Los Islotes and Isla Espiritu Santo
Two terms were bandied about during our Zodiac adventures this morning and our walks this afternoon that you just don’t hear every day. They are scientific phrases that point to the fascinating evolutionary adaptations of the California sea lion, one of the marine mammals found in abundance in the Gulf of California¬, and the cardon cactus, a species that dominates the landscape in many parts of the peninsula and on some of the 900 islands in the Gulf.
The first term, thigmotaxis, refers to the preference among California sea lions to be touching one another most of the time. This tendency was plainly obvious to all as we drifted slowly around the many animals lounging, nursing, sleeping and climbing over the rocks that make up Los Islotes. While there were some individuals on their own, most were in pairs, piles and bunches. They lay on top of each other and hauled their bulk rather ungracefully directly over their mates to get where they were going. But why? What is the advantage to this tendency? While there are other benefits, such as providing warmth and comfort, perhaps the most significant relates to the concept of safety in numbers. Just as fish school and ungulates form herds to protect themselves from predators, the practice of grouping up for safety applies to sea lions as well—at least in evolutionary history. Sea lions are believed to have evolved from land mammals, and as such, were food for other land creatures. While predation on land is less of concern at this stage, their genes still tell them to huddle-up for safety.
The second term explains one of the ways cacti have adapted to life in a harshly arid environment. Crassulacean Acid Metabolism, or CAM, basically refers to the way in which gases are exchanged between the plant and the atmosphere for the purpose of photosynthesis. The cardon and other species use nocturnal CAM to reduce the amount of moisture lost to the environment during the process of making sunlight into energy. This is just one of numerous strategies for keeping what little water is available to these stalwart desert sentinels. Other adaptations include the evolution of leaves into spines, expandable pleats capable of storing large amounts of liquid and a thick waxy cuticle that serves as a barrier to transpiration.
The complexity of this world, so wonderfully made, is an inspiration to the artist, a thrill to the scientist and a joy to the heart of all who care to see.
Two terms were bandied about during our Zodiac adventures this morning and our walks this afternoon that you just don’t hear every day. They are scientific phrases that point to the fascinating evolutionary adaptations of the California sea lion, one of the marine mammals found in abundance in the Gulf of California¬, and the cardon cactus, a species that dominates the landscape in many parts of the peninsula and on some of the 900 islands in the Gulf.
The first term, thigmotaxis, refers to the preference among California sea lions to be touching one another most of the time. This tendency was plainly obvious to all as we drifted slowly around the many animals lounging, nursing, sleeping and climbing over the rocks that make up Los Islotes. While there were some individuals on their own, most were in pairs, piles and bunches. They lay on top of each other and hauled their bulk rather ungracefully directly over their mates to get where they were going. But why? What is the advantage to this tendency? While there are other benefits, such as providing warmth and comfort, perhaps the most significant relates to the concept of safety in numbers. Just as fish school and ungulates form herds to protect themselves from predators, the practice of grouping up for safety applies to sea lions as well—at least in evolutionary history. Sea lions are believed to have evolved from land mammals, and as such, were food for other land creatures. While predation on land is less of concern at this stage, their genes still tell them to huddle-up for safety.
The second term explains one of the ways cacti have adapted to life in a harshly arid environment. Crassulacean Acid Metabolism, or CAM, basically refers to the way in which gases are exchanged between the plant and the atmosphere for the purpose of photosynthesis. The cardon and other species use nocturnal CAM to reduce the amount of moisture lost to the environment during the process of making sunlight into energy. This is just one of numerous strategies for keeping what little water is available to these stalwart desert sentinels. Other adaptations include the evolution of leaves into spines, expandable pleats capable of storing large amounts of liquid and a thick waxy cuticle that serves as a barrier to transpiration.
The complexity of this world, so wonderfully made, is an inspiration to the artist, a thrill to the scientist and a joy to the heart of all who care to see.
