Lizards, frogs, lampreys, and some fish species possess a unique organ known as a third, or parietal, eye. Though referred to as an “eye,” this photoreceptive organ does not “see” in the same way that a standard eye does. Instead, it uses a different biochemical method of detecting light than normal eyes and helps regulate circadian rhythms and hormone production for thermoregulation. The parietal eye is associated with what gland that humans, too, possess? Discuss
Biologically speaking, senescence is the process of deterioration that follows the development of an organism. In 1965, Leonard Hayflick discovered that normal diploid cells divide in cell culture about 50 times before entering a senescence phase during which they can replicate no more. Each cell division shortens the telomere of the cell’s DNA, thus ticking back an “inner clock” for each subsequent copy of the cell. How does this mechanism protect the body from disease?
Definition: (adjective) Tending towards an earlier worse condition; declining or deteriorating.
Synonyms: deteriorating, backward, regressive, retrogressive.
Usage: It would be a retrograde step to revert to the old system.
Commonly called fireflies or lightning bugs, the carnivorous beetles of the family Lampyridae are named for their use of bioluminescence when attracting mates or prey. Fireflies are capable of producing red, yellow, or green “cold light” containing no ultraviolet or infrared rays. Approximately 90% of the energy used in the process is converted to visible light—compared to 10% for incandescent electric bulbs, which emit the remainder of their energy as heat. How do fireflies produce their light? Discuss
Definition: (noun) A toxic alkaloid found in certain tropical South American trees that is a powerful relaxant for striated muscles.
Usage: The arrow was usually tipped with a poison, such as curare, which would stun or kill the struck prey.