The Circle of Life II

Animals have strong survival instincts. An instinct is a behavior with which an animal is born. For example, from birth, a puppy instinctively knows to suck milk from its mother. Instincts help animals find food, mate, reproduce, and raise their young. Survival instincts also lead animals to migrate or move to a better habitat. Some animals migrate only short distances. Others, like the wildebeest on the African Serengeti, are continually migrating great distances. Why do they migrate? To find better living conditions.

Instead of migrating, some animals instinctively protect themselves from changes in living conditions through hibernation. In seasonal habitats, some animals survive the winter by going into deep sleep during which the animal lives off of its stored fat and uses very little energy. This way, the scarcity of sunlight, food, and warmth don't risk the animal's survival. Bears are certainly the best known hibernators, but not the only.

Living things continually face threats to their survival and life cycle. Sometimes, the threats are natural and uncontrollable, like sudden changes in climate. For example, plants can be threatened by an unexpected drop in temperature. Sometimes, however, the threats are unnatural, manmade, and controllable. Pesticides, for example, threaten the survival of insects that feed on plants. However, animals that also feed on the plants can be threatened by the pesticide too. Yet, the animals need to be able to eat the plants. So, how to control the insects, protect the plants, and feed the animals all at once? Nematodes are one possibility. The nematode is a parasite that feeds on the insect without hurting the plant.
Picture of yellow nematode

Survival is a daily challenge for all living things. Meanwhile, other concerns also must be addressed. Plants and animals reproduce at different stages of their life cycle and in different ways. Flowers, for example, have both male and female reproductive organs. The male organ, called the stamen produces pollen which, through pollination, gets moved and attached to the sticky pistil. The pollen then grows down into the pistil until it reaches the ovary which houses and protects the ovule. Once the male pollen cells join with female cells, fertilization occurs. The fertilized embryo grows into a seed that can grow into a new plant.

Many flowers require cross-pollination. The pollen from the stamen of one blossom is intended to fertilize the ovule of another blossom. If two tulips are growing side by side, the pollen from the first tulip should attach to the pistil of the second tulip. How? Most often the wind or insects transport the pollen from flower to flower. The bee is the best equipped agent of fertilization for the flower. The attractive color, scent, and flavor of a flower draw the bee to the pistil where it "drinks" the flower's juices. As the bee flies away, it touches the stamen, picks up some pollen, and carries it to another flower's pistil. This mutually beneficial relationship is known as symbiosis.

For plants, reproduction is often the final stage of maturity. Death is the end of the plant's life cycle. Some animals also die right after they reproduce. Other animals, however, have an extended period of aging following reproduction. Eventually, however, all living things conclude their natural life cycle.