chapter 7-8 Flashcards
Interspecies competition
plays a larger role in most ecosystems and intraspecies competition. When competing, niches overlap, and resources are limited. The greater the niche overlap, the more competition.
Resource partitioning
is an evolutionary adaptation that occurs competitors develop specialized traits that allow them to share scarce resources. This can involve using different parts of the resource, or using the resource at different times or in different ways. “Sharing the wealth.
Herbivores
eat plants
Omnivores
eat plants and animals
Carnivores
eat animals
Predation
is the process by which
one organism, the predator,
captures and feeds upon another
organism, the prey.
Competition
occurs when two
organisms compete for the same
limited resource. This may be
food, shelter, water, space, or any
other biotic or abiotic factor that
both organisms need to survive.
Symbiosis
is a close relationship
between organisms of different
species that live in direct contact
with one another.
Population density
is the
number of individuals living
in a defined space.
High
population density
means a
large number of individuals
living in a small area
Population Growth Rate
is the amount of individuals added to a population over time.
The Mark-Recapture technique
allows scientists to measure population of a species.
Biologists capture individuals in a population and tag them before releasing them back
into their environment. After some time, individuals are counted again, including the
previously marked organisms.
Growth Rate
or change in growth over time, is equal to the difference between the sum of the birth rate
and the immigration rate, and the sum of the death rate and the emigration rate.
Exponential Growth
population size increases dramatically over a relatively short period of
time. Growth starts slow, but increases very rapidly. This occurs when
resources are plentiful.
Logistic Growth
population size increases slowly at the start, then grows exponentially, then
levels off to a stable size. This occurs when resources are limited.
carrying
capacity
is the
maximum
population size
of a species that
an environment
can normally
and consistently
support.
limiting factor.
A factor that keeps the population size down is called a
Density-Dependent Limiting Factors
affected by the number of individuals in an area. The
larger the population, the greater the effect.
Density-Independent Limiting Factors
factors that can impact a population regardless of its
density.
type 1/k-selected
is late loss, meaning
mortality increases later in life.
type 2
is constant loss, meaning
mortality is the same death rate
throughout life.
type 3/r-selected
is early loss,
meaning mortality is high at an
early age.
Resilience
is the ability of an ecosystem to recover after it
has undergone a disturbance. For example, a grassland
that has regular fires is considered resilient, because the
grasses quickly regrow and the animals return very soon
after a fire ends.
Genetic diversity
allows different traits to be available in
a species. High genetic diversity in a species increases the
population’s chance of adapting to disturbances.
Resistance
is the ability of an ecosystem to resist change
due to disturbances. Highly resistant ecosystems remain
essentially unchanged when a disturbance occurs.
Ecological succession
is the sequence of biotic changes that restore a damaged community or create a
community in a previously uninhabited area.
Primary Succession
is the establishment and
development of an ecosystem in an area that
was previously uninhabited, usually a bare rock
surface. This process takes hundreds of years.
Secondary succession
is the reestablishment of an ecosystem in an area where the soil was left intact,
such as after a fire or flood. This process is much faster than primary succession. Pioneer species like
lichen are not required to start the growing process. Plants can start growing in the soil that is already
present. Although faster overall, the stages of plant growth are similar.
Cultural Carrying Capacity
the maximum number of people who
could live in reasonable freedom and comfort indefinitely, without
decreasing the ability of the earth to sustain future generations.
Environmental Worldview:
the assumptions and beliefs that you have about how the natural
world works and how you think you should interact with the environment.
Environmental Ethics
what you believe about what is right and what is wrong in your
behavior toward the environment
Total fertility rate (TFR)
The average number of children
born to the women of childbearing
age in a population.
Replacement-level fertility rate
The average number of children that
couples in a population must bear to
replace themselves.
2.1
immigrate
into
emigrate
out
Environmental refugees
are
people who have to leave their
homes and sometimes their
countries because of water or
food shortages, soil erosion, or
some other form of
environmental degradation.
Demographic Transition
As countries become industrialized and economically developed,
their per capita incomes rise, poverty declines, and their
populations tend to grow more slowly.
