Language
Country/Area
No result found
Strange variation in island organisms: Why are their body shapes so unique?
The phenomenon of island biological variation, or island syndrome, refers to the fact that species living in isolated environments have morphological, ecological, behavioral and physiological characteristics that are different from those of the same species on the mainland. Shows a significant difference. On these isolated islands, the lack of large predators and herbivores, coupled with a stable climate, has led to changes in the way organisms adapt to cope with ecological pressures.
Organisms evolve different characteristics in different ecological environments as a result of natural selection, and island ecosystems have become the most distinctive laboratories.
Ecological drivers
Island ecosystems are generally unable to support the biomass required by large predators, which reduces predator pressure on prey and makes morphological and behavioral adaptations of prey species less important. In addition, isolated islands tend to have lower biodiversity, which results in less competition between species and less need for species to occupy distinct ecological niches.
Characteristics of Island Syndrome
Body size
The body sizes of island organisms tend to show different trends: small mammals may increase, while large mammals may decrease. This phenomenon is called Foster's rule, and insular gigantism often occurs in birds and reptiles.
Athletic ability
Because island prey face little predation risk, their evasive behavior becomes less important. For example, some island birds lost the ability to fly, which allowed them to focus on evolving stronger bone structures rather than maintaining flight muscles.
Adaptive Color
Due to reduced sexual selection, island species also tend to become more plainly coloured. For example, male white-winged flycatchers on some islands have black plumage, while their mainland counterparts have bright blue plumage.
Reproduction
In island ecosystems with limited resources, parents often choose to have fewer offspring to ensure that each offspring can receive higher care investment, thereby increasing its chances of survival.
Brain size
For some island species, the relative brain volume of these species decreases due to the reduced risk of predation in their living environment, but this does not affect their competitiveness in the ecosystem.
Behavior
Island species are often more docile and more tolerant of invaders. This change in behavior reflects the relationship between the environment and predation pressure.
Impact on conservation
In the past, when alien species entered island ecosystems, they often had devastating effects because island organisms lacked coping mechanisms against predators. Take the dodo in Mauritius, for example. The dodo faced extinction when humans introduced dogs, cats, pigs and other exotic species to Mauritius in the 17th century.
Thinking about the future
The adaptation and evolution of island organisms is not only a manifestation of natural selection, but also an important part of the earth's ecological diversity. So, in the face of environmental change and the impact of human activities, can the unique organisms of many islands continue to maintain their unique evolutionary characteristics?
