Question

1. a) A HOX gene called Pax6 is required for developing light sensing eyes (or eye-like structures) in a range of taxa including Cnidaria, Mollusca, Arthropoda, and Chordata. Humans (Chordata) and squid (Mollusca) have complex eyes with many shared features, like a lens, that are NOT found in other taxa that have eyes or eye-like structures. Which of the following statements is TRUE?

   		If human eyes and squid eyes are analogous, then the Pax6 gene in humans and squid will be nearly identical.
   		If human eyes and squid eyes are analogous, then their shared common ancestor would also have complex eyes.
   		If human eyes and squid eyes are homologous, then the Pax6 gene in humans and squid will be nearly identical.
   		If human eyes and squid eyes are homologous, then they have independent evolutionary origins.

b. Which of the following is NOT an evolutionary advantageous function performed by Seeds?

		The protective seed coat assists with water retention, allowing offspring to survive in drier environments.
		Seeds provide a structure that often facilitates dispersal of developing Sporophytes over much greater distances than in seedless plants.
		The enclosed nutrient supply allows the embryo to remain dormant for extended periods of time, until conditions are favorable for germination.
		Allows for transport of the male Gametophyte through wind-based or animal-based pollination, which eliminates the need for water to conduct fertilization.
		Trick question. All are functions that Seeds perform.

Answer 1

A. Pax6 is also known as master regulator gene for the development of eyes. It is highly conserved across species.

The evolution is convergent means different genes started functioning in the same so the eyes are not homologous but analogous. It has been studied that 69.3% of the genes examined are commonly expressed in the camera eyes of human and octopus. Means gene expression patterns in both the eyes of humans and octopuses are remarkably similar. So option B should be correct.

B. All the above statements about seed are correct with respect to evolutionary advantage. Because seeds carry nutrients, depend very less on water for germination because it can be dispersed by air or other insects as it is quite light in weight, provides more protection to physical stress, and can disperse in different ways when compared with spores for pollination. Seeds have endosperm which is used for providing nutrient to the developing embryo.