Evolution
As I was reading the comment section to “Our Anthropomorphic Bias” I was struck by the persistence shown by Sascha Vongehr in referring to humans as robots in 4 of the 5 comments he made in a discussion with Gerhard Adam. A couple of days later the puzzle was answered – Sascha submitted Robots Finally Awake in which he elaborated on the proposition that organisms are robots. (I did check the calendar to see if it was April Fools Day.) He had used Gerhard as a sounding board, and with no adverse reaction, felt secure enough to proceed with an article.
When I say that the idea was…
The Red Queen hypothesis, a popular idea in evolution named after Lewis Carroll's character who in "Through the Looking Glass" described her country as a place where "it takes all the running you can do, to keep in the same place", recently got studied by a group of researchers who were thinking beyond the death of individual species - they examined how the lack of new emerging species also contributes to extinction.
Environmental brochures highlight fears about groups of animals, such as frogs or the "big cats," going extinct. But in science that is only part of the story.
"…
In several posts the question of biological costs is invariably mentioned in discussing evolution. These costs are normally of the metabolic or fitness type. Metabolic costs are associated with the existence of a particular trait and the energy necessary for the trait's existence, while fitness costs are those that have an impact on the organism's ability to survive and reproduce (1).
In most instances, these concepts are taken from economic analogies, yet, like economics, the concept of cost is meaningless without a context. The two defining elements that must be considered…
Since 1996, farmers across the world have planted more than a billion acres of genetically modified corn and cotton that produce insecticidal proteins from the soil bacterium Bacillus thuringiensis, called Bt for short.
Bt proteins, used for decades in sprays by organic farmers, kill some devastating pests but are environmentally friendly and harmless to people. Some scientists have feared that widespread use of these proteins in genetically modified crops would spur rapid evolution of resistance in pests, while opponents predicted Armageddon due to such a biological arms race.
The…
In animals that reproduce by internal fertilization, as humans do, the penis is invaluable, from an evolutionary point of view.
Yet birds have evolved to not need them. Developmentally speaking, birds' penises have gone. Land fowl, which have only rudimentary penises as adults, have normally developing penises as early embryos. Later in development, however, the birds turn on a genetic program that leads their budding penises to stop growing and then wither away.
"Regulation of the balance between cell proliferation and cell death is essential for controlled growth and development…
In one sense, I am happy that there is enough interest in the concept of “junk DNA” (and by extension, my area of research in genome size evolution) that the subject gets regular media attention.
A few months ago, it was all about the ENCODE project and its “finding” of “function” for 80% of the human genome. This week, it’s a story that has the exact opposite message: that large amounts of so-called “junk DNA” can be deleted without apparent consequence. This most recent story was prompted by the publication of the genome sequence of the carnivorous plant known as the floating bladderwort.…
Stromatolites, "layered rocks", are structures made of calcium carbonate and shaped by the actions of photosynthetic cyanobacteria and other microbes that trapped and bound grains of coastal sediment into fine layers. They showed up in great abundance along shorelines all over the world about 3.5 billion years ago and remain the earliest visible manifestation of life on Earth.
The growing bacterial community secreted sticky compounds that bound the sediment grains around themselves, creating a mineral "microfabric" that accumulated to become massive formations. Stromatolites dominated…
As has been mentioned in other articles, evolution is one of the more misunderstood theories in biology. This isn't because it is complicated. Its beauty derives from its simplicity, but often the nuances that are overlooked.
We hear about "survival of the fittest" and many immediately think of strength. We hear about natural selection and many immediately focus on speciation. Yet, the first claim is simply wrong, while the second isn't the most important element of the theory.
So, if it's not about strength or how species originated, then what is important.…
Giant Leap Surplus To Requirements Say Evolution Scientists
I must confess that to the best of my knowledge, no scientist used those precise words. However, the research does indicate that what was previously thought to be a large change is the result of a few small steps.
It appears that, in evolution, small steps can lead to giant leaps.
In a newly published paper, scientists show that the human hip could have evolved from the equivalent bone structure of an ancestral fish in a few steps.
In a study published in the journal Evolution and Development,
Dr Catherine Boisvert of the…
The evolution of the complex, weight-bearing hips of walking animals from the basic hips of fish was a much simpler process than previously thought, according to a new paper.
Tetrapods, four-legged animals, first came to land about 395 million years ago - a significant step, literally and figuratively, and it was made possible by strong hipbones and a connection through the spine via an ilium, features that were not present in the fish ancestors of tetrapods.
The researchers compared the hip development, bones and musculature, of the Australian lung fish and the Axolotl, commonly known…