Take a Deep Breath!

Humans and marine mammals both belong to the class Mammalia, but how can marine mammals such as the seal, hold their breath under water for up to at least 30 minutes where Humans struggles even for 5 minutes.

Dr Michael Berenbrink and his team recently published an explanation on how marine mammals can store large amounts of oxygen.

The protein - myoglobin is used to store oxygen in mammals' muscle; this is what give muscles the red colour. In marine mammals, there are high concentrations of this protein in their muscles, causing them to appear black. In order for more oxygen to be stored in the muscles, much of myoglobin is needed. However, proteins tend to stick to each other at high concentrations - this causes clogging in the muscles and the loss of function of the proteins.

From tracing the changes of myoglobin through the evolutionary history of marine mammals, it was discovered that the protein evolved to have non-stick properties. Their myoglobin is positively charged and so will repel each other at high concentrations due to like charges. In this way, the animals can "pack" large amounts of oxygen in their muscles without clogging them up. 

This "physiological change" allows scientists to understand the transition of mammals from land to water and also estimate the dive time of e.g. whales from fossils. 

We are the Kings of Humanity!

Recently, an article has been published about a theory on the extinction of the Neanderthal. Neanderthals are an extincted species of the genus Homo (Homo neanderthals) which is very closely related to us; it is sometimes considered as a subspecies of Homo sapiens.

Neanderthals have a larger cranial capacity than modern humans indicating that their brains are larger as well. They are also stronger than humans, particularly their arms and hands. So, why did a species that is stronger and possibly be more intelligent than us become extinct when we are still in existence now?

Over the years, scientists have been suggesting hypotheses about the extinction of neanderthals. According to fossil records, neanderthals and modern humans coexisted several thousand years ago in Europe leading many scientist to believe that we were the reason why.

• Violence was one of the hypotheses - Jared Diamond suggested that the neanderthals suffered a series of conflict similar to the genocides. 

Genoides:- "the deliberate and systematic destruction in whole or part of an ethnic, racial, religious or national group."

• Parasites or pathogens - Due to the different lifestyles of modern human and neanderthals, the latter are more susceptible to pathogens.
• Competition - division of labour; both female and male neanderthals both took the occupation of hunting and did not have division of labour between the two sexes and so "resulted in the poor extraction of resources from the environment". Due to anatomical differences, the neanderthals require 30% more energy for running or walking than modern humans and so could not run as fast and so were not able to survive. The fact that humans have a relationship with dogs gave them an advantage in hunting whereas neanderthals did not have that relationship. 

• Interbreeding - As modern humans shares a lot of nuclear DNA with neanderthals, it is suggested that neanderthals interbred with the ancestors of modern humans and there was a variation in the genes leading to us today.
• Climate change

The recent theory that was published states that the neanderthals skull has larger eye sockets therefore they had bigger eyes and so their brain used more of its processing powers for visual images. Whilst humans used the processing power to to develop and work out the world we were living in, the neanderthals focused on processing image. This is believed to be because of the area in which they lived in - shorter days and longer nights resulting in lower light intensity. 

The reason that the neanderthals became extinct is still an unsolved puzzle and is still being investigated today.