Darwin, Galapagos mockingbirds, evolution


This is a Galapagos Islands mocking bird video.

From the BBC:

Darwin’s specimens go on display

Two mockingbirds, which are said to have helped Charles Darwin develop his theory on evolution, are to go on public display for the first time.

The specimens, gathered by Darwin from the Galapagos, are said to be the “catalyst” for his transmutation theory – how one species changes into another.

A variety of differences between the specimens led to him questioning the “stability of species”.

The birds will go on show at London’s Natural History Museum next week.

The mockingbirds will feature in an exhibition dedicated to the pioneering work of the naturalist, which is part of Darwin200, a national programme of events running throughout 2009, celebrating the 200th anniversary of his birth.

“What is fantastic about these two birds is that visitors will be able to see for themselves the crucial differences that Darwin saw,” said Jo Cooper, the museum’s bird curator.

The mockingbirds were collected during Darwin’s five-year voyage on board HMS Beagle, which was captained by Robert FitzRoy.

‘Common ancestor’

One of the birds was captured on the island of Floreana, while the other was gathered from another Galapagos island, which is now called San Cristobal.

As a result of an earlier visit, Darwin knew that there was only one species of mockingbird in South America, yet he found a different species on each of the islands in the Pacific Ocean archipelago he visited.

From this, he reasoned that all mockingbirds in the world had descended from a common ancestor, because they shared a number of similarities with each other.

This ultimately led Darwin to the conclusion that all organisms on Earth had common ancestors.

Recent shifts in sea level, particularly the lows, may have had a major influence on evolution in the Galapagos, according to new research: here.

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9 thoughts on “Darwin, Galapagos mockingbirds, evolution

  1. Galapagos Penguins Need ‘Condos’ as Shelter From Global Warming

    By Jeremy van Loon

    April 27 (Bloomberg) — The Galapagos Islands, renowned for rare animals that inspired Charles Darwin’s theory of evolution, may have to create special shelters to save species from global warming and rising sea levels.

    Scientists who met there last week decided the indigenous penguin needs “condos” built in cooler, higher areas to nest more safely, Giuseppe Di Carlo, marine climate-change manager at Conservation International, said in an interview. Shadier bushes would protect plants and animals such as birds and tortoises that produce too many of the same sex in hotter weather.

    “The challenge that we’re facing is a high rate of extinction,” Di Carlo said from the conference. “This will have consequences for the islands’ human population as the economy here is based almost entirely on tourism and fishing.”

    The Ecuadorean territory 1,000 kilometers (600 miles) west of Guayaquil in the Pacific is one of the few places on Earth where tropical and cold-water species of fish and animals co- exist, helped by a meeting of sea currents, including the Humboldt. Climate and species scientists who gathered there 150 years after Darwin published “On the Origin of Species” are studying how to help the islands adapt to climate change.

    Because of their location, the Galapagos may be more affected by climate change. The El Nino effect, a warming of equatorial waters in the eastern Pacific that affects ocean currents and climate around the world, may become more intense and variable with global warming, Di Carlo said.

    Rising Sea Levels

    Ice melting near the poles may cause sea levels to rise at least 50 centimeters (20 inches) by the end of this century, according to scientific findings presented to the United Nations in Copenhagen last month. The world is likely to warm by 2.5 degrees Celsius (4.5 degrees Fahrenheit) in the same period, Rajendra Pachauri, chairman of a UN panel that coordinates climate-science research, said.

    Galapagos animals most threatened include the flightless cormorant, whose nests are susceptible to flooding from higher sea levels, a giant tortoise, the marine iguana and the Galapagos penguin, according to Conservation International, an environment group based in Washington.

    The penguin, spheniscus mendiculus, is the only one of its kind to live on the equator due to the cool water and air temperatures from ocean currents. One of the smallest penguins, it weighs about 2.5 kilograms (5.5 pounds), measuring about 50 centimeters and eats sardines and mullet.

    Penguins Prefer Cooler Mating

    Penguins are very “fussy” about where they live and are unwilling to move their nests, Di Carlo said. Scientists say they want to provide them with more shady homes of stone or concrete because the birds mate better in cooler temperatures.

    An indication of how animals and plants in the Galapagos will respond to climate change is provided by El Nino. If the phenomenon becomes stronger, that may harm the fish population, hurting fishermen’s livelihoods and damaging the tourism industry, which relies on diving. Fishing and tourism make up 90 percent of the Galapagos economy.

    The Galapagos have a population of about 40,000 people, a 40-fold gain in the past half-century. Isabella, the largest island, is still being formed by volcanic activity, and most of the rocky archipelago was designated a national park by Ecuador.

    The islands attract tour boats, regulated by Ecuador, and areas to walk and visit on Isabella and elsewhere are restricted by park authorities to protect flora and fauna that include the blue-footed boobie.

    Other island ecosystems affected by human-caused changes include Macquarie, a United Nations World Heritage Site, where plants and animals introduced by humans as a source of food have overrun native species.

    Island chains such as the Maldives, popular with tourists and honeymooners, also are in danger of being submerged by rising waters in the coming years amid climate change.

    To contact the reporter on this story: Jeremy van Loon in Berlin at jvanloon@bloomberg.net.
    Last Updated: April 26, 2009 18:01 EDT

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