In 1964, a graduate student named Donald Currey was studying the history of glaciers in Nevada, USA. He came across some bristlecone pine trees, which he suspected may give him some clues about the Ice Age. This is because previously, another scientist had discovered similar bristlecone pines nearby in California that dated between 3000-5000 years old.
So Currey decided to sample some of these trees to determine their ages. He thought that if he could show that the trees uphill were much younger than the trees at the base, it may prove that glaciers expanded down the mountain and pushed the trees back downhill.
Currey came across a particularly old-looking tree. He got permission from the Forest Service first, then cut the tree down to count its growth rings – the most accurate way to figure out how old a tree is. As the tree’s bark changes in a predictable fashion, a tree will gain one ring for every year of its life. An interesting point is that trees are often dated nowadays by taking a core sample instead of cutting it down (and thus killing it). It is uncertain why Currey and the Forest Service opted to cut the tree down instead.
After counting the rings of this tree, Currey realised that the tree (dubbed “Prometheus” by local naturalists) was 4844 years old – the oldest tree in existence in the world. Well, it was until it was cut down.
More modern analysis of Prometheus’ remains revealed that the tree was likely closer to just over 5000 years old at the time of its death, which makes Prometheus the oldest known tree and (non-clonal) organism in recorded history.
As expected, when Currey published his results, there was a massive outcry. In the name of understanding nature better, he inadvertently killed the world’s oldest tree.
Since the demise of Prometheus, another tree by the name of Methuselah has taken the crown of “oldest tree in the world”, at the age of 4852 as of 2020.
The lesson here is clear: before cutting a tree down, check that you are not accidentally killing the oldest tree in the world.
The liver is the second largest organ (next to the skin) in the human body, weighing about 1.4~1.6kg. It is found tucked under the right side of the ribcage, underneath the 5th to 10th rib in height and almost spanning the entire width of the trunk. When enlarged, the liver grows downward and can be felt in an abdominal exam (sometimes it is so large that it covers most of the abdomen).
It is a vital organ with many life-sustaining functions (hence “liver”) such as building various proteins, breaking down toxins, storing sugars in the form of glycogen, decomposing red blood cells and producing bile. The liver metabolises (breaks down) a large proportion of medications and drugs as it treats them as “toxins”. For example, the enzyme alcohol dehydrogenase breaks down alcohols into acetaldehyde, which causes hangovers and liver damage. Many Asians have a variant of this enzyme that is extremely efficient, causing a massive build-up of acetaldehyde when they drink alcohol. This is responsible for the so-called “Asian flush”.
Liver disease is associated a myriad of symptoms. The classic sign of jaundice(yellow skin and whites of eyes) is caused by obstruction of bile flow. Because of its location, pain in the right upper quadrant of the abdomen is commonly seen. As the liver is involved in synthesising various proteins, signs such as ascites (fluid in the abdomen) or bleeding may occur when the liver is damaged. A syndrome called portal hypertension is commonly seen in chronic liver disease such as cirrhosis as a major vein to the liver is blocked. This can cause an enlarged spleen, oesophageal varices that can bleed, ascites and prominent veins radiating from the belly button (caput medusae).
An interesting property of the liver is that it can regenerate at an amazing rate. A liver will regenerate to its original size even when a half of it is cut out (this is how live donor liver transplants work). What is more interesting is that the ancient Greeks probably knew of this fact as well. In Greek mythology, the gods punish Prometheus for bringing fire to humans by chaining him to a mountain and commanding an eagle to peck out his liver. The liver would then regenerate overnight and the eagle would return every morning to eviscerate him, causing him eternal anguish.