Let’s play a little game, shall we? What is the first thing you think of when you hear the word ‘Island?’ Probably you picture a place like Hawaii, or the Bahamas. Long, sandy beaches, palm trees, and probably surrounded by tropical forests. I want to picture yourself walking down the beach on your imaginary, ideal island. As you walk, you hear the soothing crash of the waves on the shore, the call of seagulls as they hunt for fish, and you can hear the gentle rustle of leaves as the wind blows through the palms. It seems to be an average tropical habitat… but then things get weird. As you’re walking along, you suddenly come across the ugliest lizard you have ever seen sunbathing on a rock. It looks like an iguana; however, it has a reddish gray color. As you watch, this lizard scurries down the beach and runs headlong into the surf. Swimming iguanas? What!?! You start your walk again, eyes peeled for any more of these strange lizards, suddenly, you see several small, dark shapes waddle out onto the beach. Taking a closer look, you realize they’re some sort of seabird, (a Cormorant to be exact). However, upon further examination, you realize that the bird’s wings are very short and useless for flying. Again, you are taken aback. What kind of an island is this anyway? Finally, as the birds are headed to the shoreline, you see some more black objects emerge from the surf. At first you think they are more of these strange, flightless cormorants, but to your utter shock, you see a small herd penguin waddling up the beach. Dang, this island is even stranger than my family!
While that was an obviously an odd and (rather stupidly) humorous ‘game, all of the sights and animals that were just described to you are actually found in great abundance on a certain group of islands.
The Galapagos Islands are located some miles off the coast of Ecuador. They are on the western end of South America, smack dab in the middle of the pacific, while still right on the equator. The Galapagos consists of 21 total islands, centering themselves around the main, volcanic island of Fernandina. These islands are best known for the ocean voyage in which the famous “Father of Evolution” Charles Darwin first formed his own version of the theory of evolution.
So, the obvious question is, how did all these random species from completely different habitats make it to the Galapagos? Well, let’s start with the birds, such as the Galapagos Cormorant. A Cormorant is a type of seabird commonly found on the coasts of multiple countries including the US. Although the Galapagos cormorant appears to behave like its mainland relative, there is one key factor that separates the two birds. The mainland cormorant has a set of wings, spanning around three to four feet tip to tip, while the Galapagos cormorant has two small, flightless wings spanning barely a foot wingtip to tip. How could these two birds be so different yet so closely related? Strong wind currents likely blew the cormorants (and the other bird species found on the islands) out to sea; they stumbled across these lush islands; and they decided to made them their home. Scientists believe a similar process happened to the penguins and sea lions.
There are three major currents in and around the islands. One current comes from the far west, one the south, and one the northeast. The southernmost currents would have brought penguins up from their home in Antarctica, while currents from farther north would have flowed down, bringing in any hapless sea lions hunting to far out at sea. Finally, what about the iguanas? The current theory is that these iguanas would climb onto rafts of seaweed and driftwood that would get bunched together. Once these animals got stuck onto these rafts, the currents would guide them straight across the ocean to the island.
Now, let me answer the question that has been going through your head through this entire article. How could these animals can fly one day, then the next not be able to? How can common iguanas become able to swim underwater? The answer is the discussion point of this story, a process called adaptation (or micro-evolution). Most of you have probably heard of this process. Adaptation is the process of change that goes on in a species of animal that allows it to better live and survive in its habitat. Let’s use the Galapagos penguin as an example. Penguins originated in Antarctica. However, northerly current flow brought some of these penguins up from their ice-covered habitat and up to the hot, equatorial climate. Over time, the penguin’s “adapted” to their environment. Slowly, they changed into a different type of penguin built to live in warm climates. Now that we have the basics, let me break it down even more. In your body, there is material called DNA, which is the “blueprint” for you. It can be found in every living thing, from the tree outside to your pet dog. DNA is a very tiny, sophisticated molecule that is found in every one of your cells. If you can remember biology class, you’ll probably remember the structure of cells. While I won’t go much into that here, I’ll go into the parts that have the most to do with DNA.
DNA is stored in the center of the cell, and then is transported out of the cell’s center into the fluid filled cytoplasm. There the DNA strands go into numerous chemical reactions which produce amino acids, which ultimately are used to build cells. Adaptation (or micro-evolution) is the process where genes are altered inside your body just a little bit to allow an organism to thrive in the environment it is in. For example, the genes of the penguin who originated in Antarctica, but was exposed to and settled in a hot, sandy habitat, adapted ever so slightly, turning it into a different type of penguin. The exact processes are in fact, still rather a mystery to scientists. It is the realm of genetics that is one of (if not the most) complex areas of active research in the scientific community.
I have so far mentioned both adaptation and evolution. As I previously mentioned, a famous scientist by the name of Charles Darwin first formed his theory of evolution while at the islands. According to his theory, random mutations and changes in an animal’s DNA can — over a long period of time — change one species of animal into another. Adaptation is also the ability of an animal to change its DNA over time. While these two concepts sound alike, they are actually very different. Evolution requires large, widespread mutations in the genome to work properly. However, these changes do not happen in any certain order and are rather sporadic in their happening. Genetic mutations (while observed in a lab) typically end in DNA strand damage, ultimately harming the organism. Adaptation has been observed to be beneficial and doesn’t require mutations, because it uses information already found in the genome and naturally alters it.
Many species have adapted to live on the Galapagos islands, forming one of the most intriguing habitats in the world. Because of the perfect placement of the islands, it sits right on the middle of three main pacific currents, and has many winds blow in from inland South America, allowing these islands to collect many species that would not be found there under normal circumstances. But due to the unique ability species have to adapt, these species have managed to thrive in this tropical paradise.