If you think it is impressive that primates have managed to survive on Earth for 50 million years, then you will find it phenomenal that trilobites managed to survive for a staggering period of 270 million years. First appearing on Earth about 521 million years ago during the early Cambrian period (when life on Earth began to complexify in incredible ways), they finally became fully extinct around 252 million years ago, during the late Permian period, and were probably the most abundant animal on Earth at that time. This is one testament to their immense success as an organism; another being the fact that their fossils are found widely dispersed on Earth – on every continent in fact – and palaeobiologists have named over 15,000 species of trilobites. So what made them so successful as an organism?
We’ve heard of many animals gone extinct – the dodo, the Tasmanian tiger; and we’ve heard of many being rediscovered by scientists after decades of ‘extinction’. This miraculous feat has once again been achieved in 2016, confirming the existence of another species previously thought to be extinct.
For over 40 years, the New Guinea Highland Wild Dog has been thought to be extinct in the wild. They are believed to be one of the rarest and most primitive species of canines, and a variant of the New Guinea Singing Dog (Canis dingo hallstromi) – the two are thought to once be the same species, before humans took wild dogs from the highlands and bred them into the Singing Dogs we know now. Although the Singing Dog are still bred in zoos, little has been heard of the Highland Wild Dog. However, in 2016, this all changed.
Organoids, it’s in the name. They are 3D, miniature and basic versions of organs that help scientists further understand the anatomy and function of various organs. Recently, researchers of Columbia University Medical Centre have created miniature lung organoids (as seen in the image bellow) to aid their knowledge on treating various diseases.
So how are they made? Technology has rapidly improved in the past 7 years and has been used for research in order to help scientists improve their understanding on biological functions. This technology began with attempts to create organs on a dish, which started as a dissociation – reaggregation experiment lead by Henry Van Peters Wilson. The results of this experiment showed that sponge cells could re-organise themselves after being separated, back into one whole organism. After this experiment, there were many similar experiments that were able to generate different types of organs artificially through the dissociation and reaggregation of organ tissues. These experiments often used amphibians as their subjects.
Imagine a world where, just like in food, human genes can be edited, giving people the power and ability to eradicate genetic disorders, but also unjustly provide a portion of people in the future with advantages over others. For better or for worse, this is likely to soon become a reality, with the recent invention and refinement of the genome editing tool ‘CRISPR-Cas9’.
Every aspect of who we are is determined by our genes, which are tiny units of heredity made up of DNA, which act as instructions for the production of proteins. It is estimated that humans have approximately 20,000 to 25,000 genes in total and although most of our genes are the same between all humans, the 1% or so that aren’t, are what gives each of us our individual traits. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats and was originally discovered in certain species of archaea in 1993 by Francisco Mojica. Between then and 2013, scientists across the globe worked on developing a way to use this discovery to their advantage, ending up with CRISPR-Cas9. It differs from all previously developed gene editing tools and techniques because it requires considerably less time and effort to execute, and is substantially cheaper. The actual process does not require a lot of human involvement, because Cas9 (the enzyme that alters the gene) is “led” by guide RNA to the correct location, making CRISPR-Cas9 the most accurate gene editing tool yet.
Tardigrades (Phylum: Tardigrada), also known as water bears, were first discovered by the German zoologist, Johann August Ephraim in 1773. They are water-dwelling micro-animals with eight legs and can reach a maximum size of 1.5mm. Now over 1000 individual species of tardigrades have been discovered to this day.
Tardigrades are some of the most resilient animals known and can be found in almost every environment, ranging from tropical rainforests to Antarctica, and even your own backyard! It is said that these tardigrades get to all these different places by being carried by wind and water currents and then deposited somewhere far away. If you have a microscope, it is actually possible to find your own wild tardigrades!
These water bears are renowned for their ability to survive extreme environmental stresses that would kill almost any other animal, such as being dehydrated, exposed to excessive amounts of gamma radiation and coping with pressures as high as 600 mega-pascals (MPa) – pressures that are beyond anything they might encounter in nature. They can also tolerate being frozen to -272.8 °C (which is just above absolute zero), as well as being heated to 151°C for 15 minutes and still bounce back to life. Not to mention, they can healthily reproduce in outer space! If you were to go into outer space without protection, you will die in only a matter of 15 seconds. The low pressure would force the air out of your lungs and the fluids in your body will expand, causing you inflate. Your capillaries would rupture and the ionising radiation would destroy the DNA in your cells.
So, the question is, how are tardigrades able to survive in these extreme conditions?