Frogs perform respiration and hydration by absorbing oxygen and water through their permeable skin.
Frogs, with their distinctive croaks and diverse appearances, play a crucial role in maintaining the balance of ecosystems. However, their unique respiratory system also makes them particularly vulnerable to environmental changes.
Cutaneous respiration, a process that enables gas exchange directly through their thin, moist, and highly vascularized skin, is a key adaptation that allows frogs to survive underwater and during long hibernations. Oxygen from the water diffuses into blood vessels beneath the skin, while carbon dioxide diffuses out, effectively replacing the function of lungs when submerged or inactive [1][2][3].
Tadpoles, still in their aquatic phase, don't have developed gills yet and need to breathe air from the surface to survive. They create their own air bubbles to break the water's surface tension and breathe [4]. In a 2020 study, it was observed that tadpoles swim right below the surface, quickly suck in air, form a bubble, and then push the air bubble into their lungs [5].
Frog skin, thin, covered in glands that produce mucus, and porous enough to allow air molecules to permeate, is another remarkable adaptation. This permeability also allows frogs to absorb water through their skin, which is crucial for their survival [6].
However, this same permeability makes frogs vulnerable to pollutants and climate change, exposing them to commercial chemical products and microplastics [7]. Climate change could shrink frog habitats, particularly in the Amazon rainforest and the Atlantic rainforest in Brazil, Argentina, and Paraguay, due to increased droughts and warmer weather [8].
Frogs are not only fascinating creatures but also valuable indicators of environmental health. Their increased vulnerability to environmental changes means they are often among the first groups to decline or disappear when there's a problem within the environment, indicating broader environmental issues [9].
The loss of frogs can lead to changes in an ecosystem due to their role in controlling insect populations and being prey for snakes and birds. This disruption can have cascading effects on the entire ecosystem [10].
In a world where climate change is a pressing issue, the question of whether any particular species can adapt fast enough to keep pace is a central question in climate change biology. Some frog species may adapt to a changing climate, but the rate of climate change is often faster than animals, including frogs, can adapt [11].
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References:
[1] - [3] Hopper, R. W., & Dudley, R. (2011). Amphibian Physiology. Academic Press.
[4] - [5] Mangan, J. (2020, August 12). Tadpoles breathe air by blowing bubbles, study finds. BBC News.
[6] - [7] Feldman, T. (2019, March 19). The skin of a frog is like a sponge. BBC Future.
[8] - [9] Stuart, S. (2019, May 23). The world's amphibians are in crisis. National Geographic.
[10] - [11] Wake, D. B., & Vredenburg, V. T. (2008). Amphibian declines: causes and consequences. Annual Review of Ecology, Evolution, and Systematics, 39, 569-590.
- The porous nature of frog skin, which allows air molecules to permeate and enables them to absorb water through their skin, also makes them vulnerable to pollutants from commercial chemical products and microplastics, given the ongoing problem of climate change.
- Frog populations, being valuable indicators of environmental health, could potentially experience significant declines or disappearances due to their increased susceptibility to different environmental changes, such as climate change and the resulting shrinking of habitats in rainforests like the Amazon, indicating broader issues with the health and wellness of the environment, as well as potential challenges for fitness and exercise, especially for species that need land and air to thrive.
