How does adaptation affect the diversity of an ecosystem?
Answers
become better fitted to the environment as a result of natural selection. Adaptations generally occur in order to increase the fitness and thus survival of organisms. By being able to adapt to the changing environment, organisms are better able to survive and reproduce.
Adaptation can be considered at the species level, but a recent study, performed by Kelly et al., involving Tigriopus californicus has
shown that that may not be sufficient to accurately predict the effects of climate change on a species. T. californicus has isolated populations scattered through a wide latitudinal range. These populations have great disparities in terms of their thermal tolerance and their ability to adapt to a new thermal tolerance. This data suggests that in order to accurately predict the effects that a changing temperature and climate will have on a species, it is necessary to look at the variance in adaptation potential in different populations of that species.
Many people are under the impression that species require thousands or even millions of years to adapt. This article by Carl Zimmerman explains how evolution can actually occur in surges, a feature of evolution that proves very useful during periods of climate change. It is important to also note that evolution continues to occur long after climate change has stabilized. Delayed reactions continue to change allele frequencies and compositions of populations.
Phenotypic plasticity and the rate of climate change are important factors in determining if a species will be able to adapt.
The phenotypic plasticity of species of brown trout are heritable. If the rate of climate change is slow enough that organisms at the upper range of tolerance can survive, then there is a chance that the species can adapt over time by inheriting this tolerance.
The rate that a species can adapt is related to how drastic of a temperature change it could survive and adapt to. In the case of T. californicus, the fragmented population means that there is large variation in the species (and thus large potential for adaptation), but lower opportunity for adaptation within the individual populations.
A greater amount of variation is indicative of a population that can more readily adapt, as evidenced by this article showing that S. franciscamus,a species of sea urchin, is more likely to be able to adapt to increased carbon dioxide levels than the mussel species M. trossulus over the next 50 years.
A review published this year reiterated the idea that most organisms, marine or terrestrial, have only limited temperature ranges in which they can live, representing their plasticity. Evolutionary changes to this range are considered long-term. In this review, the focus is on Arctic marine organisms, which have extended their temperature ranges to include very cold temperatures.
An organism at the edge of its thermal tolerance may have more difficulty adapting.