Final answer:
The primary reproductive trait associated with terrestrial environments is internal fertilization, an adaptation that protects gametes in non-aquatic settings. Terrestrial animals also exhibit diverse mating behaviors and territory defense mechanisms critical for reproductive success. Environmental factors can influence reproductive traits, as seen with temperature-dependent sex determination in certain reptiles.
Step-by-step explanation:
The reproductive trait commonly associated with terrestrial environments is internal fertilization. This adaptation is crucial as it protects the gametes from desiccation; a significant risk associated with non-aquatic environments.
Internal fertilization is seen across various land animals and facilitates successful mating and the subsequent development of offspring in these dryer and potentially more variable climates. Additionally, terrestrial animals showcase diverse mating behaviors and territory defending, which are important strategies for attracting mates and ensuring reproductive success.
Animals that can secure and defend a territory are more likely to attract a mate and therefore have higher fitness. The distribution and density of individuals within a population can influence mating success, with territorial species often having a more predictable pattern of distribution. Furthermore, specific conditions of the terrestrial environment, such as temperature, can even influence phenotypic traits like sex determination in some species, as with temperature-dependent sex determination (TSD) observed in certain reptiles.
Different land animals exhibit a variety of specialized reproductive structures and strategies such as ovipary, ovovivipary, and vivipary. These strategies, alongside other reproductive adaptations, are responses to the environmental pressures of terrestrial habitats, allowing for the successful propagation of species within these ecosystems.