To keep a balance among living things in the natural world, there have to be many ways for animals to get food. In lakes, oceans, and rivers this is especially difficult because of the amount of cover that exists in which small fish can hide. If small fish over-populate, they exceed their food supply and the whole ecosystem collapses. One way to keep balance is with a predator that is an electrogenic fish.
One of the agents designed into the ecological system is the existence of living things that send out electrical charges. Very little is understood about how this works, but new data is enabling us to understand how cleverly electrogenic fish are designed to enable them to find and eat forage fish.
The January/February 2018 issue of Popular Science (page 75) has an interesting article by Ken Catania, a professor of neurobiology at Vanderbilt University on his studies of electric eels. What he found is that when an electric eel discharges a high-voltage pulse, the nerve fibers in nearby animals are affected. If a small fish is swimming near the eel, it becomes frozen like a statue long enough for the eel to catch it. Even more interesting is the fact that the eel can make any creature that is nearby twitch when the eel fires off a blip of current. The eel can swim up to a clump of seaweed and fire off a pulse. Anything hiding in the seaweed, like a small fish, will reveal its presence by twitching.
Scientists have difficulty finding information about dinosaurs. Much of what we know about them has come from indirect information. I spent a great deal of time studying coprolite, which is petrified dinosaur droppings. By analyzing the solid wastes left by a dinosaur, we can tell what the animal ate. Sometimes we find plant materials–leaves, stems, seeds, etc. Sometimes it’s animal remains–teeth, bone fragments, and complete bones. It is extraordinarily rare to find a complete skeleton of a dinosaur, but now we have something even better.
Until recently we had never found an animal with skin in place and internal organs visible. In 2011 miners working in northern Alberta came across an amazing find that has given scientists their first complete mummy of a dinosaur. This dinosaur was a plant-eating nodosaurus, which means “knobbed lizard.” This animal is complete with its armor, spiky skin, and internal organs. Paleontologists have spent some 7,000 hours carefully extracting the creature. Caleb Brown, who is a researcher on the project, said, “We don’t just have a skeleton, we have a dinosaur as it would have been.”
Dinosaurs were the agents that prepared Earth for humans. Without that preparation, we would not be able to have our crops, our domesticated animals, and our advanced civilization. Dinos were key agents in preparing an ecosystem suitable for us. They lived in an environment very unlike what we have on Earth today. Having a find like this will greatly enhance our understanding of Earth’s history.
One of the most interesting examples of design in living things is the ability that various forms of life have to migrate great distances for a wide variety of reasons. Sea turtles have an uncanny ability to return to the same beaches over and over to lay their eggs. Whales can travel long distances when they are ready to calve, giving their offspring a greater chance of survival. Migrations can be critical to animals or plants other than the animal making the migration. Sometimes the migration is critical to an environmental ecosystem. The salmon migration in Alaska, for example, is critical to the entire area sustaining plant life and a wide variety of animal life.
When insect migrations are studied, the question of how they make the migrations and why becomes even more complicated. Monarch butterflies make migrations of great lengths even though their life expectancy is too short for any single butterfly to make the entire migration. The champion of insect migrations is the globe skimmer dragonfly (Pantala flavescens). This insect has wide wings that look very delicate, but those wings can carry it for thousands of miles seeking wet seasons when it can reproduce. Migration has spread this insect’s DNA worldwide to every continent except Antarctica. Globe skimmers can fly for hours without landing and have been seen as high as 20,000 feet (6,200 m) in the Himalayas. They are sometimes called wandering gliders because they can glide on thermals in a way similar to birds. They seem to prefer moist winds, and they don’t stop for bad weather.