"Scandals" - Animals Evolved from Cancer Cells

Panchin knows the idea of cancer-derived animals sounds far-fetched — so much so that, in the paper, he and his co-authors refer to them as Scandals (an acronym for “speciated by cancer development animals”). [...] According to Panchin’s three-step scenario, a Scandal would start off as a cancer, but not just any cancer. It would have to be transmissible, so that it wouldn’t die when its host did. Then the cancer would have to spread to other species, and then independently evolve...

 Natural Selection Resembles Bayesian Inference

The analogy is mathematically precise, and fascinating. In rough terms, it says that the process of natural selection resembles the process of Bayesian inference. A population of organisms can be thought of as having various 'hypotheses' about how to survive—each hypothesis corresponding to a different allele. (Roughly, an allele is one of several alternative versions of a gene.) In each successive generation, the process of natural selection modifies the proportion of organisms having each...

 Unlike Physics, Biology Can't Ignore Information

Physicists love to think about systems that take only a little information to describe. So when they get a system that takes a lot of information to describe, they use a trick called 'statistical mechanics', where you try to ignore most of this information and focus on a few especially important variables. For example, if you hand a physicist a box of gas, they'll try to avoid thinking about the state of each atom, and instead focus on a few macroscopic quantities like the volume and total en...

 The Trick of Magnifying Normal Creatures

The trick of magnifying a normal creature to menacing size is all too common. The giant amoeba is a familar example; monster insects (or whole populations of them) even more so. It might pay an author with this particular urge to ask himself why we don't actually have such creatures around. There is likely to be a good reason, and if he doesn't know it perhaps he should do some research. In the case of both amoeba and insect, the so-called "square-cube" law is the trouble. Things like streng...

 The Need for an Internal Skeleton

The need for an internal skeleton stems largely from the nature of muscle tissue, which can exert force only by contracting and is therefore much more effective with a good lever system to work with. I belittle neither the intelligence nor the strength of the octopus; but in spite of Victor Hugo and most other writers of undersea adventure, the creature's boneless tentacles are not all that effective as handling organs. I don't mean that the octopus and his kin are helpless hunks of meat; but...

 Protocells

In 2007 two researchers, chemist Martin Hanczyc and artificial life scientist Takashi Ikegami, who were collaborating across disciplines agreed to test a hypothesis about the earliest forms of life (Hanczyc et al. 2007). They hypothesized that life’s precursors would need to move around their environment to take advantage of a resource-rich situation on early Earth. Hanczyc made a model system to test this hypothesis using an oil droplet that he bestowed with an internal chemical reaction, ...

 Squid Skin is Like an LED Screen

Television images are sometimes displayed on giant LED (Light Emitting Diode) hoardings. Instead of a fluorescent screen with an electron beam scanning side to side over it, the LED screen is a large array of tiny glowing lights, independently controllable. The lights are individually brightened or dimmed so that, from a distance, the whole matrix shimmers with moving pictures. The skin of a squid behaves like an LED screen. Instead of lights, squid skin is packed with thousands of tiny bags ...

 Error Catastrophe

The central problem for any theory of the origin of replication is the fact that a replicative apparatus has to function almost perfectly if it is to function at all. If it does not function perfectly, it will give rise to errors in replicating itself, and the errors will accumulate from generation to generation. The accumulation of errors will result in a progressive deterioration of the system until it is totally disorganized. This deterioration of the replicative apparatus is called the "e...

 The Mother's Womb Tests the Viability of the Fetus

Given the invasive nature of pregnancy, it’s perhaps not surprising that the primate womb has evolved to be wary of committing to it. Mammals whose placentae don’t breach the walls of the womb can simply abort or reabsorb unwanted foetuses at any stage of pregnancy. For primates, any such manoeuvre runs the risk of haemorrhage, as the placenta rips away from the mother’s enlarged and paralysed arterial system. And that, in a sentence, is why miscarriages are so dangerous. It’s also w...

 There is No Definition of "Species"

There is no authoritative definition of “species.” The most widely accepted definition describes a group of organisms that can procreate with one another and produce fertile offspring, but there are many exceptions. De-extinction operates under a different definition altogether. Revive & Restore hopes to create a bird that interacts with its ecosystem as the passenger pigeon did. If the new bird fills the same ecological niche, it will be successful; if not, back to the petri dish. �...