Question:- Which type of evidence is least likely to result in changes to a phylogenetic tree?
A. DNA sequencing
B. fossil record
C. discovery of new species
D. physical characteristics
Answer: D. physical characteristics
The type of evidence that would not lead to a major change in some phylogenetic trees is the physical characteristics. This is so because the physical attributes that are also termed morphological structures may themselves give quite an opposite message because of the occurrence of what is called convergent evolution or evolutionary plasticity. Though morphological characteristics were previously used to outline the initial phylogenetic trees, they are considered inaccurate as compared to molecular data for categorizing the species.
For instance, dolphins and sharks will be classified under similar types since they both have body shapes and fins in that they might have evolved from the same stock. However, based on this genetic analysis, it will be deciphered that the Dolphin is more related to the cow than the shark notwithstanding the aspect of similarities in physical features being due to adaptation to a similar habitat. Likewise, two objects may share the same physical property such as flight in the case of bats and birds but genetic information distinctively relegates bats as mammals. However, DNA sequencing gives a more exact picture of the proximity of species in terms of relatedness and phylogenetic tree. New ancestors always could be discovered through the analysis of the shape of the fossils and thus modify the previously set temporal scales of the development of species. First, it is useful to know that new species can be identified to complete the existing phylogenetic trees or to form a new branch. Such pieces of evidence seem to be much more likely to produce massive readjustments in phylogenetic trees, compared to those that are physiological traits in the first place, and already well-represented in classifications.
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