Question

What type of organisms are considered r-selected?

Answer 1

Species that thrive in disturbed habitats, such as freshly burned grasslands or forests, are called r-selected species. These species respond opportunistically. They are the first ones to thrive in a newly destroyed environment.

Complete answer:
R-selected species are also called r-strategist species. The growth curve of their population is governed by a connotation called “biotic potential”. The terms refer to the maximum reproductive capacity of an organism under optimum environmental conditions. The characteristics features of the r-selected species is that they have short gestation periods and life spans. Their offspring often don’t end up alive due to adverse conditions. Therefore, their biotic potential is very high. The harmonious habitation of r-selected species in a particular environment is often temporary as other more competitive species take over eventually or overcrowding sets in.
ΔN÷Δt = rN is the equation which follows the exponential growth of the r-selected species (where, N is the number of individuals in the population and t is the time). An example of r-selection strategy is mice and its litter since they exhibit short gestation, more number of offsprings, less parental care and a short time until sexual maturity. These organisms range from bacteria and diatoms, to insects and grasses, to semelparous cephalopods and small mammals, especially rodents.

Note:
R-selection strategy is one of the two selection strategies proposed by American ecologist Robert MacArthur and American biologist Edward O. Wilson. The other strategy being the K-selection strategy. In the above mentioned equation, the factor (1-[N\K]) can also be added to indicate an upper limit on population growth.