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But most of the Galapagos life forms reached the islands by accident, and all had a long sea voyage. During that trip, both plants and animals were exposed to saltwater, drying winds, and intense sunlight. … Galapagos reptiles are also more likely than land birds or mammals to be able to survive under these conditions.
Organisms that are capable of colonizing islands naturally are typically adapted to be dispersers, are small and numerous in their original habitat and have a propagule (seed, larva, spore, etc.) that can be dispersed over water, through wind or vectored by an animal from the mainland.
After surveying the coasts of South America, the ship stopped over in the Galapagos Islands. During his visit to the islands, Darwin noted that the unique creatures were similar from island to island, but perfectly adapted to their environments which led him to ponder the origin of the islands’ inhabitants.
The circumstances in the Galapagos — frequent interisland travel due to short distances between islands and interbreeding — prevent the finches from truly forming distinct species. It makes more sense to classify the birds as a single species of ground finch with ecologically driven variations, Zink says.
In other words, beaks changed as the birds developed different tastes for fruits, seeds, or insects picked from the ground or cacti. Long, pointed beaks made some of them more fit for picking seeds out of cactus fruits. Shorter, stouter beaks served best for eating seeds found on the ground.
Nearly 9,000 species are found on the islands and their surrounding waters, many of them endemic.
Galapagos is located on the Nazca tectonic plate.
This perpetually moving plate is heading eastward over the Galapagos hot spot and has formed the chain of islands. The islands were formed through the layering and lifting of repeated volcanic action.
There are 19 resident species of which 5 are endemic. One endemic species is the Galapagos penguin (Spheniscus mendiculus) and the only species of penguin to exist north of the equator and nest in the tropics (Jackson 1999).
His discoveries included four different species of giant ground sloth (some of the largest land mammals ever to have lived), a gomphothere and the remains of an extinct horse. Many of Darwin’s fossils survive, at the Museum and elsewhere.
In this island Darwin noticed that most species were similar but different from other in the other islands, giving enough evidence to theorize that species change and this is related to their feeding and surroundings. He collected finches that helped him to understand this resolution.
The Galapagos Islands were formed millions of years ago by volcanic activity. Discover how tectonic shifts created the islands and how deep below the sea, organisms thrive in the vicinity of hydrothermal vents.
The plant and animal life of the Hawaiian archipelago is the result of early, very infrequent colonizations of arriving species and the slow evolution of those species—in isolation from the rest of the world’s flora and fauna—over a period of at least 5 million years.
To put it in perspective, Hawaii has no poisonous land snakes, bears, crocodiles, hippos, leopards, komodo dragons, hyenas, lions, tigers, poisonous dart frogs, rhinos, etc.
Goats were successfully introduced to Santiago Island, which sits in the middle of the Galapagos archipelago, over the 1920s and 1940s. The goats grazed the island mercilessly, causing erosion, threatening the survival of rare plants and trees and competing with native fauna, such as giant tortoises.
By the early 1990s, the goats had destroyed the forest and thus eliminated the shade and water supply so vital to the giant tortoises. Other native and endemic species, including birds, insects, and plants, were also negatively impacted.
Land iguanas, lava lizards, geckos and harmless snakes can also be found in the islands. … Some of these are found only on one island. The most outstanding are penguins, which live on the colder coasts, Darwin’s finches, frigatebirds, albatrosses, gulls, boobies, pelicans and Galápagos hawks, among others.
The blackberry was first introduced by humans to the island of San Cristobal for agricultural purposes. It was rapidly spread to other islands like Isabela, Santa Cruz and Santiago by native bird species who fed on the fruit. Soon enough they were responsible for the localized spread of this plant.
These are 10 of the most unwanted and threatening invasive species throughout the world.