Multipore Sea Star – Linckia muitifora Interestingly the Multipore exhibits autotomy (self amputation) and often sheds one or more arms. In this process, the arms become detached at various positions and each can grow into a new individual. This happens with such frequency that it is considered to be a means of asexual reproduction. Few individuals are found that do not exhibit some evidence of prior autotomy. Individuals always lose their largest arm to autotomy. From the “tail” of the comet, the arm that was dropped off, 4 arms are slowly growing back to form a new complete sea star. As the process continues, the little arms grow bigger, and they will eventually end up looking like stars again. It appears that most of the populations can be made up of these comet individuals. The sexual (gonochoric) produced embryos hatch into planktonic larvae spending up to two years in this stage before settleing and metamorphose into pentamorous juveniles which develop into young sea stars with stubby arms.
In a study on Hawaii, it was found that the detachment of an arm is not caused by a sudden snap. Most fractures take place about 1 inch from the disk. A small crack appears on the lower surface which spreads to adjacent parts, then the tube feet on the arm and the body pull the two parts of the animal in opposite directions. The event may take about one hour to complete. The damaged tissues take about 10 days to heal and the animal grows a new arm over the course of several months. The detached arm is known as a “comet” and moves about independently. It takes about 10 months to regenerate a new disk with arms 0.5 inch in length.
Sea stars can probably undergo asexual reproduction more easily than other animals because they have most of their organs repeated in each of their arms. Also, they don’t have a centralized nervous system, it would probably be a trickier thing to do if they also had to regenerate a full brain. Because of the position of their mouth, it is also one of the first thing to be regrown, so they don’t have to starve for too long before they can feed again. If many species of sea stars can regrow a missing arm, only a few can, like Linckia multifora, regrow a full animal from just an arm.
Etymology Linclda – The genus is named after the German naturalist Johann Heinrich Linck muitifora – multi– ‘much or many’ and +fora = ‘forum’?
Halley’s Comet is arguably the most famous comet. It is a “periodic” comet
and returns to Earth’s vicinity about every 75 years, making it
possible for a human to see it twice in his or her lifetime. The last
time it was here was in 1986, and it is projected to return in 2061.
Humpback whale feeding on herring. It scientific name is Megaptera and literally means mega wings.
Etymology Humpback – is derived from the curving of their backs when diving. Megaptera – Greek mega– “giant” + ptera ‘wing’ refers to their large front flippers. novaeangliae – French = “New Englander” and was probably given by Brisson due to regular sightings of humpbacks off the coast of New England.
The distinctive ‘horns’ on either side of its broad head are actually derived from the pectoral fins. During embryonic development, part of the pectoral fin breaks away and moves forward, surround the mouth. The way the horns develop is surprisingly simple. All it takes is a tiny notch that deepens and widens as the manta grows, separating each fin into two distinct parts: one for feeding and the remainder for swimming. This give the manta ray the distinction of being the only jawed vertebrate to have novel limbs. These flexible horns are used to direct plankton into its mouth.
Oh, give me a horn on the sides of my head Where I keep them rolled up all tight; And where the food is just right I reach out to bite And the plankton is funneled precisely in. Chorus Horns Horns on my head…
After feeding, each limpet will return to the spot on the rocks from which it set out. A limpets can live for many years and it always returns to the same point. Over the years it wears an oval mark on the rock called a ‘Home Scar.’
A Nautical mile is based on the circumference of the earth, and is equal to one minute of latitude (1/60th of a degree). It is slightly more than a statute mile (1 nautical mile = 1.1508 statute miles.) Nautical miles are used for charting and navigating.
Side note: Degrees of latitude are parallel so the distance between each degree remains almost constant but since degrees of longitude are farthest apart at the equator and converge at the poles, their distance varies greatly.
Each degree of latitude is approximately 69 miles (111 kilometers) apart. The range varies (due to the earth’s slightly ellipsoid shape) from 68.703 miles (110.567 km) at the equator to 69.407 (111.699 km) at the poles. This is convenient because each minute (1/60th of a degree) is approximately one nautical mile.
A degree of longitude is widest at the equator at 69.172 miles (111.321) and gradually shrinks to zero at the poles.
Turtle Fact Adult female sea turtles are literally magnetically drawn to the comforting beaches here they were hatched. What’s more, scientists suspect that tiny magnetic particles in the sea turtles brain enable them to detect unique magnetic signatures given off by beaches, such that they can return to them after ultra-long journeys.
Creole wrasse – Clepticus parrae – are protogynous hermaphrodites; the largest fish in a group is a dominant breeding male, While smaller fish remain female. If the dominant male dies, the largest female changes sex.
Protogyny is the most common form of hermaphroditism in fish in nature. About 75% of the 500 known sequentially hermaphroditic fish species are protogynous.
Wrasses are always on the go during the day, but are the first to go to bed and the last to rise.
Etymology Clepticus: Greek, kleptikos = ‘related to thieves’