Question

As arthropods made the transition from water to land, they went from living in a surplus of water to the frequent pressure of preventing the negative effects of dehydration (Figure 1). While arthropods that reside in water sources with a high salt content (i.e., higher osmolarity) also experience challenges in maintaining water balance, terrestrial environments typically pose more severe challenges than aquatic ones. The terrestrialization of arthropods did not occur as a single transition; instead, multiple lineages transitioned from water to land starting at the Cambrian–Ordovician boundary (ca. 488 Ma), with direct evidence of chelicerates in the Silurian (ca. 416–443 Ma) and hexapods in the Devonian (ca. 398–416 Ma) (41, 82). The process of moving to the terrestrial environment was accompanied by physiological changes including altered gas exchange, reproduction, and osmoregulation; increased responses to ultraviolet radiation exposure without the protection of water; body changes to tolerate gravity pressure; and modifications of sensory organs to function in a dry environment (41, 82, 122). Details of these adaptations have been previously reviewed (41, 82). Following the transition to land, terrestrial arthropod species were able to diversify; there are now likely over 7 million extant species, representing a major component of the biodiversity of Earth. This review focuses on water homeostasis in terrestrial arthropods, ranging from how individuals detect water sources to how organisms respond to varying internal levels of water and the impact of drought on ecological interactions. A great deal of research is devoted to how insects locate food sources or mates, but these activities are less urgent than maintaining water balance. During hot and arid periods, a terrestrial arthropod can die in as little as an hour if water stores cannot be replenished (12). Arthropods have particularly high water loss rates because they are small, and smaller organisms have higher surface area to volume ratios that pro

Answer 1

Terrestrial arthropods adapted to life on land by developing an exoskeleton for support and to prevent water loss, as well as specialized respiratory systems like book lungs or tracheae for breathing air. They have segmented bodies and open circulatory systems with hemolymph, with different respiratory strategies for aquatic and terrestrial environments. These adaptations have contributed significantly to the diversity and success of arthropods on Earth.

Step-by-step explanation:

Adaptations of Arthropods for Terrestrial Life

As arthropods transitioned from aquatic to terrestrial environments, they developed numerous adaptations to overcome the challenges posed by the new habitat. One of the key adaptations for life on land was the evolution of an exoskeleton, which provided both support and desiccation resistance in the absence of water's buoyancy. Additionally, terrestrial arthropods evolved specialized respiratory structures such as book lungs or trachea to facilitate gas exchange with the air. These adaptations were vital for arthropods to not only survive but also diversify on land, as they are critical for maintaining water balance and enabling breathing without gills.

Arthropods are well-known for their segmented bodies, which can be fused into functional segments such as a head, thorax, and abdomen, or a cephalothorax and abdomen. Supporting these bodily functions, arthropods have an open circulatory system with hemolymph to distribute oxygen, and for those in aquatic environments, gills with a large surface area are used for gas exchange. For terrestrial species, however, different strategies are employed, such as the aforementioned book lungs and tracheae. Invasive terrestrial arthropods have further demonstrated their adaptability, showcasing diverse life-styles and high reproduction rates that have led to ecological and economic impacts around the globe.

In the grand scale of evolutionary history, these physiological and structural changes in arthropods have enabled them to become one of the most diverse and ecologically significant groups on Earth. It is crucial to appreciate how these adaptations have contributed to the evolutionary success of arthropods, influencing their role in various ecosystems and their capacity to invade new environments.