Final answer:
Convergent evolution occurs when unrelated species develop similar traits due to similar environmental pressures, like wing development in insects and birds, while parallel evolution involves closely related species evolving alike. Examples of convergent evolution, such as adaptations in arctic mammals and birds for swimming and camouflage, support the theory of evolution by natural selection.
Step-by-step explanation:
Differences Between Parallel and Convergent Evolution:
The main difference between parallel and convergent evolution is that parallel evolution occurs when closely related species evolve in similar ways, while convergent evolution happens when unrelated species develop similar traits in response to similar environmental pressures. For example, the wings of insects and bats illustrate convergent evolution, as they have developed independently in these groups for the function of flying despite no common ancestral structure for wings. Alternatively, parallel evolution would involve species that share a more recent common ancestor developing similar adaptations or features.
Examples of Convergent Evolution:
An example of convergent evolution is the adaptation for swimming found in Arctic beluga whales and Antarctic right whales. These mammals have developed similar body shapes and features for swimming despite living in different hemispheres and not sharing a recent common ancestor. Another instance is the evolution of camouflage, such as the temporary white coverings of the arctic fox and the ptarmigan bird, which help them blend with their snowy environments for survival. These cases support the theory of evolution by natural selection because they demonstrate how similar environmental challenges can lead to the development of comparable adaptations in different species.
Explaining Evolution Through Structural Differences:
Convergent evolution also reveals how entirely different original structures can be adapted to perform the same function. For instance, the ability to fly has independently arisen in insects with their exoskeletal wings and birds with their feathered wings. Furthermore, the idea of evolution is supported by the presence of homologous and vestigial structures, which indicate common ancestry and changes over time, respectively.