Question

Which of the following cannot determine phylogenetic relationships?
A. Physiology
B. Morphology
C. Anatomy
D. Embryology

Answer 1

Phylogenetics stream in biology refers to the study and inference of evolutionary relations shared by different organisms. The phylogenetic relations tell about the evolutionary time shared by two or more species. The species are related to each other based on various factors. The physical appearances may resemble much but phylogenetic relationships can be very different for the same.

Complete answer: The phylogenetic relations are the linkage between the two or more species. Various mathematical models are used to infer the relationships between the different species based on some similarities seen in the species. Some organisms seem to share lots of morphological characters of physical appearances that mislead the scientists to consider them closely related to the phylogenetic tree. But physical characteristics should not be used to infer evolutionary relations among species. The various other factors differ largely as compared to morphological similarities. Thus, genetic makeup, physiology, Anatomy, Embryology, etc are used as standard tools to determine phylogenetic relationships.
-Physiology refers to the functioning of organisms and their parts. Every organism has different functional features that make them different from others. For example, most mammals have four sets of limbs, but humans use two of them to walk and two to write or do other things. But animals like cats, dogs, etc. use all four limbs to walk.
-Morphology refers to the outer appearance or the physical characteristics of the organisms. They can misguide the phylogenetic relations as they seem similar in many organisms that are distantly related. For example, wings in birds seem to be similar but each species of birds differ significantly.
-Anatomy is the internal structuring of the body and body parts in an organism. The anatomy differs largely from species to species and can be used as a basis for inferring phylogenetic relations.
-Embryology is concerned with the observation of the development of embryos in different species. Each species is specialized to have their specific types of reproductive stages and embryological developments. The embryology varies largely from species to species. Thus, it is also a reliable basis to infer phylogenetic relationships.
Therefore, the right answer is option B, i.e., Morphology.

Note: The phylogenetic relationships tell about the time when two species shared a common ancestor. Thus, one can infer the evolutionary relations shared by two or more species. This information can be used to trace back to the time of the origin of a particular species. This knowledge helps one to understand the various developmental aspects of a species based on its evolution.