March 24, 2015 | David F. Coppedge

Animals Wonderful and Bizarre

The variety of living organisms on our planet is astonishing and often surprising. Here are a few examples that have come to light in news reports.

Whale size colony: Imagine colonies of individual organisms that grow into hollow tubes as long as whales and also glow in the dark. That’s what New Scientist reveals about pyrosomes. They’re rarely seen, but a video clip in the article shows one in action.

Pyrosomes are made up of hundreds or thousands of clones called zooids. The entire brightly lit colony sprouts from a single individual, and the zooids mesh themselves together as the colony grows outwards in concentric circles from a closed tip to an ever-widening mouth. When the colony is small it looks rather like a butterfly net. As it lengthens, it becomes more like a giant worm that can reach the length of a sperm whale.

The zooids can reproduce by cloning, so the colony can regenerate injured parts and theoretically live forever, shrinking and growing based on available food and physical disturbance.

Hearing without ears: Speaking of whales, they have no external ears. Instead, National Geographic says, they receive underwater sounds through their jaws and the fats adjacent to them. The jawbones act as antennae to funnel the sounds into the fats, which reach the bones of the middle ears that are disconnected from the skull. The isolation of the middle and inner ear gives the whale the ability to hear in 3-D without the external ears that land mammals use—that’s why we humans can’t understand things underwater as well as in the air. (Whale hearing and echolocation will be featured in Illustra Media’s new documentary Living Waters, due out this summer.)

Fast decision makers: As we reported on 3/18/15, pigeons are capable of making split-second decisions in flight. Bats, too, are capable of making hunting decisions in “an extremely short time,” Science Daily reports. Researchers at the University of Southern Denmark tested this by yanking prey right at the last moment before the catch. The bats were able to adjust in just 20-100 milliseconds. This is not just reflex or autopilot, the researchers concluded; it’s actual reaction time based on visual input. We are sad to have to award Stupid Evolution Quote of the Week to one of the researchers:

Signe Brinkløv thinks that bats’ ability to make quick decisions is a result of evolution.

“They rely on being able to react extremely quickly when they hunt, so I would think that they’ve been under strong evolutionary pressure to develop such expedited reactions in order to survive as a species,” she says.

Squid editors:  When molecular machines transcribe DNA, it sets in motion a team of editors who craft the messenger RNAs before they reach the ribosome, where the mRNA is translated to protein. PhysOrg says that squid, equipped with a rather slim set of genes, perform “prolific RNA editing” to enrich their genetic toolkit. Some 60% of its transcripts had been edited, geneticists at the University of Puerto Rico found. This overthrows the “Central Dogma” of genetics, the article says (i.e., DNA makes RNA makes protein). The extensive alternative splicing in squid helps explain how very different organisms can grow from the set of genes common to them all.  One species, the common squid, Doryteuthis pealeii, is “a behaviorally sophisticated marine organism that has long been prized for studies of the nervous system.”

Fish out of water: Mudskippers are amazing little fish that can hunt for food on land. PhysOrg tells how they form a sort of “tongue” of water to ingest their prey. Videos in the article filmed in super slow-mo show how they do it. Unfortunately, most reporters consider this an evolutionary stepping stone: “Consequently, although alternative scenarios cannot be excluded, hydrodynamic tongue usage may be a transitional step onto which the evolution of adhesive mucosa and intrinsic lingual muscles can be added to gain further independence from water for terrestrial foraging.”

Wolf in fish clothes: Mimicry and camouflage are big topics in ecology. A reef fish named the dusky dottyback has the ability to change colors to match the parents of its prey. Normally gray, it can turn yellow to fit in with the “safe” fish. In a video clip in an article on The Conversation, biologist Fabio Cortesi of the University of Basel describes how they conducted experiments to see if this form of mimicry made the dottyback more successful at hunting. He calls it the “wolf in sheep’s clothing” strategy. The video begins with dramatic music like an epic movie as the predator sneaks up and grabs its prey. The findings are only a small part of a bigger question about reef communities; “What we’re interested in is to know why there are so many different colored fish, why there are so many species, and how they interact with one another,” Cortesi says.

Aerial gyroscopes: Flying insects can use their wings as gyroscopes, Science Daily reports.  Biologists have surmised that the stubby “halteres” on dipteran flies can be used this way, but now, it appears that many other kinds of flyers have sensors in the joints of the wing muscles that provide stability. “I was surprised at the results,” said Brad Dickerson, a graduate student in biology and co-author of the study. “This idea of wings being gyroscopes has existed for a long time, but this paper is the first to really address how that would be possible.”

Spiderman worm: The velvet worm can quickly shoot out a sticky web that hardens in seconds. New Scientist shows a video of how it generates its high-pressure jet of fluid.  Sounds gruesome, but engineers look at this and get ideas for ink-jet printing, soft sutures, or a new kind of taser that could stop criminals in their tracks.

Did you notice how evolutionary theory provided no useful information in these stories? Entertainment, maybe, but not understanding.

 

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