Hawaii is not only for American biologists diagnosis rather than geographic destinations. To extreme physical diversity of some genera of plants and animals had always points to new possibilities for research and development. But as argued by Charles Marshall (UCB), who is also director of the Paleontological Museum of the University of Hawaii already has the best behind.
"Many colleagues think that the species in Hawaii are still developing, they have created a new subspecies and their morphological variants. This is to some extent true, of course, but the current trend is nepoměřitelný to how it looked before, millions of years ago. "It was mentioned in the past million years were the time when the Hawaiian Islands were biodiversity on top. Although it while looking at the flood of exotic flowers in the lush jungle looks, not looking at the dynamic melting pot of new species. Rather, we are watching a pair of thin air, in which millions of years ago was cooked something far more interesting.
Why is this so? California team evolutionary biologists warns that the archipelago of 95 coral and volcanic islands and 118 rocks and reefs in the Pacific Ocean almost continually shrinking size of their land. Slow coral growth and the absence of volcanic activity can be considered that the sea slowly eats away his part from the mainland. A islands (except the "Big Island", ie Hawaii) is gradually shrinking. This loss of solid ground course given the local flora and fauna in the environmental stress which gradually manifested in loss of species.
And this significant decline in biodiversity is continually taking place long before the islands became apparent to human activity, whether natives or colonists. The scientific work that does not put the blame for the decline in animal and plant species people today is a precious commodity. Besides, a study from Berkeley gained attention and an unusually wide-ranging evidence.
Data collected for the argument because evolutionary biologists for fourteen branched groups of animals (such as birds, insects, spiders, flowering plants), for each island or group of islands interconnected Hawaii. "On older islands, such as Oahu or Kauai, and today divided on four islands, which were once one island of Maui Nui is the most studied groups in the long evolutionary decline," says Marshall.
"These islands were once old is much greater than now. Developing new subspecies previously where they spread and expand, but to gradually shrinkable space must necessarily cause them to be snapped and congestion. And this effect led to their extinction, "says Marshall.
This conclusion is not in direct conflict with what biologists about Hawaii and its animal inhabitants thought. It was assumed that as spiders have not been able to occupy all the islands, that they are only gradually getting. And along with that, how will this isolated place to penetrate, their representatives will continue to diversify into new subgroups.
However, as mentioned biologist Ying Jun Lim, who examined the representation of each group in terms of genetic diversity and DNA, the process of spreading and diversification have long passed. "The beauty of the islands of Hawaii is in their geological setting. Biota each site is not definitive, it is constantly dynamically changing process. The islands of Hawaii, we can in this regard, be seen as a series of images taken during a trip to the past. "
The oldest volcanic islands of the Hawaiian archipelago, as it is known today, are bathed by the sea has about 6 million years. When hot magma gave rise to Kauai and slabs of oceanic tectonic shift he gradually, like other emerging islands, edged northwest.
The youngest and newest island of Hawaii, which was formed about 1.3 million years ago. Each of the newly formed island was colonized by plants and animals of the older islands, which led to the rapid filling of diverse ecological niches islands. Haleakala endemic plants and birds šatovníků series reached its peak (Island of Kauai) 3 million years, and beetles for 4.5 million years.
Author: Radomír Dohnal
Source: Ekolist.cz
