Evolution

We like to think of evolution as a fine-tuning process, one that whittles away genetic imperfections and redundancies and converges on a more efficient system because of 'survival of the fittest'.

But natural selection is just one mechanism of evolution and what is fittest at one point may not have been fittest at another, yet could still be inherited. Our bodies are full of parts that we inherited and either don't work anymore or are rather buggy and other parts have simply found a way to make work.


Most people think that biting is the way that aquatic creatures capture prey. Not so, instead suction is far more common.

That is why the diversity of skull shapes in biters is so much greater, according to a new study. Suction feeding limits skulls shapes because of the structural requirements for suction feeding. 

"When you look at the skulls of biters, the diversity is astounding compared to suction feeders," said Rita Mehta, assistant professor of ecology and evolutionary biology at U.C. Santa Cruz. 



The human Y chromosome has retained only 3% of its ancestral genes. So why is it a shadow of its former self? Rafael Anderson Gonzales Mendoza/Flickr, CC BY-NC-SA

By Jenny Graves, La Trobe University

The Y chromosome, that little chain of genes that determines the sex of humans, is not as tough as you might think. In fact, if we look at the Y chromosome over the course of our evolution we’ve seen it shrink at an alarming rate.


The bobtail squid and bioluminscent bacteria are just one of hundreds of examples of mutualism. Klaus Stiefel/Flickr, CC BY-NC

By Alex Jordan, University of Texas at Austin

The 1KITE project (1,000 Insect Transcriptome Evolution) seeks to understand the millions of living insect species that shape our terrestrial living space and both support and threaten our natural resources by analyzing more than 1,000 insect transcriptomes, a set of all RNA molecules.

Using a dataset consisting of 144 carefully chosen species, 1KITE scientists have just presented reliable estimates on the dates of origin and relationships of all major insect groups based on the enormous molecular dataset they collected. They show that insects originated at the same time as the earliest terrestrial plants about 480 million years ago.
8 percent of our genome derives from retroviruses that inserted themselves into human sex cells millions of years ago and right now the koala retrovirus (KoRV) is invading koala genomes.

Koalas are the only known organism where a retrovirus is transitioning from exogenous to endogenous. An exogenous retrovirus infects a host, inserts its genetic information into the cell’s DNA, and uses the host cell’s machinery to manufacture more viruses. When an exogenous retrovirus infects an egg or sperm cell and the viral genetic information is then passed down to the host’s offspring, the virus becomes an endogenous retrovirus (ERV). 

Scientists believe that Eurasians separated into at least three populations around 36,000 years ago: Europeans,Asians and a mystery third lineage, all whose descendants would develop the unique features of most non-African peoples after interbreeding with Neanderthals. 

A new study on DNA recovered from a fossil of one of the earliest known Europeans, who lived 36,000 years ago in Kostenki, western Russia, has shown that the earliest European humans' genetic ancestry survived the Last Glacial Maximum - the peak point of the last ice age. 


Nature enjoys variety, that is why it seems like evolution must have been drinking during the creation of some of the crazier things in biology. 

There is no intelligent reason why snakes and lizards have two genitalia while birds and people have one - or why the former group's paired structures are located somewhat at the level of the limbs while with humans and birds it appears a bit further down. In fact, snake and lizard genitalia are derived from tissue that gives rise to hind legs, while mammalian genitalia are derived from the tail bud. But despite such noteworthy contrasts, these structures are functionally analogous and express similar genes. 

How do these equivalent structures arise from different starting tissues? 


Biology can be inspirational.  The spiral ramps in multistory parking garages, the way they are stacked and connecting parallel levels, are replications of helical structures found in a ubiquitous membrane structure in the cells of the body - Terasaki ramps in an organelle called the endoplasmic reticulum (ER), a network of membranes found throughout the cell and connected to and surrounding the cell nucleus.

A team of researchers have described endoplasmic reticulum geometry using the language of theoretical physics in Physical Review Letters.



By Sarah King, Genetic Literacy Project

Since the discovery in 2004 of Homo floresiensis, an ancient hominid nicknamed “Flo” and also “hobbit”, after the diminutive villagers from J.R.R. Tolkien’s Lord of the Rings trilogy, due to her small size relative to modern humans, much debate has been raised over the origins of the species.