Vasotocin is present in nonmammalian vertebrates and shares structural and functional properties with mammalian antidiuretic hormone and oxytocin. Through these similarities it has been suggested that vasotocin could be the ancestral precursor to the posterior pituitary hormone in vertebrates.

Question

Answer the following statement true (T) or false (F)

Answer 1

True

Clarify Question


What is the key concept addressed by the question?
     • This question is asking you to determine if the data provided support the idea that vasotocin could be an ancestral hormone from which other hormones of the posterior pituitary have evolved.
What type of thinking is required?
     • Apply level:
       o You are being asked to take what you already know and use, or apply, it to a situation where you have been provided evidence about the possible ancestral nature of a hormone.


Gather Content


What do you already know about the evolution of hormones? What other information is related to the question?
     • To answer this question you need to recall that the hormones of the posterior pituitary, oxytocin and ADH, are structurally similar.
     • Additionally, to answer this question you should recall that even though mammals are the only animals to have oxytocin and ADH, other nonmammalian vertebrates produce a hormone that has chemical similarities to each of those hormones.
     • Finally, to answer this question you should recall that it is believed that the vasotocin gene is thought to have undergone gene duplication in the mammalian lineage and that the evolution of oxytocin and ADH was possible due to the presence of two genes.


Choose Answer


Given what you now know, what information is most likely to produce the correct answer?
     • At this point you should have everything you need to answer the question. The process of maintaining salt and water balance is broadly found among the animals whereas the process of lactation is unique to mammals. These processes are regulated by hormones from the endocrine system that have a great deal of structural similarity and are thought to have evolved from a common gene.


Reflect on Process


Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
     • Apply level:
     o Answering this question correctly depended on your ability to use your understanding of hormone evolution in a new situation. If you got an incorrect answer, did you remember that hormone evolution likely required gene duplication events in the past, or that both oxytocin and ADH are only found in mammals? Did you have trouble extending your understanding of hormone evolution to determine the correct answer?