Question

Both aquatic and terrestrial organisms must have __________ across which gas exchange can take place.

Answer 1

Aquatic and terrestrial organisms must have respiratory structures like gills in aquatic species or lungs and tracheae in terrestrial species for gas exchange. Small multicellular organisms may rely on diffusion across their surface membrane, while larger animals need more complex systems.

Step-by-step explanation:

Both aquatic and terrestrial organisms must have specialized respiratory structures across which gas exchange can take place. In aquatic environments, organisms may utilize gills like mollusks and annelids, which are filamentous structures allowing for the exchange of gases with the water. Terrestrial animals have evolved various respiratory adaptations such as the lungs in mammals, book lungs in arachnids like scorpions and spiders, and tracheae in insects that facilitate gas exchange with the air. Furthermore, gas exchange in small multicellular organisms can occur through direct diffusion across their surface membranes when every cell is in proximity to the external environment, ensuring efficient respiratory function.

For example, flatworms which have a flattened body shape, allowing for an increased surface area and therefore more efficient diffusion across their body surface. Similarly, earthworms and amphibians can utilize their moist skin, with a rich network of capillaries just below the surface, to facilitate gas exchange with the environment. In comparison, larger organisms require more complex respiratory systems, such as lungs or extensive gill structures, to efficiently deliver oxygen throughout their bodies.

Answer 2

Both aquatic and terrestrial organisms must have a respiratory system across which gas exchange can take place

A respiratory system is a biological system which consists of definite organs and structures used for gas exchange in animals and plants. In most aquatic organisms such as fish, the respiratory system consist of gills in which gas exchange takes place. The gills is immersed in a watery environment and water flows over it by a variety of active or passive means. In terrestrial organisms, gas exchange takes place in the lungs.