R-selected species (or opportunist species) is a term to describe a particular reproductive and survival strategy for organisms. R-selected species get their name because of their signature high intrinsic rate of population growth (r). These species are usually small in size and have short life spans. Because of this lifestyle, there is increased pressure to propagate, so r-selected species usually reach reproductive age early in life and have many offspring each time they reproduce. After conception, the parent does not protect or care for its offspring so many eventually die, but few will survive and begin the cycle again. r-selected species are opportunists, meaning they take advantage of favorable conditions to reproduce, especially when there is a disturbance that opens up a new habitat or niche for invasion.

Examples of r-selected species:

1. algae
2. bacteria
3. rodents
4. annual plants, like dandelions
5. most insects, like cockroaches

See also

• K-selected