Questa foto di Madagascar è offerta da TripAdvisor.
Some of the plants and animals present on the island today are the result of adaptation from the original, marooned Gondwana stock.
Ancient groups such as the ferns, cycads, palms and screw pines, and primitive reptiles such as the boas and iguanids, are descendants of this relic community.
Questa foto di Madagascar è offerta da TripAdvisor.
Yet the magic of Madagascar is that a select band of species has enriched the community by arriving since the break-up.
Flying, swimming, journeying as seeds or riding the floodwaters of the east African rivers in hollow trunks, wave after wave of more recent plants and animals came from over the horizon during a period of 100 million years, bringing with them the latest adaptations from the big world beyond.
Questa foto di Madagascar è offerta da TripAdvisor.
Colonisers, such as the lemurs and carnivores, may have had a helping hand from a partial land-bridge which is thought to have appeared from beneath the waves of the Mozambique Channel about 40 million years ago.
Yet, whatever their mode of transport, upon landfall each species spreads outwards in every direction, through the tremendous range of habitats, changing subtly as they encountered new environments, frequently to the extent that new species were formed.
Questa foto di Madagascar è offerta da TripAdvisor.
This evolutionary process is termed "adaptive radiation" and it results in the creation of an array of new species found nowhere else.
The patterns in the island's diversity tell us something of the timing of these colonisation.
A large number of unique succulent plants indicates an early arrival from Africa in a dry west, followed by a radiation eastwards ending in the rainforests.
On the other hand, the two Malagasy pitcher plants found in the east probably arrived at about the same time as people, and from the same direction.
From this great evolutionary melting pot has emerged the bewildering array of animals and plants that bless Madagascar today; most are unique and countless still await discovery.
Questa foto di Madagascar è offerta da TripAdvisor.
http://magicnamibia.blogspot.com
http://magicbotswana.blogspot.com
http://magicsouthafrica.blogspot.com
http://magicmadagascar.blogspot.com
http://magiadinamibia.blogspot.com
No comments:
Post a Comment