Relative nature of fitness on the example of cacti, chameleons and turtles

Adequacy is one of the most important factors of evolution. What features does it have? How does the relative nature of the fitness of a cactus, a chameleon, a turtle manifest itself?

Organisms and the environment

Each separate species of living creatures has its own habitat. Within its limits, various factors operate, which have special characteristics, for example, a certain temperature of the air, salinity of soils or water, certain inhabitants.

To survive in a particular environment, the body must adapt to it. Anyone who does this as efficiently as possible can survive and have offspring. Plants, animals and even humans in the course of evolution have developed various tools that help them to adapt.

These instruments were gradually formed. Species that had some advantage in structure or color, survived under certain conditions better than others. Useful traits were inherited and became more pronounced. Over time, the necessary signs have become characteristic of all representatives of the species or population.

Relative fitness

Adaptability refers to the presence in animals or plants of signs that correspond to their lifestyle and the environment in which they are located. For example, the body of the fish has a streamlined shape and is covered with mucus in order to move more easily in the water. Arctic bears have white color to maximally merge with the environment.

However, the developed auxiliary mechanisms of representatives of wildlife are not absolute, but relative. Why fitness is relative? It's simple. If the body adapts to the specific environmental conditions, then to other conditions it may not be prepared. Environmental factors usually change faster than organisms that need to go through at least a few generations for this.

The relative nature of fitness is also manifested in the fact that, having a reliable means of protection from some enemies (bright color, spikes or poison), you can get on the net to others. Thus, the poison of many snakes affects small prey, discourages large mammals, but does not stop hedgehogs and mongooses that feed on snakes. We consider the following examples in more detail.

Cacti

An excellent example of survival in harsh conditions is demonstrated by plants of the family of cacti. They feel great in an environment unbearable for many living things. Plants are common in deserts and semi-deserts, mountains, savannahs, arid forests.

A powerful fleshy stem allows you to accumulate a lot of moisture from the air, and the leaves, modified into thorns, do not let it evaporate. In addition, sharp spines scare off those who wish to eat cactus. Strongly developed roots, reaching to deep underground waters, saturate the plant with water.

Thus, the plant is fully prepared for life in regions where precipitation is extremely rare. The relative nature of the fitness of the cactus lies in the fact that when the conditions change, for example, in the event of prolonged downpours, the plant may die from excessive water intake into the body.

In the room, all the benefits of cactus are lost and become neutral. A powerful stalk and thorns will no longer carry in themselves those important functions for survival, only the aesthetic aspect will remain.

Chameleons

Most of the time, chameleons spend on trees, chameleons help them to climb flexible limbs. The fingers of the animals grew together, forming two almost opposing groups (resembling a claw in appearance), a tail twisted and long - all this makes it possible to easily grasp the branches and move along them.

The relative nature of the chameleon's fitness is precisely its color. The natural color of the animal as much as possible masks it under the environment, making it invisible to predators. But chameleons often change color, using it as a means of communication.

Some types are capable of repainting in almost all colors. So they express their reaction to the change of lighting, humidity or the appearance of other animals. At the moment of danger, the "lizard" experiences stress and can become bright red or yellow, betraying itself, instead of merging with the situation and hide.

Turtles

Reptiles unique in their structure are turtles. The animal's body is in a dense shell, covered with skin or horny shields. It is a little like a shell, because it consists of the upper and lower parts.

The tortoise is not just located inside the shell, it represents with it a single whole. The upper part of the "frame" has grown together with the spine of the animal, the lower part is formed by the clavicle and abdominal ribs. A turtle can not be pulled out of the "house" without crippling it.

In case of danger, the animal hides its head and limbs inwards. How does the relative character of fitness manifest itself in this case? Predators can not gnaw a shell or pick out a tortoise from it. But the eagles raise it high above the ground, release it so that the shell will crumble, and then eat up their prey.

Conclusion

The adaptability of organisms is the correspondence of their external and internal structure, behavior to the environment in which they live. It is formed in the course of a long historical process and is an important factor in evolution.

The relative nature of fitness is that the characteristic features of an organism can help it only under certain conditions and situations. When changing external factors, adaptations can be ineffective, and sometimes harm their master.