What are the different types of customizations

A evolutionary adaptation, in scientific terminology as adaptation is a characteristic of an organism that is advantageous for its survival or its ability to reproduce and that has arisen through natural selection for its present purpose.[1] In this context, a characteristic can be both a morphological peculiarity and a behavior. For a trait to be adaptive it must be hereditary; H. have a genetic basis.

Characteristics that are advantageous for the organism, but whose origin goes back to a different purpose, are called Exaptations designated.[2] The alternate term used for it Pre-adaptation is often avoided today because it gives the wrong impression of a goal-oriented development towards the new purpose. An exaptation would be, for example, the feather in the wing of the bird, which was created in flightless reptiles (originally for thermal insulation), i. H. was already present in the evolution of birds and was redesigned for the new purpose. Evolutionarily neutral or harmful traits are sometimes referred to as "adaptation" or "disaptation"; however, these terms are not commonly used.

In principle, evolution is not purposeful, but is based on random changes in the genome, which lead to changes in the phenotypes, which in turn have to prove themselves in a given environment. However, since a directed selection is also effective in addition to the random mutation, it makes sense to speak of adaptations.

The sum of the adaptations of the organisms of a species defines its ecological niche. Through acclimatization, living beings can adapt to certain environmental factors within the limits set by their genetic make-up. The different possible phenotypes of a genotype are referred to as its response norm. Adaptations are always made to the current environment. As a result, a feature can also lose its adapted character when the environment changes. Originally adaptive features, which now become disadvantageous in a changed environment, are also referred to as maladaptation (also: maladaptation). If an organism lives in an unpredictable, changeable environment, high genetic variability or a wide response norm can itself be an adaptive characteristic.

The environment of an organism is not only the abiotic conditions and factors, but also the other living beings with which it lives together - including its conspecifics. Accordingly, organisms also develop adaptations in response to these living beings, e.g. B. Fast running ability to escape predators. Since the other organism can also adapt, it can lead to feedback. One speaks here of Coadaption. Co-adaptations can lead to symbiosis or mutualism if they are beneficial for both partners. In other cases they often lead to an evolutionary "arms race".

As a rule, an organism in its natural environment does not have to adapt to a single factor, but to many at the same time. These requirements can conflict with each other. The actual adaptations therefore usually do not correspond to the technical optimum for the respective function, but are based on compromises. Several ecological optima to which an adaptation would be advantageous may well exist within the habitat of a population. Adaptations to one function lead to disadvantages in the other. Since the respective population is genetically related, the compromises in the adaptation can even lead to the fact that the actual population misses both optima. If some organisms are particularly well adapted to a combination of factors, this advantage is lost again in the next generation when they are paired with differently adapted ones (the factor is referred to as gene flow in population genetics). In this case one speaks of the “disruptive” selection having an effect on the population. Disruptive selection can lead to the division of a population into several sub-populations, and thus ultimately to the formation of new species.

heat

cold

  • periodic leaf fall
  • Homoiothermia (mammals, birds)
  • Mammals or birds can use thick fur / plumage to protect them from the cold. For many mammals in the temperate and polar latitudes, the change of coat is important, as a thicker winter coat protects these animals from heat loss. For some mammals such as the ermine, the change of coat also serves as a camouflage.
  • Most marine mammals and penguins, on the other hand, have a layer of fat that insulates them from cold sea water. In the case of whales and seals, this layer is called the bubbler. Fur seals, however, serve to isolate air pockets, this also applies to sea otters, which do not have an insulating layer of fat, but very fine, dense fur.
  • Antifreeze
  • Resistance to freezing
  • Cave construction
  • Hibernation

dryness

  • Resistance to drying out (mosses)
  • periodic leaf fall
  • Water storage (succulents)
  • Waterproof body cover
  • Formation of concentrated urine or uric acid

wind

Above all, strong wind harbors the risk of being blown away from the habitat.

  • Loss of wings (some butterflies)
  • Corresponding growth of the trunk in trees to avoid twisting, demonstrable by the thickness of the annual rings

flow

Above all, strong currents harbor the risk of being washed away from the habitat.

  • Streamlined body (trout), see also streamlined shape
  • Holding devices (stonefly larvae, mussels)
  • Hiding under stones (caddis fly larvae)
  • Slime formation (bacteria)
  • Increase in body weight
  • Reducing the water resistance
  • Suction cups

Darkness

Darkness renders one of the most important senses, the sense of sight, worthless. Cloudy water has a similar effect.

Lack of food

Lack of food reduces - in addition to the threat to existence - the rate of reproduction

Heavy metals

  • Neutralization of heavy metal ions through chelation with organic acids

Antibiotics

Predators

Detail from a butterfly wing, here the eyes of larger animals are simulated

Web links

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  1. ↑ M.R. Rose & G.V. Lauder (1996): Adaptation. Academic Press (San Diego, USA).
  2. ↑ Stephen Jay Gould, Elisabeth S. Vrba (1982): Exaptation - a missing term in the science of form. Paleobiology 8 (1): 4-15.

See also