one direction through the body of the bird. In humans, the air we breath in and out travels back and forth along the same tubes. In birds, as well as some of their close dinosaurian cousins, these air sacs would have have allowed the air to flow more efficiently through their bodies. While this is simply one of many adaptations that can help birds fly at incredibly high altitudes, other animals have evolved other adaptations to assist in high altitude living. Scientists have determined that changes in the genes EGLN1 and EPAS1 are linked with animals living in oxygen impoverished environments, such as the snow leopard, humans native to Tibet, and naked mole rats. Naked mole rats live in underground colonies of 20-300 individuals, and are one of two species of mammal that can be classified as "eusocial," meaning that their colonies display a caste system (similar to the social structure seen in ant and termite colonies). These underground colonies are poorly ventilated, which means that as the mole rats inhale oxygen and exhale carbon dioxide, CO2 concentrations can increase to levels that would be unsafe for humans. Fortunately, naked mole rats are well adapted to breathing very little oxygen, and their brains seem incapable of registering pain upon contact with acids, which is thought to help them in these CO2 rich confines. They also demonstrate similar changes in the aforementioned genes as snow leopards and the Tibetan people, indicating another adaptation to these low oxygen (or hypoxic) conditions.
|A group of naked mole rats all huddled together at the Cheyenne Mountain Zoo in Colorado Springs, Colorado. Look at all of that eusociality!|
|A drawing of Opabinia, one of the many creatures that inhabited the Cambrian aged Burgess Shale in British Columbia, Canada. Photo Credit: Sam Lippincott|
plants have got our back, by undergoing a process called photosynthesis. Photosynthesis is almost the exact opposite of respiration: carbon dioxide and water are the inputs, and glucose and oxygen are the outputs. However, unlike respiration, light is one of the inputs of photosynthesis. In the 1700s, a man named Joseph Priestly did experiments in which he sealed a mouse in a jar, and waited to see what happened. The mouse, as you could probably predict, suffocated and died. It used up its oxygen to create energy (as well as carbon dioxide), and eventually ran out of oxygen. (This is why it's important not to put animals into completely sealed jars with no airflow, as they will suffocate.) However, if he put a plant into the same jar as the mouse, the mouse didn't suffocate. We now know that is because, as the mouse used up the oxygen, creating carbon dioxide, the plant would use the carbon dioxide, ultimately creating more oxygen.
Sun for its energy. That is, until 1977, when scientists discovered entire communities of biological organisms living thousands of meters beneath the surface of the ocean, too far from any sunlight to undergo photosynthesis. So what was going on? How were these communities able to survive without access to the sunlight?
|A picture of one of the hydrothermal vent communities. Photo Credit: NOAA|
Jupiter's moons, Europa. Icier than the planet Hoth, Europa is now thought to have an ocean of liquid water up to 160 km (100 miles) deep surrounding the solid, rocky mantle, following the discovery of a magnetic field surrounding the moon, similar to the magnetic field that surrounds the Earth.
|A picture of Jupiter's moon Europa, taken by NASA. Photo Credit:|
|Jupiter and its four Galilean Moons (from top to bottom: Io, Europa, Ganymede, and Callisto). Photo Credit: NASA|