Common ancestry can be demonstrated via
A bone homology.
B embryological homology.
C molecular homology.
D the presence of vestigial structures.
E all of the above.
The correct answer and explanation is:
The correct answer is E. all of the above.
Common ancestry refers to the idea that different species share a common ancestor and exhibit similarities due to their evolutionary relationships. Various types of homologies provide evidence for common ancestry, including:
A. Bone homology: This refers to the similarity in the structure of bones across different species. For example, the forelimbs of humans, bats, and whales share a similar bone structure despite differing functions. This indicates that these species inherited a common skeletal structure from a shared ancestor, even though the limbs have adapted to different environments and purposes.
B. Embryological homology: The similarities in the early developmental stages of organisms also suggest a common origin. For example, vertebrate embryos (including humans, chickens, and fish) exhibit similar structures like pharyngeal arches and a tail during certain developmental stages, pointing to a shared ancestry despite the differences in their adult forms.
C. Molecular homology: At the molecular level, similarities in DNA, RNA, and protein sequences can also demonstrate common ancestry. For example, humans and chimpanzees share over 98% of their DNA sequence, which strongly suggests they share a common ancestor. Similarities in the genetic code across different species highlight the evolutionary connections between them.
D. The presence of vestigial structures: Vestigial structures are remnants of organs or features that once had a functional role in an ancestral species but have lost their original function over time. Examples include the human appendix and the pelvic bones in whales. These structures provide evidence that species have evolved from ancestors where these traits were once useful.
Taken together, bone homology, embryological homology, molecular homology, and vestigial structures all support the theory of common ancestry, as they demonstrate that different species share inherited characteristics due to their evolutionary history.