What are opportunistic or r-selected species?

R-selected or opportunistic species are species that have high growth rates, produce many offspring, and have low survival odds for those many offspring. These species typically have little parental care and reproduce often.

Examples include bacteria, many plants, and most insects.

R-selected species can be contrasted with k-selected species which have slower growth rates, produce few offspring with increased parental care and higher survival odds, and that reproduce at longer intervals.

Examples of k-selected species include mammals such as humans, dolphins, and rhinos.