Wednesday, May 18, 2011

The Galapagos: An Evolutionary Wonder

Check out the BBC documentary at the end of this entry. 


Galapagos (Google)


The Wasteland of Life: The Origins of the Galapagos Archipelago

From a fiery pit burst forth the world of the Galapagos Islands. In the Pacific Ocean, a volcanic hotspot boiling at over 2,000 degrees gave birth to the layers upon layers of lava, becoming
barren rock inhospitable to life that, ironically, is responsible for a biodiversity found nowhere else. This chain of 13 main islands demonstrates a natural phenomenon that drastically alters our perception on nature. Here is a world of extremes where each island varies in species diversity, environmental conditions, and means of adaptations.
The Marine Iguana underwater
           Over 500 species are possible because of the hot and cold undercurrents that allow for such high diversity. From high and low, wildlife inhabits the Galapagos creating a complex ecosystem with an elaborate food web. Garden eels, Eagle rays, and Scalloped Hammerhead sharks swam in, while seabirds— attracted to the high level of fish— made this place home. The most miraculous occurrence is the arrival of and evolution of land animals. Those animals that survived the flashflood were abandoned on a wasteland. One type that adapted well was the marine iguana.  They were able to take on the temperature of their environment and thus are used to the heat extremes. The reptiles that were once endothermic evolved to a higher level of amphibian/reptiles; they are now exothermic and can swim underwater for up to fifteen minutes to catch food with its new food resource being algae. No other iguana on this planet shares this unique capability. Such evolution further took place in the diversity of interactions.

Different Island, Different Story of Interactions

Sally Lightfoot crab (Google)
            Where nothing existed, life came to be along with an abundance of species-habitat interaction and species-species interactions. On each island the habitats and interactions are different among species. The different types of soil (textures and depth) and vegetation determine the animals that will live in that habitat.
          Each island is a world of its own, a characteristic resulting from the distance and age among them. When tectonic plates glide over a hotspot, a new island dawns and eventually they move away from each other becoming dormant. From West to East exists a chain from young to old impacting the diversity of life that thrives on the islands. Of these, Fernandina is the youngest and most volcanically active. Fernandina is home to the marine iguanas that can be seen sunning on the rocks. Twelve times older is the largest island, next to Fernandina, Isabella, which was named after the Queen of Spain. It also has a wider range of diversity. Since it has more vegetation, reptiles can be found roaming around. 
Giant Tortoise (Google)
            Examples of interactions are prominent throughout both islands. The iguanas befriend the Sally Lightfoot crabs (parasites that groom them), while tortoises and finches develop a mutualistic symbiotic relationship. The Galapagos finch stands before the Galapagos giant tortoise, and the tortoise stretches out its neck to be cleaned of ticks. In this way, the tortoise is no longer beleaguered with the parasites and the finch has received a scrumptious meal (“Galapagos Tortoise”). While such peaceful interactions are ideal, predators are no strangers to the Galapagos Islands.
Hawk feeding on marine Iguana (Google)
On Santa Cruz, the second largest island of the Galapagos, the Galapagos hawk preys upon seabirds, insects, and female marine iguanas. One prime example of this interaction is that of the marine iguana and the hawk. In a burrow, the female iguana lays her eggs, a process that weakens her ability to guard herself and the burrow. From afar the hawk patiently waits for the moment she decides to return to the marina. The moment she abandons her safe haven, he attacks her by pressing her firmly against the hot sand, which results in heat exhaustion, killing the iguana. While the marine iguana cannot safely breed in this area, the Waved Albatross has found a safe habitat to do so.
Espanola further exemplifies the uniqueness of the Galapagos. The clumsy Waved Albatross breeds nowhere else.  Upon arrival, the male awaits the female for several weeks. Once both are present, a dance ensues consisting of beak fencing, fake preening, and lastly a bow. Nowhere else can the pristine beauty of the Galapagos be found, and yet this only first became acquainted with history in 1535.

How History Embraced the Galapagos
Waved Albatross Courtship (Google)
History was graced with the presence of the Galapagos in 1535 in a letter from father Tomas Berlanga, addressed to the King of Spain.  While the Bishop was sailing to Peru, the ship was swept off course and thus the crew came upon a place that resembled hell. Through his description, Galapagos was transformed into the underworld of a fantasy novel. His letter referred to the island as “a place where it seemed as if God had showered stones.” It was deficient of the resources they needed to survive, such as fresh water. Despite his complaints, the creatures dwelling in this foul land fascinated him: the turtles, iguanas, and birds. This discovery fascinated the Spaniards and eventually became a hideout for pirates as they attacked the Spanish. However, the knowledge of its existence endangered several species.

Humanity’s Inhumanity: Species Endangerment
            At one point in time the Galapagos harbored pirates, and although their reign ended in the 17th century, their impact upon the population growth was drastic. In their desperate search for oil, they preyed upon the majestic sperm whales. Their over hunting proved profitable for them but was costly to biodiversity. The sperm whales were wiped out but are now returning. However, such catastrophic events do not remain in the past and this issue is currently a growing environmental concern.
Google Image
            The fur seals’ “thick luxurious coat” is attracting the greedy eye of hunters.  Such greed has devastating consequences upon the seals, and thus they are at the brink of extinction. Giant tortoises share a similar misfortunate fate. Their meat was valuable for ship travel and as a result their species was almost eradicated. The cruelty persists in the 21st century through migration of people, tourism, and overfishing (“Environmental Issues of the Galapagos”).
            In search of better professions, the islands are being invaded at an alarming rate.
The current population that lives on the island is “more than 20,000” and they are “doubling every eleven years, which means that there will be 40,000 people on the Galapagos Islands by 2014(“Environmental Issues of the Galapagos”). The environment is thus being plagued with garbage which especially pollutes the environment once burned. Furthermore, the people are beginning to exhaust the natural resources. The bleak future of the Galapagos is propelled by the influx of tourists.
         Drawn to the mystery and exoticism of the Galapagos, tourists flood the islands. The joint pressures of residents and tourism lead to “unknown numbers of invasive plant and animal species driving out native species…and habitats are degraded at alarming rates” (“Conservation”). The population growth has had severe effects on the islands’ ecosystem.  Their needs grow in congruous with their population, if not faster.
            The growing population’s insatiable hunger for more has led to overfishing.  The fishing industry provides innumerous jobs to migrants. Sea cucumbers and sharks are in imperil, “both popular in Asian markets for their aphrodisiac or medicinal qualities” (“Environmental Issues of the Galapagos”). While the National Park attempts to enforce their regulations, their good intent is met with opposition from the fishermen. The strife between the two parties is far from over. Fortunately, “the Galapagos Islands are still home to most of the species that lived there before the arrival of humans” (“Conservation”). Furthermore, their everlasting contribution to science is priceless.

And the Theory of Evolution is Born
Finch (Google)
In 1835 the ship’s naturalist, Charles Darwin, was thoroughly immersed in his fascination with the Galapagos. He made the “conviction that the entire earth is in flux.” He began questioning his perception on nature and began collecting specimens from different islands in hopes of understanding the mysteries he encountered. During his exploration he noted that different islands varied in climate and species. On Floriana Island, Darwin met an English man who informed him that the shapes on the shell o f the tortoise show their origin; Tortoises, thus, are an incontestably strong example of evolution in the Galapagos, since the most successful at survival are the ones that “spread throughout the island.” Not only did the tortoises intrigue him, so did the diversity of finches. He collected several finches and took them back to this ship to study.
Tortoises, he noticed, varied in size and shape according to their habitat (or which island they were on). For example, the lush places were home to the Domeback tortoises, the largest of the races, and the Saddledback tortoises were smaller and are located in the drier islands. As for the finches, there were thirteen different species with different sized beaks for specific purposes, each related to their niche. For example, the ones with a pointy beak needed it to get small insects. Overall, tortoises and finches led him to his famous evolutionary theory.

Galapagos: A World in Itself
The Galapagos is a tapestry of life, interwoven with a diversity of species encountered nowhere else on Earth. It is “a natural laboratory for evolution” and the place accredited by Charles Darwin for inspiring his Theory of Evolution. However, the Galapagos is victim to mankind, raising important environmental issues. Overfishing and the influx of tourists and local inhabitants are increasing the degradation of the region and species endangerment.  Hopefully, with stringent regulations and education of the masses on the importance of the ecosystem, the lives and habitats of these species will be safe from extinction.


References:
Note- Most of the information I garnered from watching documentaries.





"Conservancy." Galapagos Conservancy. 9 Apr. 2008            
      
"Environmental Issues of the Galapagos." Galapagos Islands. 2007. Ecuador 
       Explorer.Com Guide to Ecuador, Quito,. 8 Apr. 2008             
        
"GaláPagos Tortoise." Wikipedia. 9 Apr. 2008. 9 Apr. 2008                
               
"Santa Cruz Island." Encyclopædia Britannica. 2008. Encyclopædia Britannica     
       Online. 9.  Apr.  2008  



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Sand-Dollared Cataract by Sofia Mitchell is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

1 comment:

  1. I love the galapagos and I the scientist in me would love to go there one day; it's a shame the Ecuadorian government didn't realize there would be a problem until the problem arose. This is going to be a problem with pacific islands just like the galapagos.

    Do you know how travel to the galapagos works? If it is only open to tourists for a certain time out of the year? And they should put restrictions or levies of some sort on residents...who probably aren't even from Ecuador. It's a shame.

    ReplyDelete