Responses to Environment
A change in an organism’s environment that causes a response.
stimulus
An organism that makes its own food using sunlight or chemical energy.
producer
The maximum number of individuals an environment can sustainably support.
carrying capacity
A factor whose effect increases as population density increases (e.g., disease).
density-dependent
A symbiotic relationship where both species benefit.
mutualism
A plant movement in response to light, growing toward the light source.
phototropism
A complex network of feeding interactions in an ecosystem.
food web
A J-shaped curve representing rapid population increase with no limits.
exponential growth
When organisms fight for limited resources like food or space.
competition
Species use different resources or habitats to reduce competition.
niche partitioning
A behavior that is genetically programmed and not learned
innate behavior
The total amount of energy captured by producers in an ecosystem.
GPP
An S-shaped curve showing population growth that levels off at carrying capacity.
logistic growth
A resource or condition that limits the growth, abundance, or distribution of a population.
limiting factor
A species that has a disproportionately large impact on its ecosystem.
keystone species
A random movement that increases or decreases with stimulus intensity.
kinesis
The rule stating only ~10% of energy is passed from one trophic level to the next.
10% rule
An organism that reproduces quickly and in large numbers; short life span.
r-strategist
A relationship where one organism hunts and eats another.
predation
The natural, gradual changes in species that occur in a community over time.
succession
A form of learning where an animal forms a strong attachment during a critical period.
imprinting
The energy available to consumers after producers use some for respiration.
net productivity
A graph showing the percentage of survivors over time in a population.
survivorship curve
Factors like natural disasters that affect populations regardless of density.
density-independent
The number of different species in a community.
species richness