10 Adaptations-Mid

Adaptations Written by Ron Fridell

Introduction Afternoon sunlight spills through the trees in a city park. A small bird called a warbler sits on a tree branch, singing a beautiful song. Suddenly he stops and dives to catch an insect flying by. The insect struggles, but it can't escape. The warbler returns to his branch to enjoy his snack. Down on the ground, a bright red cardinal cracks open seeds with his hard bill. A quick, hard rat-tat-tat-tat sound splits the air. Splinters fly as a woodpecker drives her hard, chisel-like beak into a tree. Hunting grubs, she drills through the bark like a jackhammer. On a pond nearby, some ducks float slowly along. Their heads dip down into the water and back up, their wide bills dripping with water.

These birds are all looking for a meal. But because their food is different, their beaks have different shapes. The warbler's beak is thin and pointed, like tweezers, to catch insects. The cardinal's beak is short and hard for cracking seeds. The woodpecker uses its long, strong beak to dig into wood. Ducks have wide bills for straining plants and fish out of the water. Over hundreds of thousands of years, these birds beaks changed to help them gather the food they need. All plant and animal species have adaptations, or changes that help them survive in their habitat. Why do certain adaptations develop? And how do they help each plant or animal? Let's find out.

Survival of the Fittest Species adapt to changes in their environment in order to survive. How do adaptations happen? A species is made up of individual organisms. Individuals within a species are born with slight differences, called mutations. Sometimes, mutations change the traits and behaviors of living things. Some individuals have traits and behaviors that help them live in a certain environment. These individuals are able to survive and reproduce. Then those helpful features are passed on to offspring in the next generation. Individuals that do not have these traits and behaviors may not survive. As a result, they do not reproduce. Over time, more and more organisms are born with the features that help them survive. These features become adaptations for the species. The first person to write about this idea, often referred to as survival of the fittest, was Charles Darwin, a British naturalist. He wrote a book called On the Origin of Species by Means of Natural Selection. It was published in 1859.

Let's consider an example of one adaptation and how it happened. Millions of years ago, all whales had teeth and breathed out of holes at the end of their snouts. Over many generations some whales developed a breathing hole farther up their head. These whales could breathe more easily in deep water. They could rise to the water's surface and take a breath without sticking their snouts above the water. As whales began to spend more time far out in the ocean, away from shore, more whales with higher breathing holes survived. Their babies also had breathing holes high on their heads.

Today, a whale's nose, called a blowhole, is on top of its head. The blowhole is an adaptation that makes it much easier for the whale to breathe. The whale could not breathe as well if it still had the nose it had millions of years ago. A whale takes breath with its blowhole above water. With its lungs full of air, the whale lifts its tail and dives back down into the ocean.