READ: Evidence for Evolution
6. Vestigal Structures
Vestigial Structures
Millions of species of animals, plants and microorganisms are alive today. Even though two different species may not look similar, they may have similar internal structures, and chemical processes that indicate they can have a common ancestor.
Some of the most interesting kinds of evidence for evolution are body parts that have lost their use through evolution. Most birds need their wings to fly. But the wings on an ostrich have lost their original use. These are called vestigial structures. Penguins do not use their wings to fly in the air; however they do use them to "fly" in the water. A whale’s pelvic bones-which were once attached to legs- are also vestigial structures.
Mole rats live under ground where they do not need eyes to find their way around. This mole
The bones in your arms and hands have the same bone pattern as those in the wings, legs, and feet of the animals pictured above. How have the bones adapted for different uses in each animal?
If you look at an x-ray of the bones in your back (called vertebrae), you will see several vertebrae that come under your hips. These are called your coccyx, or tailbone. We do not use these small vertebrae; they are further evidence of our evolution.
CK-12 Foundation, Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/