Which of the following is NOT an example of unity?
A Similarity in cell structures
B the presence of vestigial, or useless traits
C different modes of replication in prokaryotes and eukaryotes
D common embryonic stages
The correct answer and explanation is:
The correct answer is C) different modes of replication in prokaryotes and eukaryotes.
Explanation:
Unity in biology refers to the common features, traits, or processes shared by all living organisms, reflecting their shared evolutionary origins. Several characteristics demonstrate this unity, including similar cell structures, common embryonic stages, and vestigial traits, which are all evidence of common ancestry.
A) Similarity in cell structures: All living organisms, whether prokaryotes or eukaryotes, share basic cell structures like membranes, ribosomes, and DNA. Even though eukaryotic cells are more complex, they still retain these fundamental components, showing unity in the basic building blocks of life.
B) The presence of vestigial traits: Vestigial traits are structures or behaviors that have lost their original function through evolution. Examples include the human appendix or the pelvic bones in whales. These traits are inherited from ancestors and show how species have evolved over time, sharing a common evolutionary path.
D) Common embryonic stages: Many species, especially vertebrates, go through similar embryonic stages. For example, during early development, embryos of humans, fish, and chickens all have similar features like pharyngeal arches and tail-like structures. This reflects a common ancestry and further supports the idea of unity among living organisms.
On the other hand, C) different modes of replication in prokaryotes and eukaryotes is not an example of unity. While both prokaryotic and eukaryotic cells replicate DNA, the processes differ significantly. Prokaryotes generally replicate through binary fission, a simpler and faster process, while eukaryotes undergo mitosis or meiosis, more complex processes with additional regulation. These differences highlight the evolutionary divergence between prokaryotes and eukaryotes, rather than unity. Thus, the different modes of replication point to the distinct evolutionary paths of these two groups of organisms.