Study: Crocodile evolution rebooted by Ice Age glaciations - The Daily Guardian
Connect with us

Lifestyle & Entertainment

Study: Crocodile evolution rebooted by Ice Age glaciations

Published

on

Ottawa [Canada], February 17 (ANI): As per a study driven by McGill University, researchers have discovered impacts of Ice Age sea-level changes in the genomes of Caribbean and Pacific crocodiles in Panama.
Crocodiles are resilient animals from a lineage that has survived for over 200 million years. Skilled swimmers, crocodiles can travel long distances and live in freshwater to marine environments. But they can’t roam far overland. American crocodiles (Crocodylus acutus) are found in the Caribbean and Pacific coasts of the Neotropics but they arrived in the Pacific before Panama existed, according to new research.
Over 3 million years ago, the formation of the Isthmus of Panama altered global ocean circulation, connecting North and South America and establishing the Caribbean Sea. This resulted in widespread mixing of species on the continent and separation in the seas.
On land, mammals from North America such as mammoths, saber-toothed cats, horses, and camels invaded South America, and strange mammals like giant ground sloths, armadillos, and opossums from South America invaded North America. This event is known as the Great American Interchange, and the opposite happened in the seas, where new species of corals, clams, and fishes evolved in the separated Pacific and Caribbean waters.
The question a group of McGill and Panamanian researchers asked was: how distant are the Pacific and Caribbean populations from each other and do they match the geological record? Researchers have long suspected that American crocodiles living on the Pacific coast should have diverged genetically enough from Caribbean populations to become unique species.
“We assumed we would detect significant genetic differences between Pacific and Caribbean crocodile populations that were isolated for the past 3 million years,” thought Jose Avila-Cervantes, a recent Ph.D. graduate of McGill University under the supervision of Professor Hans Larsson.
To test this, Avila-Cervantes captured and took blood samples of crocodiles from several populations living on both coasts of Panama. Back at McGill University, he sequenced their genomes to look for small variations in their DNA.
He used the genetic differences to estimate how much evolutionary divergence and gene flow existed between populations. With this information, the team found that Pacific and Caribbean crocodile populations have been separated for only about 100,000 years.
“This time of separation is a far cry from the 3 million years we were expecting,” said Professor Larsson, Director of the Redpath Museum at McGill. “But it did match the last interglacial period of the Ice Age.”
Glacial and interglacial cycles in the Ice Age mark periods of peak polar glaciations separated by relatively warm times. These warm times caused sea levels to rise over 100 meters globally compared to present-day levels. Using the record of Ice Age sea levels, Avila-Cervantes was able to reconstruct what Panama would have looked like during these peak cold and warm periods of the Ice Age.
“It surprised us to see that during the warm interglacial periods, most of Panama was underwater with the coasts separated by brackish lagoons, small rivers, and thin stretches of land,” said Avila-Cervantes. “These are the reasons why we think crocodiles were able to pass from coast to coast freely and explain why their oldest genetic signature of separation coincides with this time.”
A second younger signature of genetic separation is timed to about 20,000 years ago and coincides with the last glaciation cycle that they found made Panama about twice as wide as it is today, and probably a good barrier for these crocodiles. “This is one of the first studies to implicate Ice Age glaciation-interglaciation cycles with the evolution of a tropical organism.”
Yet the researchers discovered there is some genetic divergence between the populations on each coast despite the frequent inter-glaciations, and this diversity is at risk due to habitat destruction from human development. “It was difficult to find any population living on the Pacific coast near the Panama Canal,” said Avila-Cervantes.
One of the best-preserved populations is in the middle of the Panama Canal on the Barro Colorado Island Nature Monument. “Preserving the population around this island may be our best chance to preserve the unique genetic signatures of Panamanian American crocodiles,” said Professor Larsson.
“Our study not only highlights the resilience of crocodiles to ancient climate changes and their great capacity to survive large geological events but also their vulnerability to our voracious need to modify their environments.” (ANI)

The Daily Guardian is now on Telegram. Click here to join our channel (@thedailyguardian) and stay updated with the latest headlines.

For the latest news Download The Daily Guardian App.

Lifestyle & Entertainment

FORMAT OF PRIYANKA’S NEW SHOW, THE ACTIVIST, CHANGED

Published

on

WASHINGTON: After facing huge backlash, Priyanka Chopra Jonas’ new series ‘The Activist’ is now being reconfigured. As per Variety, the makers have shifted its five-episode format to a one-time documentary special. Many social media users slammed the show for being tone-deaf and insensitive. CBS and producing partners Global Citizen and Live Nation issued this statement, “The Activist’ was designed to show a wide audience, the passion, long hours, and ingenuity that activists put into changing the world, hopefully inspiring others. But it has become apparent the format of the show distracts from the vital work these incredible activists do in their communities every day. The push for global change is not a competition and requires a global effort. So we are changing the format to remove the competitive element and reimagining the concept into a primetime documentary special (air date to be announced), it will showcase the tireless work of six activists and the impact they have advocating for causes they deeply believe in. Each activist will be awarded a cash grant for the organisation of their choice.”

Continue Reading

Lifestyle & Entertainment

CHRIS PRATT TO BANKROLL ‘STRANDED ASSET’

Published

on

WASHINGTON: Hollywood star Chris Pratt is all set to produce the action-comedy ‘Stranded Asset’, which is written by Sam Richardson and Jen D’Angelo.

According to Variety, the upcoming film reunites the trio after their successful collaboration on ‘The Tomorrow War’, which Pratt executive produced and starred in alongside Richardson. D’Angelo was the on-set writer for the sci-fi feature. Pratt will produce ‘Stranded Asset’ through his Indivisible Productions banner. Sam Richardson will also star in the film. More details of the project have not been announced yet. 

Continue Reading

Lifestyle & Entertainment

TABU TO STAR IN VISHAL BHARDWAJ’S FILM ‘KHUFIYA’

Published

on

MUMBAI: Tabu is all set to work with ace filmmaker Vishal Bhardwaj again in ‘Khufiya’, which will release on Netflix.

Based on an espionage novel ‘Escape to Nowhere’ by Amar Bhushan, ‘Khufiya’ is a a spy thriller. Excited to reunite with Bhardwaj, Tabu shared on Instagram, “Expect nothing but sheer thrill. Excited to announce my re-uniting with @vishalrbhardwaj for #Khufiya. Coming very soon on @netflix_in. Khufiya is a one of a kind project, extremely close to my heart and I am excited to be a part of this gripping spy thriller. As always, it’s a delight working with VB (Vishal Bhardwaj) again, and feels like homecoming.” ‘Khufiya’ is a story about Krishna Mehra, an R&AW operative who is assigned to track down India’s defence secrets. Bhardwaj is trying to create an edgy espionage film that contrasts the slow burn of intelligence and surveillance work with deep-rooted emotional conflicts. 

Continue Reading

Lifestyle & Entertainment

BIG B MISSES PRE-PANDEMIC ‘SUNDAY DARSHAN’ WITH FANS

Published

on

MUMBAI: Waving to fans gathered outside his Jalsa residence used to be megastar Amitabh Bachchan’s Sunday morning routine. However, due to the coronavirus pandemic, Big B stopped the ritual. Taking to Instagram on Wednesday, Amitabh took a stroll down memory lane and expressed his sadness on not being able to meet his well-wishers. “Thank you well wisher .. yes .. when will those Sunday well wishers at Jalsa return,” he wrote. Alongside the note, Big B posted an image of himself surrounded by imaginary fans and he was seen embracing them as the human connection has gotten a bit lost due to the COVID-19 pandemic.

Meanwhile, on the work front, Amitabh is busy hosting the new season of ‘Kaun Banega Crorepati’. Speaking of films, he will be seen in ‘Good Bye’, ‘Brahmastra’, and ‘The Intern’ remake.

Continue Reading

Lifestyle & Entertainment

JACQUELINE GETS CANDID WITH ARJUN ON ‘BAK BAK WITH BABA’

Published

on

MUMBAI: Arjun Kapoor recently invited Jacqueline Fernandez on his digital chat show ‘Bak Bak with Baba’. Arjun questioned Jacqueline on crushes, food, and how she tackles trolls on social media. Talking about her first crush, Jacqueline said, “There was somebody in school but I can’t name him. I also had a huge crush on Leonardo DiCaprio after watching ‘Romeo and Juliet’ and ‘Titanic’ and Ricardo from ‘Backstreet Boys’.” Arjun asked her “How important is food to you?” She shared, “though I feel it’s nice to celebrate with food as everyone enjoys it, there was a phase in my 20’s when I did turn to food and that was late at night. I lived alone so it was like cake, ice cream, anything crispy. I did have a terrible relationship with food and then went starving for a week and that’s really bad. So, now it’s about knowing that I don’t need to turn to it, tomorrow is another day and we will get through it.”

Continue Reading

Lifestyle & Entertainment

ANANYA, SIDDHANT & ADARSH BAG NEW FILM, ‘KHO GAYE HUM KAHAN’

Published

on

MUMBAI: Ananya Panday, Siddhant Chaturvedi, and Adarsh Gourav will be seen sharing screen space in Excel Entertainment and Tiger Baby’s new film ‘Kho Gaye Hum Kahan’.

Young, fresh and relevant, ‘Kho Gaye Hum Kahan’ is a ‘digital’ age story of three friends in the city of Bombay. The film is written by Zoya Akhtar, Arjun Varain Singh and Reema Kagti, produced by Zoya Akhtar, Reema Kagti, Ritesh Sidhwani and Farhan Akhtar. The film will be the directorial debut of Arjun Varain Singh featuring the young and talented Siddhant Chaturvedi, Ananya Panday and Adarsh Gourav. While Siddhant became a household name (MC Sher) after the success of Zoya Akhtar’s ‘Gully Boy’, fans are excited to see the talented actor share screen space with Ananya. It would also be interesting to see Adarsh in the mix, whose last breakout performance in the Netflix film ‘The White Tiger’ garnered immense praise and appreciation.

On the occasion of writer-producer Reema Kagti’s birthday, Excel Entertainment & Tiger Baby have launched the poster and video—announcing the release of their next theatrical project, ‘Kho Gaye Hum Kahan’ in 2023.

Continue Reading

Trending