Magoosh Toefl Reading Practice -

However, this form of communication carries risks. Predators may eavesdrop on these light signals, detecting prey that flash too frequently or brightly. In response, some species have evolved “private channels” by producing light outside the visual range of common predators or by using extremely brief flashes that are difficult to locate. As one marine biologist noted, “In the deep sea, every light signal is a gamble between being understood by a friend and being eaten by an enemy.” 1. According to paragraph 2, how does counter-illumination camouflage benefit hatchetfish?

The deep ocean, defined as depths below 200 meters, exists in perpetual darkness. Sunlight cannot penetrate this far, yet the region teems with life. To navigate, hunt, and mate in this lightless environment, many species have evolved bioluminescence—the production and emission of light by a living organism. Unlike the bioluminescence seen in fireflies, which occurs on land, deep-sea bioluminescence is almost exclusively blue-green in color, because these wavelengths travel farthest in seawater. magoosh toefl reading practice

Perhaps the most intriguing use of bioluminescence is in communication. Research conducted in the 1990s aboard submersible vehicles revealed that many deep-sea organisms produce species-specific flash patterns. These patterns help individuals recognize members of their own species for mating, avoid hybridization, and even coordinate group movements. Squid, shrimp, and certain jellyfish have all demonstrated the ability to alter the duration, frequency, and intensity of their light pulses. However, this form of communication carries risks