The Beautiful Life of the Leopard Slug

The Leopard slug has migrated to North America from Europe and much to the dismay of gardeners and squeamish 5 year olds they can be found anywhere from underneath boards and rocks to inside flower pots. The Leopard slug is unusually slimy with an overall tawny brown, a light "sole" and attractively spotted and streaked with dark brown. It is as beautiful as a common garden pest could possibly be.

The Leopard slug is claimed to have an unusually wild sex life. The slugs do not have distinct genders and are hermaphrodites, meaning, more likely than not both will leave the sex encounter pregnant. They will then find a dark, damp spot and deposit about 200 large. clear eggs.

What is interesting about Leopard slug mating is one member of the pair will overhang on a ledge or branch on a long bungee made of their own slime. The pair will intertwine hanging on the mucus and exchange their spermatophores. Fortunately, this ritual is performed exclusively after dark.

Slugs are gastropods and are distantly related to squids, oysters and snails. Did you know Leopard slugs do have a shell? It is hidden each one's mantle and looks like a small fold of skin or a fingernail, but is in fact a vestigial shell. If you stumble upon a Leopard slug on the streets of New York City are brave enough to squeeze it gently, you can feel the evolutionary evidence for yourself.

http://www.nytimes.com/2016/07/24/nyregion/the-double-life-of-the-slimy-acrobatic-leopard-slug.html?_r=0

http://www.molluscs.at/gastropoda/terrestrial.html?/gastropoda/terrestrial/limax.html

"Junk DNA" Responsible for Backbone Formation

Since the 1960s, scientists have researched non-coding portions of DNA within human and animal genomes. These portions, commonly called "junk DNA," are sections of the DNA sequence that are not responsible for the construction of the proteins that compose a living animal. As a result, many researchers believed the non-coding segments were left-over genetic debris from millions of years of evolution. In the last decade, the "junk" has been found to be anything but, as scientists think it could play an important role in evolution, such as body shape.

Recently, researchers led by developmental biologist Moises Mallo of the Gulbenkian Institute of Science in Oeiras, Portugal have examined mutant mice bred by the institute that contain 24 pairs of ribs, compared to the 13 pairs in normal mice. This mutation was traced back to the deactivation of the GDF11 junk gene, which controls another gene - OCT4 - that regulates stem cell development into many different cell types.

An x-ray of Moises Mallo's mice containing extra ribs.

Snakes, which also have both genes, naturally have dozens of ribs along the length of their spine. Mallo and his team spliced non-coding sections of snake DNA into normal mouse embryos near the OCT4 gene to see if the snake GDF11 would cause a prolonged growth spurt in the embryo. The team found that the embryos grew large amounts of additional spinal cord, implying that the junk DNA does indeed play a role in body shape regulation of animals.

Developmental biologist Valerie Wilson of the University of Edinburgh commented on the junk DNA:

“There’s an immense amount of variation in body length across vertebrates, but within species the number of ribs and so forth stays almost exactly the same. There must be some ways to alter the expression of those [genes] regulating evolution to generate this massive amount of variation that we see across the vertebrates.”

Read more: http://www.sciencemag.org/news/2016/08/junk-dna-tells-mice-and-snakes-how-grow-backbone

 

Endangered Caspian Seals

Recently, scientists have been doing research on Caspian seals, one of the world's endangered seal species. They discovered where, when, and how far they travel when they migrate and how they find food to eat. These seals like to separate into three groups when traveling: one in the shallow waters of the Caspian sea, another in the deep water off of Iran, and the final group on the edge of water areas in the north. The scientists on this project are still trying to figure out why some prefer longer distances over others. This information provides a lot of help for conservation efforts. The data can help identify the key areas that seals like to reside in which will provide useful when the humans are planning their activities such as building oil and gas developments. The scientists are currently using this information to get these species off of the endangered list. 

https://www.sciencedaily.com/releases/2016/08/160803111806.htm

Can a species that outlived dinosaurs, outlast a dam?

A fish species have outlasted dinosaurs are now being threatened to extinction by a dam in Montana. This "dinosaur fish" is called the pallid sturgeon. After millions of years of survival, there are now only 125 of this endangered species. These fish were once abundant along the Missouri river. This flowed east from Montana and south until it empties into the Mississippi river in Missouri. Pallid Sturgeons would swim up to spawn and their fertilized eggs developed as they drifted down the river. The Intake Diversion Dam in Montana provides water up to 55,000 acres of farmland. However, because of this dam, the sturgeons can't travel far enough up the fragmented rivers to ensure their eggs will make it to a healthy place to develop. They eggs get trapped in reservoirs that include a lot of sediment, bacteria, and very little oxygen. They suffocate and die there. One proposal that was brought up was to replace the Intake Diversion Dam with a new one and create a bypass channel to let the dinosaur fish get passed the dam. However, it was risky to rely on the sturgeons to navigate on their own. A better proposal was to get rid of the damn and replace it with irrigation pumps. It will cost more money but it has a higher rate of success.    




http://www.nytimes.com/2016/07/25/science/pallid-sturgeon-montana-yellowstone-river.html?rref=collection%2Fcolumn%2Ftrilobites&action=click&contentCollection=science&region=stream&module=stream_unit&version=latest&contentPlacement=10&pgtype=collection


https://www.fws.gov/Midwest/endangered/fishes/PallidSturgeon/index.html

Dolly the Sheep’s Fellow Clones, Enjoying Their Golden Years

Dolly the sheep was used for the study of cloning animals and whether if cloned animal would age prematurely. Scientists took a single adult cell, implanted into an egg cell where its own DNA was removed, and created an exact replica of its donor. Researchers explained that there were no abnormal deficiencies with the sheeps that were cloned but some appeared to show signs of osteoarthritis which Dolly was diagnosed with. Scientist declared that based on the new research cloning animals does not lead to the idea of premature aging.  

http://www.nytimes.com/2016/07/27/science/dolly-the-sheep-clones.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=stream&module=stream_unit&version=latest&contentPlacement=19&pgtype=sectionfront

https://sites.psu.edu/maddieleap16/2016/07/27/dollys-fellow-clones-enjoying-the-golden-years/

Not Just a Weed: Tires Made from Dandelions

Using thorough genome analysis and precision breeding, a pair of German scientists have doubled the amount of natural rubber produced by a specific strain of dandelion, a common and abundant weed. Researchers from the Fraunhofer Institute for Molecular Biology and Applied Ecology IME have successfully identified a cost-effective and eco-friendly alternative to the natural rubber tree, which has no synthetic replacement.

The rubber tree, or Hevea brasiliensis, is almost exclusively grown in the sub-tropical regions of Southeast Asia, and takes between 5-7 years to deliver its' first harvest. As global demand for rubber has grown, acres of precious rainforest have been converted into agricultural land.

Dandelions, on the other hand, are incredibly resilient, can grow in moderate climates, and can survive in soil unfit for the cultivation of food and feed crops. Additionally, they grow annually, so their rubber can be harvested on a more regular basis, consistent with the fluctuations of the rubber market.

The strain of dandelion, called the Russian dandelion, is cheaper and more sustainable than the natural rubber tree, however, it will not completely replace the traditional method of making rubber. To do so would require a plot of land the size of Austria completely dedicated to the cultivation of dandelions.

Tire company Continental has already created a prototype using the rubber, and their researcher, Dr. Carla Recker states, "the dandelion natural rubber has ideal material properties," and that "the tires are equivalent to those made from Hevea natural rubber."

Read more at: http://phys.org/news/2015-06-natural-rubber-dandelions.html#jCp

A Catalyst that Aided in the Extinction of the Mammoths

About 6,000 years ago there was a tiny island, called St. Paul Island, in the middle of the Bering Sea. It was a hundred miles away from the mainland. It only harbored a few species, including arctic foxes and woolly mammoths. One of the world's last populations of woolly mammoths have comfortably living in that are for for a few thousand years. They had a surplus of food, water, and lack of predators since humans got there at the 18th century. At this time there were drastic climate change that caused the sea levels to rise. This shrunk the land and herd size. Another negative effect was that because the climate was dry, there was less rainfall. This decreased lake levels. It ultimately decreased freshwater for the mammoths. Thus making drinking water more scarce. The rise of the sea also brought in more saltwater. This displaced the freshwater as well. Lack of freshwater was not the main cause of their extinction; however, it did play an indirect role in pushing the mammoths towards extinction.



http://www.nytimes.com/2016/08/02/science/mammoths-extinction-saint-paul-island-alaska.html?rref=collection%2Fcolumn%2Ftrilobites

http://www.nationalgeographic.com.au/history/why-did-the-woolly-mammoth-die-out.aspx