The key factor for generation of diversity on Earth is evolution, as I told you in my previous blog Diversity on Earth: How is it created and maintained?
I also mentioned that environmental disturbances play a major role in the initiation of evolution. In this blog, I’d like to throw some light on exactly what role environmental factors play, and what it leads to.
Every organism of a particular area tend to face the same kind of stresses: what food to eat? Where to sleep? How many offsprings to produce? What to do when it gets too cold? What to do when it rains a lot? How to escape predators?
All of these questions are answered by the organism by developing certain mechanisms for itself. Such responses to environmental stress by an organism, that helps it survive better are called adaptations.
What makes the study of adaptations so important is the sheer variety on Earth. Every organism has tried to deal with a particular stress differently, come up with a different response, that triggered evolution, and eventually gave it its place in the ecosystem. The variety of adaptations is what has lead to the development of the “system” that makes nature so conditional (as already explained in Earth’s Paradox: Greater complexity, more stability) and this variety is what eventually leads to diversity of life.
For example, all the organisms living in the cold, polar regions have come up with different adaptations to continue surviving. While Polar Bears choose to hibernate during the cold winters, the Siberian Cranes choose to migrate to warmer regions in the south.
Some adaptations are common among organisms; taking the polar example again, all the animals living in cold regions tend to have shorter limbs and ears with respect to the size of their body, to conserve heat (called Allen’s Rule). They also tend to have a thick layer of blubber under their skin, to keep warm. Such common adaptations are present when the stress is a large scale stress.
Adaptations also govern what kind of food the organisms consume, and how they consume them. These adaptations are what have given rise to the food chain, the food web and the trophic levels in nature (read Humans: Earth’s most dominant species to know more).
Organisms also co-adapt with different organisms, to increase their chances of survival. A clown fish (like Nemo) is immune to the tentacles of a sea anemone, while other aquatic animals are harmed. So clown fishes find a survival edge in living within the tentacles of a sea anemone.
The examples are numerous. And that is it’s significance. The numerous examples of adaptations highlight the variety of life on Earth.
The whole process of diversity generation is a simple chain reaction;
Environmental stresses—>Adaptations—>Evolution—>Biodiversity—>Stability in the ecosystem.