Bones in different vertebrates are if they have the same evolutionary origin but now differ in structure and function.

The bones in different vertebrates that share the same evolutionary origin but differ in structure and function are referred to as homologous structures. This concept is a key idea in evolutionary biology that demonstrates how organisms can evolve from a common ancestor while adapting to different environments and modes of life.

1. Common Origin: Homologous structures arise from a shared evolutionary background, which means that these bones originated from the same ancestral structure in early vertebrates. This shared ancestry highlights the relationships among different species.

2. Divergent Evolution: Over time, as species adapted to diverse environments, these homologous structures have undergone changes. This process is known as divergent evolution, where the structures adapt to fulfill different functions, leading to variations in form and structure. For example, the forelimbs of mammals like humans, whales, and bats are homologous because they evolved from a common vertebrate ancestor, yet they serve different purposes such as grasping, swimming, and flying respectively.

3. Functional Adaptation: The differences in structure enable each limb to perform optimally in its specific environment. For instance, the presence of flippers in whales and wings in bats exemplifies how similar anatomical structures can develop distinct functions that reflect the adaptations of the creatures to their respective habitats.

Understanding homologous structures provides insight into the evolutionary processes that shape biodiversity, illustrating how organisms can exhibit both unity and diversity in their anatomical features.