Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystemsof diverse fauna, i
Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystems
of diverse fauna, including several crustacean species, some of which undergo
development as larvae up to 1,000 meters above and 100 kilometers away from
Line the vents. For example, vent crab Bythograea thermydron (at stage of
(5) larvae) possess image-forming compound eyes with a visual pigment sensitive to
the blue light of upper oceanic waters. As these larvae metamorphose into
adulthood and begin to descend to and settle at the vents, they lose their image-
forming optics and develop high-sensitivity naked-retina eyes. With maturation,
the spectral absorbance of the visual pigment in these eyes also shifts towards
(10) longer wavelengths and this progressive visual metamorphosis trades imaging
for increased sensitivity, and changes spectral sensitivity to the dim, longer
wavelengths of light existing at the bottom of the ocean. As hydrothermal vents
produce light, vision may supplement thermal and chemical senses to orient
post-larval settlement at vent sites.
Which of the following is the most appropriate title for the passage?
A.Adaptive Visual Metamorphosis in Deep-Sea Vent Crabs
B.Aspects of the General Anatomical Development of Deep-Sea Vent Crabs
C.New Research Directions in the Study of Deep-Sea Vent Crabs
D.Common Features of Optics of Lower Depth Oceanic Animals
E.Patterns of Anatomical Transformation in Lower Oceanic Creatures