Category — Biology

Computational biologists and ecologists at various leading US Universities have discovered an interesting use for Google’sPageRank, the algorithm that determines which pages are considered most important for displaying search results.  They’ve modified PageRank for modelling fragile ecosystems – in particular, they’re using it to determine which species are most critical, the ones whose extinction will most likely lead to total ecosystem collapse.  From the Wired article:

“While several previous studies have looked at the robustness of food webs to a variety of sequences of species loss, none of them have come up with a way to identify the most devastating sequence of extinctions,” said food web biologist Jennifer Dunne of the Santa Fe Institute, who was not involved in the research. Using a modified version of PageRank, Dunne said, the researchers were able to identify which species extinctions within a food web would lead to biggest chain-reaction of species death.

“If we can find the way of removing species so that the destruction of the ecosystem is the fastest, it means we’re ranking species by their importance,” said ecologist Stefano Allesina of the University of California, Santa Barbara, who co-authored the paper published Friday in PLoS Computational Biology.”

This kind of research can help determine which species need the most protection.  Not only that, but PageRank is attracting interest from other biologists who see it as a promising approach to intricate problems like gene regulation and protein interaction.  [Check out this post's mirror on w0rd.ca!]

I saw this story the other day, about a chimp at a zoo in Sweden with a penchant for throwing rocks at zoo visitors.  The stone throwing itself isn’t noteworthy; chimps throw all kinds of things at people (and each other) all the time.  What makes this story unique is that the chimp has also been observed collecting rocks from around his pen area, which he was only later using as projectiles.  Biologists are in a tizzy over this, claiming that it’s the first unambiguous example of a non-human animal peforming a pre-meditated action.  While chimps have been observed performing any number of complex behaviours (including tool use), the behavioural biologists studying this chimp say that it’s the first example of a non-human animal acting in the present (rock collecting) to fulfill a future need (the desire to throw the rocks), rather than a present need.

This has led to speculation over what kind of inner mental life other animals experience, with the biolgists having this to say about chimps:

“It implies that they have a highly developed consciousness, including life-like mental simulations of potential events. They most probably have an ‘inner world’ like we have when reviewing past episodes of our lives or thinking of days to come. When wild chimps collect stones or go out to war, they probably plan this in advance. I would guess that they plan much of their everyday behavior.”

Interesting stuff, and I don’t think many people would be surprised at the idea that other animals (especially primates) experience rich inner mental states the way humans do and have fairly complex notions of past, present and future.  

What bothers me about this story is that I have a hard time believing this is the very first example of this kind of behaviour.  People have been studying primate behaviour for decades, there must be some previous example in the literature of an animal unambiguously planning ahead.  Even people who aren’t professional behavioural biologists have seen this kind of thing: anyone who grew up with a dog has probably seen them bury a bone or toy, and then come back for it later.  Isn’t that a fairly unambiguous example?  I don’t want to eat this now, so I’m going to bury it where no one will find it, because I know I’ll want to eat it later.  Perhaps I’m confusing that with a more primitive form of behaviour.  Any behavioural biologists out there who’d like to clear this up for me?

A new study out of the University of Exeter once again shows that Dolphins are more advanced than we might have thought.  In this study, they were observed partaking in sophisticated food preparation:

“The research team, writing in the science journal PLoS One, said they repeatedly observed a female dolphin herding cuttlefish out of algal weed and onto a clear, sandy patch of seafloor.  The dolphin, identified using circular body scars, then pinned the cuttlefish with its snout while standing on its head, before killing it instantly with a rapid downward thrust and “loud click” audible to divers as the hard cuttlebone broke.  The dolphin then lifted the body up and beat it with her nose to drain the toxic black ink that cuttlefish squirt into the water to defend themselves when attacked.  Next the prey was taken back to the seafloor, where the dolphin scraped it along the sand to strip out the cuttlebone, making the cuttlefish soft for eating.”

It’s not exactly haute cuisine, but this type of behaviour has never been observed outside of the higher primates.  Pretty amazing for a species that doesn’t even have hands!

It’s not quite Jurassic Park, but for the first time scientists have brought a species back from extinction by cloning:

“The Pyrenean ibex, a form of wild mountain goat, was officially declared extinct in 2000 when the last-known animal of its kind was found dead in northern Spain.  Shortly before its death, scientists preserved skin samples of the goat, a subspecies of the Spanish ibex that live in mountain ranges across the country, in liquid nitrogen.  Using DNA taken from these skin samples, the scientists were able to replace the genetic material in eggs from domestic goats, to clone a female Pyrenean ibex, or bucardo as they are known. It is the first time an extinct animal has been cloned.”

Unfortunately, the animal died shortly after birth due to a lung defect, a common problem among cloned animals of similar type.  While we’re still a long way from bringing back more long-dead species (hello, T-Rex!), this is an intriguing step in the evolution of cloning technology.

Sex in space has always been a bit of a taboo subject, at least as far as the public face of agencies like NASA and the RFSA are concerned.  I’ve always been baffled and disappointed by their singular tactic of deny, deny, deny every time someone brings up the possibility that two Astro/Cosmonauts might have been getting it on.  It’s as if they’re worried that admitting to/allowing sex on missions will somehow  make it seem that they aren’t really in the business of conducting serious science.  I mean, really; putting people in space and conducting experiments on everything from physics to botany to animal physiology isn’t enough?  In-orbit sexual encounters between two consenting adults are somehow going to tear down their image as credible scientific and technological institutions? [Read more →]