-prevents population from growing at its biotic potential
-determines carrying capacity of a habitat
In unstable environments…
it may be favourable to reproduce quickly when conditions are favourable
In stable environments..
it may be favourable to reproduce slowly
r- selected life strategies
organisms that reproduce close to their biotic potential
K- selected life strategies
populations that live close to their carrying capacity of their habitats
r selected life strategy characterisitcs
- small size
- short life span
- early reproductive age
- produce large broods of offspring that receive little to no parental care
- take advantage of favourable conditions such as availability of food, sunlight, and warm temps
K selected life strategies characteristics
- typically large size
- long life span
- later reproductive age
- produce few offspring per reproductive cycle. offspring require parental care
