Sexual reproduction would have been more challenging for some species of dinosaurs than others. If you’ve never given the matter much thought, think for a minute about how the Stegosaurus – together with their sharp back plates and tail spikes – might have gone about continuing their lineage:

Heinrich Mallison, a scientist at the Museum of Natural History in Berlin, has developed computerized models showing the numerous positions available to lusty dinosaurs. His software models proved that the male Kentrosaurus (a relative of Stegosaurus) had a major obstacle to overcome; namely, castration by the female’s sharp-spined back. “These prickly dinosaurs must have had sex another way,” Mallison told the Times. “Perhaps the female lay down on her side and the male reared up to rest his torso over her. Other species would have used different positions, like backing up to each other.”

A bottle garden, or terrarium, has been thriving inside a ten gallon glass container that has been sealed since 1972, and has not needed watering, pruning, or any other sort of maintenance, aside from a little exposure to sunlight, the whole time. Now that’s my idea of the perfect garden.

Photosynthesis creates oxygen and also puts more moisture in the air. The moisture builds up inside the bottle and “rains” back down on the plant. The leaves it drops rot at the bottom of the bottle, creating the carbon dioxide also needed for photosynthesis and nutrients which it absorbs through its roots.

Great care is taken by scientists at NASA’s Office of Planetary Protection to ensure that space probes sent to other planets and moons in the solar system are not carrying any traces of bacteria or microbes from Earth… seeding another planetary body with some sort of life-form from here would, after all, be the last thing anyone wanted.

A space vehicle we’ve sent to a distant planet to search for life touches down in an icy area. The heat from the spacecraft’s internal power system warms the ice, and water forms below the landing gear of the craft. And on the landing gear is something found on every surface on planet Earth… bacteria. Lots of them. Specifically spore-forming bacteria which can survive extremely harsh conditions, for years. If those spore-forming bacteria found themselves in a moist environment with a temperature range they could tolerate, they might just make themselves at home and thrive and then, well… the extraterrestrial life that we’d been searching for might just turn out to be Earth life we introduced.

A virus with its own immune system sounds like a medical nightmare – surely it could fend off the medicines sent to treat it – but such organisms, and there’s a few about it seems, could however be used to attack bacteria:

The scientists, led by Andrew Camilli, stumbled across the virus while studying the bacteria that causes cholera, known as Vibrio cholerae. Scientists have long known that V. cholerae gets infected by viruses. In fact, there’s some evidence suggesting that these viruses can bring cholera outbreaks to a halt. As the V. cholerae hosts multiply, their viruses multiply even faster, until they send the bacteria’s population crashing down. Camilli and his colleagues set out to survey these viruses, to see how many species were making life hard for the bacteria.

The tensile strength of human skin has recently been gauged, thanks to tests on cadavers:

The first detailed study of skin strength was carried out in the 1860s by Karl Langer, an Austrian anatomist working in Vienna. He mapped the natural lines of tension within skin by puncturing the skin on a cadaver with a circular tool and then measuring the shape of the resulting hole. The tension within the skin makes these holes elliptical in a direction parallel to the tension. Consequently, a simple measurement of the orientation of these ellipses allowed Langer to map out lines of force in the skin over the entire body. Today, these lines are known as Langer lines.

I would like to think that our skin is strong enough and serves its purpose… without subjecting it to extremes of force or treatment.

The mass extinction that killed off some 90 percent of animal, plant, and insect species on Earth around 251 million years ago, could be attributable to an ocean residing microbe called methanosarcina, thinks Massachusetts Institute of Technology researcher Daniel Rothman:

Called methanosarcina, this sea-dwelling microbe is responsible for most of the methane produced biologically even today. Rothman and his team discovered that methanosarcina developed the ability to produce methane 231 million years ago. While that ability came around too late to be single-handedly responsible for the link. However, mathanosarcina requires nickel in order to produce methane quickly. Nickel levels spiked almost 251 million years ago, likely because of a spike in Siberian lava from the volcanoes themselves. This indicates that methanosarcina was directly responsible for producing the methane that killed off an overwhelming majority of the Earth’s species.

Bound to hotly disputed but will surely make for a talking point or two over the year-end break.

Scientists are already aware that animals and plants living in urban centres, such as New York City, are evolving to adapt to the conditions around them, and even differ genetically from others of their species elsewhere, and now it looks like the same can be said of river crabs living in the very centre of Rome:

On its own, the story of the crabs in Rome is an interesting tale of the persistence of nature despite us. These crabs certainly make one wonder what else can be found up Rome’s cloaca. But there is more to the story. When Scalici and colleagues described the biology of the Roman crabs – having studied more than four hundred of them and compared them to populations from across Italy, they found that they were, well, “different.” They were slower growing but lived longer, and so ended up being roughly one and half times as big as other crabs of the same species. They were urban, modern, and fat. They also appeared to mate at a different time of year than do the other river crabs.

The genetic make-up of insects, animals, and other organisms living in urban centres has been found to differ from those of the same species living in other locations, as city dwelling creatures adapt to their environments.

White-footed mice, stranded on isolated urban islands, are evolving to adapt to urban stress. Fish in the Hudson have evolved to cope with poisons in the water. Native ants find refuge in the median strips on Broadway. And more familiar urban organisms, like bedbugs, rats and bacteria, also mutate and change in response to the pressures of the metropolis. In short, the process of evolution is responding to New York and other cities the way it has responded to countless environmental changes over the past few billion years. Life adapts.

Good question, if there are different species of fish for instance, why is there only the one human species? Well, until relatively recently, at least on universal time scales, Homo sapiens shared the planet with other humans, including Homo erectus, Neanderthals, and Homo floresiensis, who died out about 12,000 years ago.

Planning, communication and even trade led, among other things, to the development of better tools and weapons which spread rapidly across the population. The fossil records suggest that H. erectus went on making the same basic hand axe for more than a million years. Our ancestors, by contrast, created smaller, more sophisticated weapons, like a spear, which can be thrown, with obvious advantages when it comes to hunting and to fighting. The same advantages helped Homo sapiens outcompete another rival human, the Neanderthals, who died out about 30,000 years ago as the Ice Age limited available food supplies.

Mathematical concepts are increasingly being applied in the field of biology, not only bringing about a new branch of science called biomathematics, but also creating an opportunity for scientists to make sense of long standing biological puzzles.

I would be surprised if mathematics ever came to dominate biological thinking in the way it does physics, but it is rapidly becoming an essential part of the discipline: 21st-century biology makes use of mathematics in ways that no one would have dreamed of at the start of the 20th. By the time we get to the 22nd, mathematics and biology will have changed each other beyond all recognition, just as mathematics and physics did in the 19th and 20th centuries