which phrase best defines the term homologous structures? question 3 options: structures that have the same features structures that had a function in an ancestor but don’t have that function today structures that are so similar that they imply a common ancestor structures that have the exact same features and functions
The Correct Answer and Explanation is :
The phrase that best defines the term homologous structures is:
“Structures that are so similar that they imply a common ancestor.”
Explanation:
Homologous structures are anatomical features in different species that share a common ancestry, even if they serve different functions. This concept is a key component of evolutionary biology and helps illustrate the idea of descent with modification, where species evolve from a common ancestor and adapt their structures over time to fit their environments.
An example of homologous structures can be seen in the forelimbs of various vertebrates, such as humans, whales, and bats. Although these limbs serve different purposes—grasping in humans, swimming in whales, and flying in bats—they all share a similar underlying skeletal structure, including bones like the humerus, radius, and ulna. This similarity indicates that these species diverged from a common ancestor that possessed a similar limb structure.
Contrastingly, analogous structures serve similar functions but do not share a common ancestry. For instance, the wings of insects and birds are analogous; they both enable flight, but their structural differences indicate that they evolved independently in response to similar environmental challenges.
The presence of homologous structures supports the theory of evolution by demonstrating how different species can adapt similar features from a shared ancestor to meet their unique needs. This concept is crucial in understanding evolutionary relationships and the process of natural selection, as it illustrates how evolutionary pressures can shape anatomical structures over time while retaining traces of their ancestral forms. Thus, homologous structures are not only pivotal in the study of anatomy but also serve as vital evidence for the evolutionary connections among diverse life forms.