Which of the following is an example of descent with modification?
The Correct Answer and Explanation is:
Descent with modification is a key concept in evolutionary biology that refers to the process by which species evolve over time, with changes passed down from one generation to the next. An example of descent with modification is the evolution of the horse from its ancestral species.
Correct Answer: The evolution of the horse from its ancestral species.
Explanation:
The concept of descent with modification suggests that all living organisms share a common ancestry but have evolved over time due to various environmental pressures and adaptations. The horse is an excellent illustration of this concept, tracing its lineage back to smaller, multi-toed ancestors known as Eohippus, which lived approximately 50 million years ago.
Initially, Eohippus was about the size of a small dog and had four toes on each front foot and three on each back foot, adapted for living in forested environments. As the environment changed and grasslands expanded, these ancestors faced different survival challenges. Over millions of years, natural selection favored traits that enhanced mobility and speed, leading to gradual changes in the structure of the horse’s limbs.
Through modifications, the horse evolved into a larger creature with elongated limbs and a single hoof on each foot, providing better adaptation for running across open terrains. This change in foot structure allowed for greater speed and efficiency in escaping predators and traveling long distances to find food. The size of the horse’s skull also increased, accommodating a larger brain and changes in teeth structure to better graze on grass.
These evolutionary changes demonstrate descent with modification, as each generation of horses shows modifications that enhance survival and reproduction in response to changing environments. This process underscores the importance of adaptation and illustrates how species evolve over time through gradual changes, resulting in the diversity of life we observe today.