Download Ecology - the study of the relationships between organisms and their

Ecology - the study of the relationships between organisms and their environment. The environment includes an
organism’s its surroundings and other organisms. Ecology studies the relationships and interactions among
individuals within a population and with individuals of different populations. Because all organisms have become
adapted to their surroundings and are always adapting to a changing environment, natural selection and evolution
are also a part of ecology
Population - a population consists of the individuals of a given species that occur together at one place at one
time. The population is the major functional unit of the ecosystem and it plays a particular role in energy flow and
cycling of nutrients
Ecosystem - an ecosystem is the sum of all of the biological and nonbiological parts of an area that interact to
cause plants to grow and decay, soils or sediments to form, and the chemistry of water to change
rmax = maximum intrinsic rate of natural increase for a population
Biotic potential - the innate capacity of a population to increase in number under ideal conditions = rmaxN
r = the actual rate of population increase = dN/Ndt = (b - d)/N
Environmental resistance - a natural check on the growth of wild populations; includes factors such as disease,
accumulation of waste products, lack of food, lack of space, light, or water
Carrying capacity = K = the number of individuals in a population that can be supported at a given place over a
long period of time
logistic growth equation = dN/dt = rmax N((K - N)/K)
SOME CHARACTERISTICS OF r AND K STRATEGISTS
r strategists
K strategists
Climate
variable and/or unpredictable
fairly constant and/or predictable
Mortality
density independent
density dependent
Survivorship
high mortality when young; high
survivorship afterwards
either little morality until a certain
age, or constant death rates over a
period of time
Intraspecific and interspecific
competition
variable, lax
usually keen
Parental care
minimal
intensive
Adaptations
rapid development; high rate of
population increase; early
reproduction; small body size;
single reproduction (big bang =
semelparity)
slower development; greater
competitive ability; delayed
reproduction; larger body size;
repeated reproductions
(iteroparity)
Length of life
Usually less than one year
Usually more that one year