Yesterday we tried to place the Holocene-Anthropocene Mass Extinction in the context of Earth’s past mass extinctions. Listing the Holocene Extinction as the ‘Sixth Mass Extinction’ proves problematic for various reasons. Today we offer additional context: although a mass extinction … Continue reading →
All the leaves are brown and the sky is grey – which means it’s time for the Geological Society of America annual meeting. A couple of days packed with discussions and research presentations about stuff you did not know in … Continue reading →
Doesn’t the Tree of Life make for a beautiful infographic? Shown is bird evolution according to the Hackett backbone tree – one of two studied by the researchers. Using the world’s first family tree linking every known bird species, scientists … Continue reading →
Living systems owe their existence to a pair of information-carrying molecules: DNA and RNA. These fundamental chemical forms possess two features essential for life: they display heredity — meaning they can encode and pass on genetic information, and they can adapt over time, through processes of Darwinian evolution.
A long-debated question is whether heredity and evolution could be performed by molecules other than DNA and RNA.
In the last century something unexpected happened: humans became sedentary. We traded in our active lifestyles for a more immobile existence. But these were not the conditions under which we evolved. David Raichlen from the University of Arizona, USA, explains that our hunter-gatherer predecessors were long-distance endurance athletes. ‘Aerobic activity has played a role in the evolution of lots of different systems in the human body, which may explain why aerobic exercise seems to be so good for us’, says Raichlen. However, he points out that testing the hypothesis that we evolved for high-endurance performance is problematic, because most other mammalian endurance athletes are quadrupedal. ‘So we got interested in the brain as a way to look at whether evolution generated exercise behaviours in humans through motivation pathways’, says Raichlen.
Life on Earth consists of many millions of species, divided into ever smaller numbers when you zoom out to Genus, Family, Order, Class, Phylum and Kingdom – of which there are six. When you divide in Domains, there are just … Continue reading →