A real goat, in the Charlie Brown sense of the word. David Rochkind/Polaris, via NYT.
"War in the Pacific: It's Hell, Especially if You're a Goat" was a fun read after Darwin's description of the Galapagos in The Voyage of the Beagle (reviewed on Amazon). This article describes a new extermination project targeting goats on the Galapagos. These goats, interestingly enough, were introduced to the Galapagos in the 1800s by sailors, who used the goats as a food source when stopping by.
Invasive species have a particularly devastating effect on fragile island ecosystems. This is certainly true in the Galapagos, where many of the plants and animals that Darwin observed growing and frolicking, respectively, are now threatened by invasive species. The Galapagos are in many ways fortunate because many of the threatened endemic species are high profile, having become iconic of evolution thanks to the work of our very own Charles Darwin. The finches, tortoises, and marine iguanas, for example, are all threatened by introduced cats, rats, and dogs.
The tortoises especially have a rough time because they compete with goats for some prime, delicious cactus. Galapagos National Park Rangers are pretty serious about getting rid of the goats: "Pilots from New Zealand were hired to fly helicopters above the largest island, Isabela, so that gunmen could reach herds of goats with AR-15 rifles and one million rounds of ammunition imported from the United States."
Anyway, I liked this article because it's an example of evolution getting short circuited by the global transport of all kinds of species; biodiversity loss is a big deal. But I think that the article makes a pretty valuable point: though the goats have a huge impact on the environment of the Galapagos, the rapidly growing human population on the islands will almost certainly have a bigger effect.