A falcon’s eye view of flight

September 27, 2010

This video has been doing the rounds, and its so cool I just have to post it here.  The video shows the amazing maneuverability and speed of birds of prey in flight, thanks to “on bird” cameras mounted on a peregrine falcon and a goshawk.

hat-tip: Ars technica


Update on 10,000 genomes and tasmanian devils

September 27, 2010

A while back I wrote about the Genome 10K project, an ambitious initiative from a consortium of mostly US-based researchers to sequence 10,000 vertebrate genomes.  Recently BGI (formerly known as the Beijing Genomics Institute)  embarked on a similar project, aiming to sequence 1000 plant and animal genomes to create a library of digital life, and in May they announced that they would sequence the first 100 vertebrate genomes for the Genome 10K project.   BGI have invested $100m into the digital library project, enabling them to fully fund some genome projects, and partially fund others.

The 100 species to be included in the Genome 10K project are being chosen on the basis of their biology, diversity, specimen availability, and the existence of a scientific community with expertise in the species.  And if your favourite genome is not on their current to-do list, don’t despair, as BGI are calling for proposals for other genomes to sequence.

Last week I went along to a seminar by representatives from BGI at Victoria University.  I was kind of blown away by their the sheer size and scale of their operation – they have a workforce of about 3000 people and billions of dollars in facilities all dedicated to pumping out and assembling DNA sequence, and really seem to be taking over the world when it comes to genomics.

But one genome that BGI hasn’t been sequencing is the tasmanian devil.  Its been a big month for tassie devil news:  first from the fight against devil facial tumour disease,  the news that Cedric, an animal with a putative “resistant” genotype, had died of the disease; and secondly the announcement that the tasmanian devil genome has been sequenced.  The genome was sequenced by the Wellcome Trust Sanger Institute in the UK.  They have  sequenced the genome of a healthy tasmanian devil plus two independent tumour samples, in the hope that they will be able to pinpoint mutations that will improve understanding of the disease and how it spreads.


Tuatara Tuesday – Stephens Island

September 21, 2010

This little guy lives on Stephens Island in the Marlborough Sounds, and is affectionately known as “tree tut” to the Victoria University researchers who frequent the island.  Because he lives in a tree, of course.  His tree is along the pathway between the house occupied by the DoC rangers and the house where the researchers stay, so he has plenty of passing foot traffic to keep an eye on.

Stephens Island is tuatara central, home to a staggering 30,000 – 50,000 individuals.  Given that the island is only about 150 ha in size, this means that tuatara are EVERYWHERE on the island and it is sometimes difficult to avoid treading on them.  Stephens Island has an interesting history, which may have partly contributed to the high densities of tuatara found there.  A lighthouse was constructed on the island in 1893, and three houses were also built to accommodate lighthouse keepers and their families.  During World War II a radar station was set up there, and an accommodation building known as the “Palace” was constructed.  The Palace is still there and these days serves as a lab and storage shed.

The clearing of land for the construction of the lighthouse and houses, and the introduction of cattle and sheep decimated the Stephens Island forest, and photos of the island from 50 years ago or so show barren hillsides with only a few remnant patches of bush.   However, for the last 20 years a revegetation program has been in full swing and the forest is returning.  The lighthouse was automated in 1988, and the last lighthouse keeper left the island in January 1989.  The last sheep left the island in 2005, and today the only permanent human presence on the island are the DOC rangers, who live in one of the old lighthouse keeper’s houses.

Despite the human settlement and rampant habitat destruction, the only introduced predators that made it to the island were the lighthouse keeper’s cats.  These cats decimated some of the local wildlife, including the Stephens Island wren, an unusual flightless passerine which famously went extinct virtually as soon as it was discovered.  However, the tuatara population escaped virtually unscathed and cats were eradicated in 1925 after only about 30 years on the island.  Ironically, the clearing of forest on the island may have actually increased tuatara numbers, by increasing the availability of suitable nesting sites in open areas.  The island currently appears to be above its carrying capacity, and once the forest regeneration is complete tuatara numbers may decrease somewhat.

Stephens Island, with patches of regenerating forest clearly visible


Tuatara tuesday – its not a dinosaur, OK?

September 14, 2010

From today I’ll be starting a semi-regular series of posts about my favourite reptile and #1 study organism, the tuatara.  I want to start by clearing up a misconception that I see repeated time and time again, that tuatara are “New Zealand’s living dinosaur”.

Tuatara are an entirely different lineage of reptiles from the dinosaurs.  Here’s a simplified phylogenetic tree of reptiles to illustrate:

Phylogeny of reptiles, based on that of Hugall et al. 2007 with additional information from the Tree of life (http://tolweb.org/Dinosauria/14883). Dinosaurs, including the lineage that evolved into birds, are in blue.

The closest living relatives of the dinosaurs are the crocodilians (alligators and crocodiles), and birds.  In fact, it is birds that are the “living dinosaurs”, as they evolved from the Theropod dinosaurs, the lineage that includes tyrannosaurs, Velociraptors and Archaeopteryx.  Crocodilians, dinosaurs and birds are collectively known as Archosaurs.

Tuatara are in their own Order, Rhynchocephalia, which is entirely separate from the Archosaurs.  The closest relatives of the Rhynchocephalids are the squamates (lizards and snakes), but they are not particularly close relatives at all, having diverged early in reptilian evolution, around 250 million years ago.  The tuatara is the only remaining species of Rhynchocephalid living today, but back in the time of the dinosaurs (around 65-230 million years ago), Rhynchocephalids were everywhere.  Numerous different species of fossil Rynchocephalid have been found across Europe, Africa and the Americas.   However, Rhynchocephalids appear to have died out everywhere except New Zealand around the same time the dinosaurs went extinct 65 million years ago.  Why they hung on in New Zealand is a mystery, but may have something to do with the apparent lack of competition from mammals.

Modern-day tuatara share a lot of morphological features with some of the earliest Rhynchocephalid fossils.  That, combined with the fact that they are the only living species from this lineage, has earned them the title of “living fossil”.  However, it is premature to say that tuatara are “unevolved” or “unchanged since the dinosaur era”.  For one thing, we don’t actually have any ancestral tuatara fossils  from New Zealand dating back to the dinosaur era for comparison (the earliest tuatara fossil dates to a measly 16 mya), and recent studies have shown that many aspects of their morphology and biology are derived, making them just as “evolved” as any other species (but that’s the subject for another post).

So, although tuatara are the last member of an ancient reptile lineage, and still retain some morphological characteristics of these early reptiles, they are a completely different type of reptile from dinosaurs.  Their ancestors lived alongside the dinosaurs, but so did the ancestors of modern-day turtles, crocodiles, lizards, and snakes.

References:

Hugall AF, Foster R, Lee MSY (2007) Calibration choice, rate smoothing, and the pattern of tetrapod diversification according to the long nuclear gene RAG-1. Systematic Biology 54: 543-563
Jones MEH, Tennyson AJD, Worthy JP, Evans SE, Worthy TH (2009) A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and palaeobiogeography of the tuatara (Sphenodon). Proc. R. Soc. London B 276: 1385-1390.

New Zealand Conservation Week

September 12, 2010

This week (September 12-19th) is New Zealand Conservation Week. There are a huge number of events planned around the country, including weed swaps, planting days, beach clean ups, and talks.  The chickenoreggblog family will be doing its bit by taking to the Darwin’s Barberry seedlings that are threatening to take over the garden here on our windy Karori hillside.

Details are on the Department of Conservation website, so get out there and participate!