Chapter 20, Problem 1Q

Summary Introduction

To review:

The evidence for the toe pad evolution in the populations of Anoles carolinensis on the invaded islands. Also describe the reason for this rapid change in toe pads of A.carolinensis.

Given:

Anoles are the largest and diverse group of lizards found in America. These are important for the ecological and evolutionary studies. The two species A. carolinensis and the A. sagrei compete with each other and are aggressive in nature. The species of Anoles has a strong association of height with the structure of toe pads, which the lizards use to climb. The researchers found that the habitat of the lizards play a vital role in the evolution in the lizards.

When the A. sagrei was introduced on the islands, the changes were observed. The island only had A. carolinensis, so the introduction of A. sagrei was not supported. The researchers then collected samples of each type and raised their offspring in the controlled environment and analyzed the differences on the genetic basis.

Introduction:

The evolution is a process to know the descendants of the organisms. It helps the biologists to know about the ancestors of the organisms. It also helps to determine the gene that flows from generations to generations. Evolutionary changes refer to the changes that occur in the genes of the organisms due to time and place of evolution. As per Darwin, the evolutionary process is the process by which the organisms change over the period of time. Their changes can be heritable, whether it is physical or behavioral traits.

Explanation of Solution

According to the study, it is stated that larger toe pads with more lamellae are present in the species of A. carolinensis in the islands invaded by A. sagrei, compare to the toe pads of the lizards that is present in the islands not invaded by A. sagrei. The A. sagrei was found in islands in 1995. The difference in the foot structure is seen only since then. The toe pads have evolved very quickly over the period of time. The reasons for the same is, the selection of the larger toe pads with more lamellae in lizards was very strong on the invaded islands.

Conclusion

So, it can be concluded that the evidence for the evolution of the toe pads in the populations of A. carolinensis was the presence of the A. sagrei and the reason for rapid evolution was the selection of the toe pads with more lamellae was very strong.