Tag Archives: Bristol

New research explains why crocodiles are relatively unchanged since dinosaur times

If you look around, you’ll see all sorts of dinosaur descendants, although we call them birds nowadays. But if you want to truly see a dinosaur-like creature, just like it would have roamed the Jurassic age 200 million years ago, just find a crocodile. While some of the species have died out (previous ancestors also consisted of giants as big as the dinosaurs, plant-eaters, fast runners, and serpentine forms that lived in the sea), a lot of what you see now is what you got then.

In new research published in the journal Nature Communications Biology, scientists from University of Bristol explain how crocodiles follow a pattern of evolution known as ‘punctuated equilibrium’.

Crocodiles have many traits which gave them the ability to survive the past 200 million years (Image: Pixabay)

If it ain’t broke, don’t fix it

The rate of crocodile evolution is generally slow, but occasionally they evolve more quickly because the environment has changed and they need to adapt. Specifically, the research suggests that the crocs’ evolution speeds up when the climate is warmer (which it was in the age of the dinosaurs more than it is, today which could explain the different varieties that emerged then), and that their body size increases.

The secret to their slow aging is the limited diversity of crocs and their apparent lack of evolution. It seems the crocodiles arrived at a body plan that was very efficient and versatile enough that they didn’t need to change it in order to survive. They have the ability to thrive in or out of water — they can stay under water for up to an hour — and are able to live in complete darkness. They are also very robust, meaning they can survive horrible injuries.

Believe it or not, it actually isn’t that uncommon for a crocodile to lose a leg and then go on to live another 70 and 100 years.

So while the rest of their dinosaur contemporaries were done in by the asteroid which pancaked itself into the Gulf of Mexico 66 million years ago, crocodiles’ traits — such as the ability to draw energy from the sun, something others couldn’t do — allowed then to continue on life’s journey.

“Our analysis used a machine learning algorithm to estimate rates of evolution,” said lead author Max Stockdale. “Evolutionary rate is the amount of change that has taken place over a given amount of time, which we can work out by comparing measurements from fossils and taking into account how old they are.”

The crocodiles have had a much greater diversity of forms in the past. Examples include fast runners, digging and burrowing forms, herbivores, and ocean-going species. Image credits: University of Bristol.

For the study, the team measured body size — which is important because it interacts with how fast animals grow — how much food the crocodiles needed, the number of their populations, and how likely they were to become extinct.

“It is fascinating to see how intricate a relationship exists between the earth and the living things we share it with,” said Stockdale. “The crocodiles landed upon a lifestyle that was versatile enough to adapt to the enormous environmental changes that have taken place since the dinosaurs were around.”

Now, the next step for the researchers is to see why some crocodiles thrived through the millions of years, while others didn’t.

The study has been published in Nature Communications Biology.

Environmental concerns stop expansion of British airport

In what has been hailed as a pivotal victory for environmental protection, city councilors in Bristol, UK, have voted against plans to expand the city’s airport, citing environmental concerns.

Expansion work is already underway at the Bristol airport — but even further expansion was rejected.

Environment vs Expansion

Bristol is a fairly large city, with a population of around half a million people. It’s serviced by an airport seven miles away, with a capacity of 7 million people / year. For many, that’s not enough.

The airport was given permission to expand from 7 to 10 million passengers, something which is expected to be completed by 2021. But there were plans to further increase the airport to 12 million passengers — and here, things took an unexpected turn.

Thousands of people publicly objected to the expansion, with environmental activists organizing several symbolic protests against this move. The opposition to expansion plans also included Bristol’s vibrant artistic scene, which includes the likes of Massive Attack and Banksy.

The arguments supporting this expansion are straightforward: some people would like to travel from Bristol to destinations that aren’t currently served. They need to drive to other airports. Building an expansion would reduce this problem and provide jobs and profits to the municipality.

The arguments against the expansion are also clear. The expansion would cause more people to fly, contributing to the climate emergency, and causing localized pollution (leading to an increase in people suffering from conditions such as asthma). Furthermore, the expansion would harm local wildlife — in particular, colonies of bats and birds located in the area. The negative environmental impact, many argued, outweighs the economic one.

Will Bristol set an important precedent? Image credits: Robert Cutts.

It’s already an old tale: on one hand, you have those who want economic growth and increased comfort, and on the other hand, the people fighting for the environment.

Except, this time, the environment won.

After a four-hour meeting, Bristol city council voted against the airport expansion, 18-7. Don Davies, the leader of the council, said:

“What the committee has considered is that the detrimental effect of the expansion of the airport on this area and the wider impact on the environment outweighs the narrower benefits to airport expansion.”

Councillor John Ley-Morgan emphasized that climate change played a major role in this decision:

“How can we achieve our ambition for carbon neutrality by 2030 if we approve this decision?”

Spokespeople for the airport expressed their disappointment with the result of the vote, but for scientists and most of the city’s population, this was a victory for civil society.

Adrian Gibbs, an environmental consultant, told The Guardian that we would need to plant 4 million trees every single year to offset the expansion. Sarah Warren, cabinet member for the climate emergency in the municipality, also added that the expansion is incompatible with the global environmental crisis. For environmental activists, the vote was vindication after months of protests.

This is not the end of the process. The decision can be appealed or the expansion can be modified, after which it might be approved. But it could represent an important turning point.

Air travel is one of the areas for which we don’t really have a sustainable plan — and it’s growing at an impressive rate. Many cities all around the world are considering airport expansions, and the environmental impact of these expansions is significant.

Bristol Airport will still have a capacity of 10 million passengers — which is remarkable for a city of 0.5 million people. However, airport officials say they have responded to the climate emergency and revealed a plan to make the airport “carbon neutral” by 2025. They’ve already taken some steps, such as increasing the use of electric vehicles, shifting to renewable energy and increasing the cost of its drop-off parking as this is the “least sustainable way” to get to the airport.

But when it comes to the planes themselves (and the local environmental impact of the airport), there is still little leverage to offset the damage.

It remains to be seen whether Bristol has set a landmark precedent or this will just be an exception — for now, at least, there is a moment to rejoice for environmentalists.