ALL CREATURES BIG AND SMALL – PART 1: UNDERWATER SURVIVAL

Recently an Instagram follower posted this comment:  “U post interesting pics! :-).”  That day I had posted , among others, the following ( @cgurmann, if you want to follow my other photographic exploits):

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As you can see my obsessions are very eclectic; in fact, there are times when the plethora of interests almost overwhelms me! This proved true during my recent visit to a preview showing of a new exhibit at the American Museum of Natural History.  Therefore my musings will take form in a series of posts so as not to overwhelm you.  I have also attached a number of videos that I hope you will watch.

The exhibit, which opens on April 4,  is called “Life At the Limits,” is an exploration of the distinctive and sometimes shocking efforts by animals and plants to survive, reproduce and prosper. A brilliantly innovative winding pathway was chock-full of models, video, “smellovision” (will explain that in a later post) text and even live animals to help illustrate the ways these living creatures wend their way through sometimes hostile, and even lethal environments. Today’s post will concentrate on my favorite underwater beasties.

AXOLOTL – The Axolotl is a bit like a science experiment gone a bit haywire. Although technically a salamander, unlike amphibians that metamorph from egg to larva to adult, the axolotl never leaves its larval form, keeping its feathery gills and fins.  It also has the ability to regenerate limbs so it easily relinquishes a leg to a predator during its escape, knowing it can grow another.  It’s name comes from the Aztec word “Nahuatl,” which means “water-dog,” but while kinda cute, I don’t see the resemblance:

Live, not Memorex (I know this dates me)

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NORTHERN ATLANTIC SEA SCALLOPS – Two rows of bright blue eyes with acute vision, sensing light and movement – perfect receptors to notice predators such as starfish, lobsters, urchins or sea snails (or perhaps the pugilistic peacock mantis shrimp below) sneaking up for a snack.  When danger is sensed. the scallop employs a quick getaway by using its large muscle to snap their shell open and closed, forcing water out and jet propelling them to safety:

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NAUTILUS – My first reaction to seeing the tank full of Nautilii (sp?) below was one of shock – I thought these shelled creatures were long extinct.  Turns out I was partially correct as the species does date back 500 million years, although the first of its kind were called Lituites which were straight shelled. The present day Nautilus are multi-chambered (the chambers are added as the animal grows, but it only lives in the latest layer)and they live about 20 years but don’t sexually mature until 15 years of age. Like the scallop, the prime mode of escaping danger is jet propulsion with an extra twist. Not only does the Nautilus draw water into its chambers, it also can adjust its buoyancy through osmosis (passing water in and out of its blood cells).  The Nautilus is not as smart as its cousins, the octopus and squid nor is its eyesight as acute, but it does have pretty good short-term memory:

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PEACOCK MANTIS SHRIMP – While the first two animals are rather passive, choosing to swim away from danger, this next fellow is downright feisty.  The Peacock Mantis Shrimp,  which can grow up to 7 inches in length and is vivdly-colored  – packs a wallop with its club-like appendages that at rest are held bent below its body  (thus the nickname “praying mantis”). Its punch is so powerful that it is equal in speed to a .22 caliber bullet (50 times faster than the blink of an eye).  It also has exceptional eyesight with the most complex eyes in the animal kingdom. This shrimp has 16 color-receptive cones compared to humans, who have just three so it can detect ten times more color than a human, including ultraviolet light. It can also move each eye independently increasing its ability to see predator and prey:

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HYDROTHERMAL TUBEWORMS – They may look like plants, but these are enormous invertebrate worms that can grow up to 8 feet long.  These are peaceful creatures that have an extraordinary ability to live and thrive in a most hostile environment of hydrothermal vents created by underwater volcanoes.  Super-heated, almost boiling water from the volcano seeps through faults in rock, bringing with it a poisonous soup of chemicals and minerals. With no sunlight for energy, or even mouths or digestive tracts, these worms find sustenance from tiny bacteria that extract energy from the chemicals by way of chemosynthesis (synthesis of organic compounds by energy from inorganic chemical reactions). As they “eat, they exude a dark inky substance, thereby securing the moniker “black smokers:”

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TARDIGRADE – These are by far my most favorite creatures of this exhibit, even though they are microscopic – only 0.059 of an inch big. Tiny they are but oh so tenacious, so much so that they have actually been sent into outer space!

These segmented, 8 legged micro-animals were originally called named “Kleiner Wassrbar”meaning “little water-bear” due to its lumbering bear-like gait in 1773 and finally Tardigrada” meaning “slow stepper in 1776. They are asexual, meaning they reproduce via parthenogenesis (development of an unfertilized “gamete” – cells that can join to gether to make a living creature).

What makes the Tardigrade so freaking awesome is its perseverance in the face of seemingly deadly surroundings such as:

Temperatures  below -330 F. or as high as 300 F.

Freezing and Thawing – boiling water or freezing ice

Lack of water or oxygen

Low pressure of a vacuum or the high pressure 6 times that exerted by the deepest ocean water

Radiation that is 1000 times greater than a dose lethal to humans

Tardigrades are so amazing!  If conditions become perilous, the Tardigrade dries itself out completely by replacing almost all the water in their bodies with a sugar called trehalose and subsequently reversing the process once the danger has passed.  To test this hardiness, Tardigrades were sent into outer space in 2007, exposing them to cosmic and UV radiation and vacuum conditions, and most of them survived.  I am sure the government is feverishly trying to figure out how to harness this.

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Next up we emerge from the water to explore some land marvels!  Stay tuned!

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