Evolution on Polypompholyx

Stems all the way down

Fri, 07 Jul 2017 15:14:03 +0000

In the days when potted plants were more than just disposable land-filler, my Nan would try to force her wizened poinsettia to flower by sticking it into a bin-liner with some apples every night from October until December. Sum total of flowers she ever saw: zero. Ho hum. But how many poinsettia flowers can you see in the picture below?

Poinsettia (Euphorbia pulcherrima)

If you’re wondering whether you can include the ones that are partly off-screen, you are asking the wrong question. There are many hundreds of flowers here, not six or ten. The red leafy-looking things you might have been cruelly mislead into thinking were petals are actually brightly coloured leaves. The flowers themselves are found in the tiny yellow-green blobs in the middle…

Adaptations evolve in populations

Thu, 05 May 2016 18:35:46 +0000

Organisms evolve adaptations to increase their fitness

There are few ideas in science that explain as much of the natural world as does natural selection, but there are few ideas in science that are more frequently misunderstood.

Often the misunderstandings are deliberate or disingenuous, but I’ve seen quotes like the one above even in undergraduate essays and popular science books.

Phage vs. host

Fri, 10 Jul 2015 10:21:09 +0000

For a recent schools’ outreach day, I put together a card-game based around the arms-races that develop between bacterial hosts and their viruses (bacteriophages). It’s mostly just a bit of fun, but if anyone finds it useful or can suggest improvements (or just make them! I release this under a CC-BY-SA-4.0 license) I’d be happy to hear them.

Organism of the week #20 - Don't point that thing at me

Thu, 06 Mar 2014 08:56:50 +0000

It’s amazing how informative an anus can be.

Take this sea urchin. The orange pucker in the middle of the spines is its “around-the-bum”, although zoologists would insist on writing that in Greek as “periproct”. The bright orange ring-piece is characteristic of this species, and marks it out as Diadema setosum, rather than any of the less rectally blessed species of Diadema.

Organism of the week #14 - Turtles all the way down

Sun, 26 May 2013 16:00:02 +0000

Cassiopea, which looks rather like a spelling mistake (but isn’t), also looks a bit like an anemone (but isn’t):

Cassiopea 'upside-down jellyfish' in the aquarium beneath the Palm House at Kew Gardens

It’s actually a jellyfish, but one that spends most of its time living upside-down (relative to its relatives). Unlike its close relatives, it gets much of its energy from sunbathing rather than from fishing.

Organism of the week #11 - Not even primitive

Mon, 08 Apr 2013 15:53:49 +0000

It’s not much to look at, but Psilotum nudum‘s naked fronds* *hold a cautionary tale for biologists:

Psilotum nudum, finally bagged at the Oxford Botanic Gardens

Psilotum looks a great deal like some of the earliest fossils of land plants. One of the earliest such fossils is Rhynia, the first specimens of which which were unearthed in Aberdeenshire around 1910, a mere 410 million years after they were originally buried.

Vegetable empire 2013

Fri, 29 Mar 2013 23:07:26 +0000

By popular demand, I have resurrected this phylogeny from my old website for Easter 2013. I have added a number of extra groups, updated the angiosperms according to APG-III, and repositioned the Gnetales according the apparently ascendent gnetifer hypothesis. The rotated titles in the table appear to work in IE9, Chrome and Safari, but YMMV.

Far from the light of day, and somewhere near Hampstead

Tue, 25 Sep 2012 19:33:09 +0000

Paddock is the codename of a bunker that was built in the late 1930s as a back-up for the better known Cabinet War Rooms located in Whitehall.

Junction box in the upper basement floor of the Paddock bunker; CWR-AWR almost certainly stands for 'Cabinet War Room - Air Raid Warning'

The bunker was abandoned at the end of the war, and was only used intermittently after that by the Post Office, whose Research Station sat atop it. In 1998, the surface site and the bunker were sold off, and a housing development was built on top. Unfortunately, during the development, the concrete slab that kept the bunker watertight was damaged, and since then, Paddock has been slowly decaying.

A brief history of rubbish

Mon, 10 Sep 2012 15:10:42 +0000

In 1972, the geneticist Susumu Ohno coined the term “junk DNA” to explain why the genomes of closely related organisms vary so much in size:

The mammalian genome […] contains roughly […] 3.0 × 10⁹ base pairs. This is at least 750 times the genome size of E. coli. If we take the simplistic assumption that the number of genes contained is proportional to to the genome size, we would have to conclude that 3 million genes or so are contained in our genome. The falseness of such an assumption becomes clear when we realize that the genome of the lowly lungfish and salamanders can be 36 times greater than our own.

Ohno, S. (1972) So much ‘junk’ DNA in our genome, In: Smith, H. H. (ed) Evolution of genetic systems, 23, 366-370.

The magnolia misunderstanding

Thu, 26 Jul 2012 12:30:50 +0000

T. Ryan Gregory has a great post at Genomicron on the ‘Platypus Fallacy’. He imagines a platypus professor explaining the wonders of the Human Genome Project to a group of student platypodes:

“The lineage of which humans are a part is a very ancient offshoot of our mammalian family tree, so it was 166 million years ago that we last shared a common ancestor with humans, and that puts them somewhere between mammals and reptiles, because they lack a lot of specialized characters that we have gained but the ancestral amniote also lacked; for instance, they have no electroreception, no bills, no webbed feet, and no venom. So we can use them to trace the changes that have occurred as we went from being a reptile, to having fur to making milk to having our specialized features.”

Why living fossils need to die

Fri, 27 Apr 2012 16:02:52 +0000

I’m the proud owner of a Madagascan cycad. He or she (I won’t know until s/he gets older) gets an annual decking with baubles at Christmas, but spends most of the rest of the year getting in the way of the television.

Deck the cycad with Pantone baubles, fa-la-la-la-lah la-la-la-lah

Cycads look a lot like palms, but rather than producing flowers and fruits, they make cones and bear fruitless naked seeds. This hints at their origins. They are much more closely related to pine trees and other gymnosperms, than to flowering plants like palms.