Activity #8: Kemp’s Ridley Turtles
Humans have always been connected with the ocean. We have harvested its foods and harnessed its power. We have also learned about the vast reservoirs of crude oil that lie beneath the ocean floor. Recovering this oil is not without risk, however. The oil spills in Alaska and the Gulf of Mexico have demonstrated the immediate destruction and long-term consequences that can happen when we remove or transport oil across the ocean. The oil spill in the Gulf has the potential to seriously affect the Kemp’s ridley turtle, the most endangered turtle in the world. It is believed that hundreds of these turtles have died due to the oil spill. It may be true that if the Kemp’s ridley does not adapt to its new oil- and chemical-filled environment, then the species will become extinct. The Kemp’s ridley turtle is uniquely disadvantaged because it nests along gulf beaches in Mexico and south Texas. As soon as the hatchlings come out of the nest, they are driven by instinct to head directly toward the ocean, where they will spend their entire lives. All Kemp’s ridley turtles hatch on gulf beaches and make their first home in the warm waters of the Gulf of Mexico. Now that this water is tainted with oil, these baby turtles face greater peril than usual in the place they are supposed to call home. Oil can damage turtles by burning the mucus membranes of their eyes and mouth. Oil can cause skin irritation and gastric disturbances. Oil can also cause them to have ulcers and develop organ damage. The biggest threat they face, however, comes from breathing in the oil, which can cause emphysema, pneumonia, and death. Although what has happened is tragic, the Kemp’s ridley turtles are not the first species to be threatened by environmental change. Many scientists believe that dinosaurs became extinct because of an environmental change. Environmental changes can be short or long term. For example, a short-term environmental change would be a forest fire. Initially, the environment would be radically different, but in a few hundred years it would be difficult to notice evidence of the fire. A long-term environmental change could be caused by acid rain or global warming. This kind of event causes changes that may be imperceptible to the human eye but eventually devastating. It can be easy for people to ignore or misunderstand the threat of a slow environmental change because the effects are not readily visible. An oil spill causes both short- and long-term changes in the environment. Scientists are still observing effects from the 1989 Exxon Valdez oil spill. Adaptations usually take many generations to occur. That means these are not changes that happen spontaneously because of a rapid environmental change. No Kemp’s ridley turtle that is exposed to oil will consequently develop an adaptation to better protect its offspring from oil. If there are any Kemp’s ridley turtles that happen to have a genetic mutation that allows them to better thrive in an oil-ridden environment, then they will be more likely to survive and pass on that genetic mutation to their offspring. If the oil threat is extremely deadly, then only those Kemp’s ridley turtles with that mutation will continue to survive. Adaptations generally spread through entire populations there will not be one, lone floating Kemp’s ridley turtle who survived because of his genetic mutation. Either a viable population survives, or the species becomes extinct. One or two individuals with mutations cannot save an entire species. Some traits that may be favorable in a warm, oil-ridden environment would not be needed in the clean Arctic Ocean. Even similar species would develop different adaptations in different environments. The ability to easily release extra body heat may be helpful in a desert, but harmful in the Arctic. The camel’s hump, which allows it to store extra water before a trek, is completely unnecessary for a rainforest monkey. Our environment is constantly changing. Fortunately, most of these changes take hundreds or even thousands of years to occur. Recognizing the traits that have survived for hundreds of years helps us to discover that such short- and long-term environmental changes are powerful, dynamic forces that have literally shaped the world we live in today.