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. 

All complex life, including plants, animals and fungi, consists if of eukaryotic cells, cells with a nucleus, transport mechanisms and often organelles like mitochondria that perform the functions an organism needs to stay alive and healthy. Humans have 220 different kinds of eukaryotic cells which control everything from thinking and locomotion to reproduction and immune defense.

Because of that commonality, the evolution of the eukaryotic cell is considered one of the most critical events in the history of life on Earth. Without it, earth populated entirely by prokaryotes, single-celled organisms such as bacteria and archaea, with no chance at all of filming "Guardians of the Galaxy" or celebrating Christmas.

Skin color varies according to latitude and therefore by the intensity of incident ultraviolet light; according to biologists, that is why individuals living at low latitudes developed darker skin, whereas those living at high latitudes ended up with paler pigmentation. 

Yet the mutations that lightened the skin, probably owing to the need to synthesize vitamin D at latitudes with less solar irradiation, also increase the probability of developing melanoma or skin cancer, which is a negative in natural selection. 

In the last 20,000 years, Europeans and Asians became numerous and their descendants now comprise the bulk of our 7 billion population. Prior to that, for 130,000 years, the Khoisan (they call themselves Bushmen), of Namibia reigned supreme.

Their lifestyles remain relatively primitive. And genetically, they have not changed all that much either. They number only about 100,000 and a study in Nature Communications compared nearly all the genes of these individuals -- their genomes -- with the genomes of people from around the world, and discovered that the inflow of new genes into the Bushmen has been quite restricted the past 150,000 years.

Usually blind sages revealing the secrets of the universe are Asian. Scotland doesn't get enough respect that way but a centipede is defying the stereotype.

Arthropods are one of Earth's real success stories, with more species than any other animal phylum. Genome sequencing has been skewed towards the more popular insects, and even an arachnid and a crustacean, and now finally the myriapods (centipedes and millipedes) are emerging from the dark.

Insects are the most diverse group of animals on earth. They inhabit nearly all terrestrial habitats. One of the factors underlying this success is the ability of insect eggs to survive in adverse conditions.

For a long time the ability to survive these adverse conditions has been attributed to maternal investment in the form of a protective eggshell. However, my research in the red flour beetle (Tribolium castaneum) shows that contrary to common belief, insect eggs are far from helpless.