Dinosaur Fish Doomed To Extinction

The Pallid Sturgeon is a fish that lives in the Missouri River, which flows from Montana to where the river empties in Mississippi River. These fish are considered "dinosaur fish" and have survived for millions of years. They have no teeth, no rib cage, and are covered in bony scales, yet have managed to survive longer than dinosaurs have.

However, due to the recent installation of dams along the river, their population has dwindled down to about 125 fish. The fish deposit eggs into the water, that must move along with the current. The dams, however, do not allow the eggs to continue on their travels and they get caught in reservoirs, that are filled with bacteria and don't allow the eggs to get oxygen. In turn, the eggs suffocate and eventually die. This has had a serious effect on the population of pallid sturgeons, which has been been very concerning. The only way to save these creatures is to change the dams into an pump irrigation system. This switch is anywhere from $80 to $138 million. With that cost the fate of these dinosaur fish is left up to the court. 

A Swordfish's Best Kept Secret

Reaching unofficial speeds around 60mph, a swordfish can impress almost anyone with its great speed.  Scientists recently have identified one aspect of the fish that may contribute to this ability.  A specific type of oil is secreted and covers the head of the fish allowing it to be even more hydrodynamic than originally designed.

Dutch researchers examining two frozen swordfish discovered that there is an oil-producing gland at the base of the sword, connected by capillaries to pores in the skin of the head.

Scientists believe that this advantage assists the speed of the swordfish by 20%.  The oil is secreted from the glands as the water goes past the skin of the fish giving it the advantage it needs to escape a predator and catch its prey!

Some Fish can handle the heat

I found this article and it discusses how tropical fish have a better tolerance for the high and rising temperatures in the sea. They were said to evolve over several generations and appear to have a better capacity to deal with the heat than other fish. This is crucial for the survival of these fish due to the rising temperatures from global warming and can inevitably prevent them from becoming extinct and dying off. They tested this theory by exposing damsel fish to temperatures that were 1.5 to 3.0 degrees higher than normal there was a decline in their aerobic capacity. When compared to the fish that were bred for several generations there was almost a complete environmental adjustment with the offspring in the higher temperatured water . This happens because when the one generation goes through their life cycle in warm temperatured water the next generation that comes up is better able to cope with the temperature. So its pretty amazing to see the adaptations these fish can make from generation to generation. My guess is that if the water temperature got colder these fish could make these same adaptations as they did with the warmer water as well.

New Found Squid: Any Sex Will Do

New York Times - Sept. 20, 2011
 
   In this extremely interesting article, scientists have found a new creature in the dark waters of the Pacific Ocean. Octopoteuthis deletron, the newly discovered squid, carries similar characteristics to mammals such as bottlenose dolphins and bonobos. They all have no particular preference when it comes to mating.
     The mating process for this particular squid is interesting to say the least. Not much is known in great detail, but it is described as a male squid ejaculating a packet of sperm at the partner, male or female. The sperm is contained in a membrane that shoots into the flesh of the receiver. If the male happens to mate with a female, the sperm remains inside of the female until the female is fertile and able to produce eggs. The male however remains stuck with the sperm.
     This, by far, was the most intriguing article I found. I understand that there are millions of creatures that we have yet to discover, but yet I am still amazed when reading about each new finding.

Dolphins Quick Healing

From Science Daily, an article from Georgetown University Medical Center explains the research referring to dolphins and their ability to heal quickly. The article proposed different reasons for such an ability and how they are able to keep their shape after healing from a large gash, such as a shark bite.

They release a compound that helps fight infections. When cut, their blood is not near the surface therefore, they do not loose as much blood and are able to survive and heal quickly. The healing ability is "less like human healing and more like regeneration." Scientists are interested in finding out if the unique dolphin abilities can assist human injuries.

Jawless Fish Demise Still A Mystery

According to the New York Times, jawless fish may have died off for reasons other than not being efficient predators. Jaws first appeared on fish around 420 million years ago. Prior to this, fish sucked their prey through their mouths. Today, however, only two types of jawless fish remain, lampreys and hagfish. A study that was performed shows that jawless fish coexisted with jawed fish for 10 to 20 million years. This lead them to question whether competition was the downfall of jawless fish. Dr. Philip Anderson, an evolutionary paleobiologist at the University of Bristol in England, studies fossils to research jaws. He found that 10 million years after the first jawed fish appeared, there were a variety of distinct jaws. Slender jaws for capturing, and thick and robust jaws for power appeared amongst others. A study suggests that perhaps jawless fish utilized different resources to survive longer. Although, no definitive answer is known right now, the scientists firmly believe that competition with jawed fish is not the key reason for their demise.

Chewing Evolution

An article in Science Daily described the research ongoing at Brown University concerning the evolution of the tongue in different organisms. Every organism has their own way of getting the nutrition they need in order to survive. Specifically, fish, mammals, and amphibians were used in their research. They all used their tongue for the process of digestion, but in different ways.

Research at Brown University found that fish use their tongue in order to thrust food backwards further into their system. On the other hand, mammals use their tongue for better placement of food in the mouth to chew.

The researchers were curious as to where the split in evolution took place between the two types of tongue movements. Amphibians seemed to be the answer because of their tongue characteristics which Brown University plans to further research.

Rotting fish

Could scientists be wrong about where some animals fall into the tree of life?  Some researchers in England think it is possible. They theorize that some primitive animals have been miss classified because of the way their fossils have been found. They believe that important information in missing because these animals are believed to only have soft tissue. They argue that that tissue could have decomposed long before a fossil could preserve the information.   To prove their theory they decided to study the decomposition on some fish with similar characteristics. 

No one was there 500 million years ago to say this is what happened, and without actual fossil records it will be difficult to prove. I think this is an interesting way of gathering information that might help to decode the fossils that did survive. 

http://www.scientificamerican.com/article.cfm?id=early-vertebrate-evolution