Sunlight Affects Life Cycles

Sunlight Affects Life Cycles

One of the wonders of life on planet Earth is the influence of sunlight. As winter fades away and summer approaches, we see all kinds of changes in life. As scientific research continues into the wonders of the animal and plant kingdoms, we see more carefully designed biological systems. Here are some examples of how sunlight affects life cycles:

COCCOLITHOPHORES: These are tiny phytoplankton plants that live in the ocean. As the season changes and the Sun warms the waters, those organisms increase their rate of reproduction. They would smother themselves with overcrowding except for the fact that they give off dimethyl sulfide. That chemical rises into the atmosphere and oxidizes into solid sulfate particles. For raindrops to form, there must be moisture, cool temperatures, and condensation nuclei. The solid sulfate particles provide the condensation nuclei, and the rising air cools the moisture from the sea resulting in clouds. The clouds block the sunlight, thus cooling the sea and slowing down the reproduction rate of the coccolithophores and avoiding a massive die-off. This phytoplankton literally manipulates the weather to ensure its own survival.

SALMON. These fish know when to return to the waters of their birth to spawn. Built into their bodies is a pineal gland that stimulates the pituitary gland, triggering an urge to spawn. Navigation tools designed into the salmon allow them to find the place of their origin where they spawn and die.

BEAN APHIDS AND OTHER ANIMALS. Bean aphids give birth when the length of the day reaches 14 hours and 55 minutes, assuring that the offspring will have warmth. Similar triggers by sunlight affects life cycles, allowing muskox to shed their insular undercoat, mallard ducks to shed their winter down, and snowshoe hares to change their color from white to brown before all the snow melts.

FROM FRUITFLIES TO HUMANS. Fruitflies shed their pupal husk an hour before dawn even when kept in the dark. Even when kept in total darkness, hummingbirds slip into torpor at dusk, allowing them to conserve energy. A poppy folds its petals at dusk, even in a dark box. Both the hummingbird and the poppy will resume operations at dawn, even in the darkness. Scientists are still researching what triggers these changes even without sunlight. Medical researchers are also studying how humans respond to a lack of sunlight, causing seasonal affective disorders (SAD).

Studying the incredible ways in which sunlight affects life cycles on Earth is a great way to grow in appreciation for the creation process. We marvel at the careful design built into all living things. David looked at himself and his world and remarked, “I will praise you, for I am fearfully and wonderfully made: marvelous are your works…” (Psalms 139:14).

John N. Clayton © 2020

These examples were found in National Wildlife magazine Volume 32 # 1.

Half-Slumber Design in Animals

Half-Slumber Design in AnimalsWe have a clock in our brain that is based on circadian rhythms. The clock is connected to Earth’s rotation, and it provides daily periods of rest and recovery called sleep. Animals have it too, and for many animals, sleep is a dangerous time if there are predators around. Scientists have discovered that many animals, especially marine mammals, have a half-slumber system designed to keep them safe and yet allow them to sleep.

The half-slumber system allows half of the brain to sleep while the other half is awake and able to respond to danger or navigational needs. Studies in dolphins have shown that there are different regions of the brain that work together to allow one side of the brain to function while the other side sleeps. The hypothalamus contains ventrolateral preoptic nuclei that exchange messages between the left and the right sides of the brain. They determine which side sleeps and which side remains alert to danger. This also allows movement of the dolphin’s fins and tails to generate body heat in the coolness of the marine environment. It also allows the animal to surface, to breath, and to swim with its companions.

Northern fur seals have a similar system but highly modified. The fur seals come out on land and assume a posture that allows them to put one flipper in the water which they paddle with while keeping the other three flippers in the air to avoid heat loss. Their nostrils are out of the water, allowing breathing and one eye is open and looking for predators. The part of the seal’s brain that provides vision is not connected to the other functions of breathing or movement.

Birds also use the half-slumber design. Mallard ducks have a unique system where the ducks form a group. Ducks on the outside of the group have one eye open, and their brains function differently than ducks at the center of the group. Migrating birds that fly for very long times also use the half-slumber design with one eye and one side of the brain watching where the bird is going while the other side of the brain slumbers. Great frigate birds fly for ten days at a time using this system. Swainson’s thrush gets its sleep by taking micro naps when it is perched.

It seems that every creature using the half-slumber design to get its required sleep uses it differently. The changes are not small and are highly complex involving many organs. Intricate design differences in the brain primarily direct them. Studies of animal sleep are in an early stage, but the complexity of the system is undeniable. The Bible tells us that we can “know there is a God through the things He has made” (Romans 1:18-20). It is a very difficult challenge to understand just how complicated God’s design is. Even in our sleep, we demonstrate God’s plans and engineering.
— John N. Clayton © 2019