AIPMT-NEET Aspirants, read out the next AIPMT-NEET Biology Study material/ Notes of r-selected and k-selected species, important for AIPMT-NEET Biology. Free online notes for AIPMT-NEET.
Life history adaptations depend on availability of resources. Species vary in their capacity to reproduce due to adaptation to different habitat conditions. r-selected species use wide variety of resources and tolerate wide range of conditions while k-selected species are adapted to predictable environment, use resources in specialized way and are less tolerant to variations.
These are also called as life history strategies, i.e. r-strategies and k-strategies.
r-selected species achieve the maximum possible rate of population increase in favorable environment while k-selected species population increase is checked by carrying capacity (K) of the environment.
NOTE: Carrying capacity is the maximum number of individuals in a population that can be supported by resources present in that environment.
Following is the table indicating the difference between r-selected species and k-selected species.
|Division on the basis of||r-selected species||k-selected species|
|Mating type||Random mating||Mate choice|
|Number of reproductions in life||Reproduce once (called as Semelparity)||Reproduce many times (called as Iteroparity)|
|Number of offspring produced per reproduction||Many||Few|
|Parental care||No parental care||Extensive care|
|Size of offspring/eggs||Small||Large|
|Habitat||Broad range of habitat||Specific habitat|
|Example||House flies, cockroaches, mice, dandelions etc.||Coconut palms, whales, human, oak trees etc.|