Final answer:
K-selected species are adapted to stable environments, produce fewer, larger offspring, and provide significant parental care. Examples include elephants and oak trees. The K- and r-selection theory has been revised but still influences understanding of species' life histories.
Step-by-step explanation:
Definitions and Characteristics of K-selected Species
K-selected species are those that thrive in stable and predictable environments, often remaining close to the carrying capacity of their habitat. These species experience high levels of intraspecific competition and typically have fewer, larger offspring. They also tend to give extensive parental care, have long gestation periods, and their offspring are relatively helpless at birth, requiring time to acquire the necessary skills to survive and compete for resources. Parental care in plants is demonstrated by the time it takes for fruit to develop and how long it remains on the plant. Notable examples of K-selected species include elephants, primates (including humans), and certain types of plants such as oak trees.
K-selected species contrast with r-selected species, the latter being adapted to unstable environments, having many small offspring, and providing little to no parental care. The strategies of both K-selected and r-selected species exist on a continuum, and some species may exhibit traits that align towards one end or the other.
Despite the historical use of K- and r-selection theory in explaining life history evolution, recent studies have led to modifications and a shift towards more demographically-based models that incorporate broader ecological concepts, such as population age structure and mortality factors. Nonetheless, many of the core ideas of K-selection theory are still relevant for understanding population dynamics and species' reproductive strategies.