Evolution


Fish vision just got more complex. Janderk, CC BY-SA

By William Feeney, University of Cambridge

A recently published study offers new clues about the evolution of the immune system in European populations of the plant Arabidopsis thaliana and the underlying genetic mechanisms associated with immunity. 
The species Arabidopsis thaliana, which is naturally distributed across the northern hemisphere, belongs to the same family than mustard. The species is used as model in plant biology studies because its genome is relatively small and appropriate for genetic studies.

A study using geckos has found that evolution can downgrade or entirely remove adaptations that have been previously acquired, giving the species new survival advantages. 


In many species of plants and animals, individuals from the same population often come in different color variants. It's always been that way but why one color doesn't eventually replace the others through natural selection is something of an evolutionary biology mystery.

Namely, how and why do variants of the same animal exist in nature? In theory, different color morphs (variants) should be equally subjected to natural selection. 
Northern Europeans pride themselves on being tougher than the rest of Europe when it comes to enduring weather. While most people are more likely to die in bad weather, a new paper finds that Norwegian kids were more likely to die when the weather was good.

By studying church records from 1750 to 1900 and looking at life history variables, such as how old women were when they had their first child and their last and how many years passed between the birth of each child and how many of these children survived, Gine Roll Skjaervoe at the Norwegian University of Science and Technology's (NTNU) Department of Biology made a strange finding - kids born in years with a lot of sunshine died more, and that meant fewer grandchildren. 
Ribosomes: squiggly and yummy. crobin, CC BY

By Robert Root-Bernstein, Michigan State University and Meredith Root-Bernstein, Aarhus University

Since the discovery of how DNA encodes genetic information, evolutionary biology has focused on genes. One popular hypothesis - the "selfish gene" theory - states that cells and organisms exist simply as packages to protect and transmit genes.

The selfish gene is by no means accepted and a new paper gives biological 'selfishness' itself a twist, and proposes that if anything is "selfish" it must be the ribosome. That might change everything the public thinks they know about the evolution of life and, in fact, the function of ribosomes themselves.

Modern human skeletons, with our lightly-built form, evolved only relatively recently, after the start of the Holocene about 12,000 years ago and even more recently in some human populations, according to a study that used high-resolution imaging of bone joints from modern humans and chimpanzees as well as from fossils of extinct human species.

For millions of years, extinct human predecessors had high bone density. A higher decrease in the density of lower limbs than in that of the upper limbs suggests that the transformation may be linked to humans' shift from a foraging lifestyle to a sedentary agricultural one.


 Edentulism, the absence of teeth, has evolved on multiple occasions within vertebrates including birds, turtles, and a few groups of mammals such as anteaters, baleen whales and pangolins, but where early birds are concerned, the fossil record is fragmentary.

A question that has intrigued biologists is whether teeth were lost in the common ancestor of all living birds or convergently in two or more independent lineages of birds.

A research team using the degraded remnants of tooth genes in birds to determine when birds lost their teeth believes that teeth were lost in the common ancestor of all living birds more than 100 million years ago.

The evolutionary adaptations of ancient lobe-finned fish transformed pectoral fins used underwater into strong, bony structures that enabled emerging tetrapods, animals with limbs, to allow them crawl in shallow water or on land. 

The disconnect between paleontology and evolutionary biology has been why the modern structure called the autopod, comprising wrists and fingers or ankles and toes, has no obvious morphological counterpart in the fins of living fishes.