Sometimes, we can overlook design features in living things even though they are all around us. Most of us who have had tropical fish aquariums are familiar with the fish known as neon tetras. These fish are great for aquariums because they are tiny – usually about an inch long. They have a brilliant blue stripe running laterally and a red strip underneath toward the tail. These fish are native to the Amazon Basin and live in freshwater.
Researchers have discovered that neon tetras have a quality lacking among many humans. They have the ability to wait their turn. Researchers took a school of tetras and put them in a tank that had a narrow opening to get to a food source. The tetras could get through the narrow opening without clogging and impeding passage. The small fish didn’t collide with one another as they swam through the opening to get to the other side of the tank. Researchers say ants are the only other form of life to demonstrate agility in avoiding bottlenecks.
One has to wonder why these fish have this ability since humans have not solved the problem of getting large numbers of people through narrow openings. Neon tetras live in streams that pass through many rocks, and being able to wait their turn gives them a better chance of survival than if they ended up with a bottleneck.
All living things have characteristics carefully fitted to their needs and environment. As we study life forms, we see this repeatedly, and it screams out the message of Romans 1:20: “we can know there is a God through the things He has made.”
One of the frustrating parts of the world situation today is the waste of food. Nearly every day, we get letters from relief organizations about hunger and pictures of starving children. The fact is that God has given us a planet that produces more food than we humans can eat. Food shortages and starvation result from mismanagement and failure to use all that God has given us.
The World Resources Institute tells us that 35% of the food produced in North America goes to waste. Most of this waste occurs at the consumption level in our homes and restaurants.
Some farming practices also contribute to the waste problem. In our area, people grow watermelons. When harvest time comes, hundreds of melons are left in the field to rot. The problem is that what sells at the market is melons of a specific size and weight, so melons that don’t meet those criteria are left in the field. Green beans are grown here, and the machines that harvest the beans cut off the plants allowing only one harvest. If allowed to continue to grow, the plants would produce many more beans.
In most animal species, the female is the one who gives birth and cares for the young, but that is not always the case. One exception to that rule is the seahorse role reversal.
Females seahorses compete to secure a mate. The female is the leader in the courtship ritual, which involves an extended “dance.” After the ritual, the female will deposit her eggs in a pouch on the front of the male. The male fertilizes the eggs and keeps the embryo sea horses for as long as ten weeks.
At the end of that time, the male ejects the young with muscle contractions, pushing them out into the ocean to fend for themselves. There can be dozens or hundreds of tiny seahorses, depending on how big the male is. Sea horses live in dense seaweed, which supplies food and hides them from predators. Small fish such as seahorses are easy prey for many animals in the sea, so they need to reproduce in large numbers.
Besides the seahorse role reversal, there are other cases in the natural world where a male is the caregiver for offspring. Diversity is the answer to many needs of a balanced life system, and the male and female roles can be different depending on the needs of the ecosystem.
The more we learn of the natural world, the more examples we see of incredible design and planning which reflect God’s actions in preparing this planet for human life. We all have a role in protecting the diversity of living things God has placed in our care.
The American paddlefish is an interesting but relatively unknown fish species. These fish have large paddle-shaped appendages on their foreheads, and they inhabit the murky waters of the Mississippi River and its tributaries. They can grow to six feet (183 cm) and weigh 150 pounds (68 kg). So what is the purpose of the paddle? The electroreceptors of paddlefish answer that question.
You might think that the paddle is a device to dislodge food from river bottoms. Some people called them “shovelnose fish,” assuming they used their paddles as a shovel. But paddlefish don’t dig for food, and lab experiments in 1993 showed the paddle’s real purpose.
Paddlefish are filter feeders that feed on tiny crustaceans and insect larvae that drift through the water as plankton. Many whale species are filter feeders that use comb-like baleen in their mouths to strain their food from the water. Paddlefish have comb-like rakers in their gills. They swim with their mouths open and filter their food from the water. But that doesn’t explain the paddle.
Paddlefish have poor eyesight and no sense of smell, so how do they know where to swim to find food? The paddle is covered with tens of thousands of electroreceptors that can sense extremely minute electric fields. Plankton emit signals that are similar to what doctors measure in electrocardiograms. Paddlefish use their electroreceptors to detect those signals and locate the plankton, even in murky waters.
The electroreceptors of paddlefish are similar to those of the platypus found in Australia. Many marine fish, including sharks, skates, rays, and some freshwater fish, can use weak electrical signals for feeding and communication. Those fish don’t need light or clear water to eat and maintain a balance in the environment. This ability is not something that evolved in the paddlefish because fossil evidence seems to indicate that they had electrosense ability very early in Earth’s history. We are amazed by God’s designs that we see in living things.
An amazing fact is that the creation is designed for continually spreading life throughout the Earth. That isn’t always a good thing for humans.
Several years ago, a friend of mine built a large pond on his farm. He planned to stock the pond with desirable fish, avoiding carp and sunfish, which he considered to be trash fish. He stocked it with largemouth bass, and some minnows used as food for the bass. Later, when I was visiting him, I decided to do a little fishing in his pond. The first fish I caught was a large carp, and a whole school of sunfish converged on a grasshopper or worm I used as bait.
My friend was horrified and promptly wanted to accuse an enemy of putting trash fish in his pond. I noticed a great blue heron wading through the shallows of the pond picking off minnows, and immediately I knew how the sunfish got there. Herons wade through areas where fish have built nests of eggs during their spawn. The eggs are sticky and adhere to the Heron’s legs. When the Heron goes to another pond, it carries the fish eggs along.
Recent research has discovered another way in which fish are designed to spread from place to place. A study in Hungary has shown that some fish eggs can pass through the digestive system of a duck, and a small percentage of the eggs have baby fish still alive inside.
The wisdom of this system in the natural world is apparent. A new body of water will usually be sterile. To get a functional ecological system going, the bottom of the food chain must be established quickly. Birds are facilitators in getting a fish population in operation, and now we know of at least two ways they do it.
The implications for humans are significant. Biologists trying to keep a species of carp out of the Great Lakes have a huge problem. The design of fish and birds makes it almost impossible to keep any fish population isolated. God has created many designs for spreading life throughout the Earth, even into sterile places.
Biologists are always finding and studying new life-forms. Among recent discoveries are fish as flat as a pancake.
How many species of biological life exist? So far, scientists have identified, classified, and named about two million. They estimate that there are somewhere between ten-million and one-hundred-million. How fast are scientists finding and describing new forms of life? About 18,000 new species are identified and given genus and species names each year. At that rate, it will take somewhere between 555 and 5,555 years to identify them all. Obviously, biologists have a lot of work left to do.
Each year, scientists identify most of the “new species” from museum specimens that were found earlier but not studied carefully. Some species in the wild are going extinct, and some of the museum specimens may already have gone out of existence. Two species that are not endangered and that were discovered in the wild in 2010 are fish “as flat as a pancake.”
Scientists discovered two species of pancake batfish in the Gulf of Mexico near the Deepwater Horizon oil spill. They gave their discoveries the genus and species names Halieutichthys intermedius and Halieutichthys bispinosus. (The picture shows the similar Halieutichthys aculeatus.) You probably won’t remember their names (or even know to pronounce them), but they play a role in the balance of life in the ocean.
Pancake batfish live on the sandy bottom of the ocean between 148 and 2,690 feet (45-820 m) below the surface. They are flat, that’s why the name “pancake,” and they cover themselves with sand to wait for prey. They eat snails, worms, clams, scallops, and other crustaceans. Their maximum diameter is about 4 inches (10 cm), and they move over the ocean floor by hopping on their fins.
We have to wonder why there are so many species.God created living things with the ability to adapt to many environments, with each one filling a niche in the marvelous system that makes our lives possible. He even gave us strange fish as flat as a pancake. Furthermore, God created us with unquenchable curiosity and plenty of things to study. We believe that we can learn more about God as we explore the creation.
Many years ago, while working in a teen camp in Alaska, I heard a skeptical teenager disparage God’s existence by saying that if God existed, He certainly wouldn’t have made mosquitoes. I have heard similar comments about ticks, hornets, lice, locusts, spiders, and stink bugs. I suspect we have all had times when we were unhappy with annoying bugs, yet when you examine the role of insects, you realize they are critical to our own existence. The well-known entomologist E. O. Wilson said, “If human beings disappeared tomorrow, the world would go on with little change, but if invertebrates were to disappear, I doubt the human species could last more than a few months.” Why do we need insects?
Insects pollinate plants, aerate and fertilize the soil, decompose dung, and the bodies of things that have died. They control pests contributing 70 billion dollars every year to our national economy. Ninety-six percent of land-dwelling birds feed their young on insects, consuming approximately 400 to 500 million tons of insects. Most creatures in and around lakes and streams feed on insects, including fish and bears.
Why do we need insects? Humans are already seeing the cost of eradicating them. There are 68 species of bumblebees and roughly a fourth of those are in danger of becoming extinct. In Europe, the data shows a 76% drop in insects, including bees, beetles, lacewings, and katydids. The loss of pollinating insects has sharply affected the growing of many cash crops, and scientists are studying the effects of insecticide use.
Before we castigate God for what He has created, we need to be sure we have all the facts. We should learn what each creature does and how it contributes to our own well being. I dislike mosquitoes as much as the next person, but a majority of mosquitoes are pollinating insects. I am reactive to a bee sting, but bees contribute to much of what I eat. From our earliest existence, God has challenged us to take care of what He created. (See Genesis 2:15.) That includes caring for and protecting the agents that allow Earth to be hospitable to our existence.
Yesterday we discussed how fish drink water. In the ocean, the problem isn’t water but salt. Ocean fish are designed with specialized gills that support the kidneys in getting rid of salt accumulations that would otherwise pickle the fish. Obviously, not all animals that live in the ocean have gills. How do sea animals drink water?
Albatrosses and petrels are birds that can spend a year or more in the open ocean, but they need to drink water. Whales and seals also do not have land-based water supplies, and yet, like all mammals, they need water to survive. So how do sea animals drink water when ocean water is salty? God’s design of living creatures always includes unusual equipment to enable them to deal with their environment.
In the case of sea birds, they have a set of salt glands in their heads that connect to the bird’s nostrils. The birds drink seawater, but the glands are so efficient that within three hours, all of the salt is removed through the nostrils.
Whales and other aquatic mammals produce urine that has extremely concentrated salt content. By allowing high salt concentrations in the urine to diffuse into the ocean, the salt never reaches toxic levels inside the animal. An interesting sidelight to this is that the milk of these sea mammals is very low in water content. In that way, they conserve water. Milk from seals has only half the water content of lean hamburger.
Everywhere we look in the natural world, we see that a wonder-working hand has gone before. These marvelous designs are not the product of mindless chance. They show an Intelligence who created with purpose and wisdom. When we realize that ocean water has high salt content, we question, “how do sea animals drink water?” God already took care of that.
In Job 38-40, God challenged Job to advance his understanding of God’s power and wisdom by considering the natural things of creation. When Job questioned God’s wisdom and purpose in his personal struggles, he did not recognize the wisdom shown in creation’s design. We too need to look at what God has done and “know there is a God through the things He has made” (Romans 1:18-20).
Have you ever wondered how a fish drinks water? Your first reaction is probably something like, “It opens its mouth.” Like most things in life, it isn’t that simple.
All living things necessarily have some saltwater content in their bodies to keep chemical balance allowing life to exist. The fluids inside an ocean-dwelling fish are only about a third as salty as the ocean itself. The water inside the fish’s body tends to leave by osmotic pressure, which is the tendency of fluids to move through membranes toward higher concentrations. To avoid this loss of water, the fish does simply open its mouth and drink seawater. But that brings large amounts of salt into the fish’s body. The salt concentration would be more than the fish’s kidneys could handle. To aid the kidneys, the gills of ocean fish are designed to expel salt, so the fish isn’t pickled by it.
In freshwater fish, the osmotic pressure is reversed, so the fluids inside the fish are saltier than the water outside. The skin of a freshwater fish is designed so that water seeps in through its skin and gills. Therefore, the fish doesn’t have to drink at all. When a salmon leaves the ocean and enters a freshwater stream, it merely stops drinking. Like freshwater fish, it depends on its skin to bring in its water needs.
Now that you know how a fish drinks water, the next question would be about other creatures that spend their time in the sea. Birds like albatrosses and petrels can spend more than a year at sea, and whales and seals live in the ocean 24/7/365. How can they avoid being poisoned by the salt? We’ll discuss that tomorrow.
God’s design of life includes fitting living things with specialized equipment to survive in every environment. Fish are remarkable creatures specially equipped for the waterworld in which they live.
Throughout the natural world, we see special design features that allow animals to survive in environments that place unique demands. Chameleons have an eye-brain connection that enables the eyes to rotate independently of one another or work together when needed. Chameleons use their tongues to catch insects, but to capture their food, both eyes must work together to overcome depth perception issues. At the same time, chameleons are very vulnerable to predators, so their eyes must rotate independently to look in several directions at once. We find another example of unusual eyes in the genus of four-eyed fish, Anableps.
Anableps live in northern South America and Trinidad, where they swim in the surface waters of lakes and rivers. Near the surface, they are easy prey for birds, so they need to see above and below the water simultaneously. They appear to have four eyes, two above the water surface, and two below the surface. In reality, they are not separate eyes. The eyes are divided into two sections, separated by a band of tissue.
Each section of the Anableps eyes has two corneas, two pupils, a single egg-shaped lens, and one retina that is also divided. The portion of the eyes located above the water connects to a different section of the fish’s brain than the area below the waterline. These four-eyed fish are ideally suited to fill an ecological niche that no other fish can.
You might think that all fish could use this design, but every ecological niche has animals designed to inhabit and maintain that location. Anableps are unique, and that makes them popular aquarium fish. More importantly, this unique design speaks of God’s imaginative creativity in providing full use of every resource on planet Earth with creatures like the four-eyed fish, Anableps.