Earth Wise

A look at our changing environment.

You are here: Home / Archives for evolution

evolution

Can birds outfly climate change?

By Leave a Comment

As global temperatures continue to rise and ecosystems shift, animals are left with limited options. They must either adjust to the changing conditions in their habitats or relocate to cooler environments. For many species, neither choice is easy – or sometimes even possible.

Ecologists had long assumed birds were among the most adaptable species in a warming world simply because they can fly to higher altitudes or towards global poles. But a new study by researchers from Yale University found that even birds are struggling to stay ahead of rising global temperatures.

The study, which was recently published in the journal Nature Ecology and Evolution, analyzed 20 years of data from 406 bird species across North America. They found that while most birds did shift their ranges northward – by about 40 to 50 miles on average during the summer – the changes weren’t enough to keep up with the rapid pace of climate change.

Birds still experienced significant warming in their new areas when compared with temperatures in their original home range.  In fact, warming was about 1.35 degrees Celsius more in summer, and a striking 3.7 degrees more in winter. And some species, especially those with limited flight ranges or specific habitat needs, like the cactus wren, didn’t move at all.

Highly mobile birds like the blue-winged warbler did better, avoiding nearly two degrees of warming by traveling more than 100 miles north. But even they couldn’t completely dodge the heat.

The findings raise serious concerns about whether less mobile species can survive in a warming world, and underscores the urgent need to better understand and manage those most vulnerable to climate-driven extinction.

**********

Web Links

Even birds can’t outfly climate change

Photo, posted March 1, 2023, courtesy of Henry via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Species and climate change

By Leave a Comment

Temperature extremes on Earth currently range from a low of -129°F to a high of 134°F.  But these climatic limits have changed throughout history.  In fact, during the last interglacial period 130,000 years ago, temperatures were warmer, resembling what we are projected to experience at the end of this century.

Species that evolved during such periods may possess pre-adaptations that could help them tolerate upcoming changes to the climate.  This factor is often overlooked by traditional statistical models predicting species’ responses to climate change.

But a new model, developed by researchers from Ifremer in France and Lausanne University in Switzerland, has taken this oversight into account, and reassessed the proportion of terrestrial and marine species threatened with extinction by climate change. 

In the study, which was recently published in the journal Nature Ecology and Evolution, the research team applied its model to nearly 25,000 terrestrial and marine species from around the world.  The researchers discovered that 49% of these species live in climate niches near the current climatic limits, and 86% could potentially extend beyond these limits. 

The most surprising result concerns tropical regions. While forecasts from traditional models estimate that the diversity of terrestrial species in tropical areas could decrease by 54% between now and 2041-2060, the new model predicts a more moderate decline of 39%.

The findings confirm the importance of taking urgent measures to mitigate climate change and its impact on biodiversity.

**********

Web Links

Some species may better tolerate climate change than expected

Photo, posted October 23, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Giant Tortoise Is Not Extinct | Earth Wise

By Leave a Comment

The Galapagos Islands are famous for their tortoises, among many other things. A few million years ago, some giant tortoises from South America were somehow carried across hundreds of miles of ocean to the islands – perhaps on driftwood during storms.  Tortoises don’t swim, so any that made to an island could only breed with others on that same island.   The result was rapid evolution of tortoise species in the Galapagos.  Today, there are 14 different species of giant tortoises there.

Centuries ago, tortoise populations in the Galapagos were decimated by European sailors who hunted them for food.   The giant reptiles could be kept alive on ships with little food or water, so they became a great source of meat.

On the island of Fernandina, there was a species of Galapagos tortoise known as the “fantastic giant tortoise.”  Only a single one of these was ever found and that was in 1906.  It ended up being preserved as a museum specimen.

In 2019, a female tortoise living on Fernandina was located and genome sequencing has only recently been successfully completed for that living specimen and the century-old one in the museum which compared them to sequences of the other 13 species of Galapagos tortoise.  That analysis showed that the two were indeed the same species and are distinct from all the others.

The female tortoise, who has been named Fernanda, now resides at the Galapagos National Park Tortoise Center, which is a rescue and breeding facility.  She is well over 50 years old.  Recent tracks and scat on Fernandina Island provide evidence that there may still be others of her kind.  The experts are trying to do what they can to keep the species alive.

**********

Web Links

‘Fantastic giant tortoise,’ believed extinct, confirmed alive in the Galápagos

Photo, posted January 1, 2019, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plastic-Eating Bugs | Earth Wise

By Leave a Comment

27-year-old Miley Cyrus and 30-year-old Liam Hemsworth divorced exactly one year ago, but still continue to remember each other quite often in conversations with reporters. Recently, Miley indulged in nostalgia once again. During a recording Miley Cyrus boyfriend list of the podcast Barstool Call Her Daddy, the singer said that her ex-husband was her first man. It happened almost 10 years before they got married. I didn’t have that with men until I was 16, but I ended up marrying this guy,

According to a new study, microbes in oceans and soils around the world are evolving to eat plastic.  The study by Chalmers University in Sweden was published recently in the journal Microbial Ecology.

The study is the first large-scale assessment of the plastic-degrading potential of bacteria.  There are 95 microbial enzymes already known to degrade plastic. 

The researchers looked for similar enzymes in environmental DNA samples taken from bacteria from 236 different locations around the world. They found that one in four of the organisms analyzed carried suitable enzymes.  Overall, they found many thousands of new enzymes.

The explosion of plastic production in the past 70 years has given microbes time to evolve to make use of plastic.  About 12,000 new enzymes were found in ocean samples and 18,000 in soil samples.  Nearly 60% of the new enzymes did not fit into any known enzyme classes, suggesting that these molecules degrade plastics in ways that were previously unknown.  The large number of enzymes in such a wide range of habitats is an indication of the scale of the problem of plastics in the environment.

The first bacterium that eats plastic was discovered in a Japanese waste dump in 2016.  Scientists tweaked that microbe in 2018 and managed to create an enzyme that was even better at breaking down plastic bottles.

The next step in research is to test the most promising enzyme candidates in the laboratory to investigate their properties and see how effective they can be in plastic degradation.  The hope is to be able to engineer microbial communities with targeted degrading functions for specific polymer types.

**********

Web Links

Bugs across globe are evolving to eat plastic, study finds

Photo, posted June 19, 2013, courtesy of Alan Levine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Assisting Evolution | Earth Wise

By Leave a Comment

As plants and animals around the world grapple with climate change, invasive species, disease, and other threats, conservationists grapple with the issue of what it means to protect what is natural and how far to go to prevent extinctions.

Australia is where many of these issues have risen to the forefront.  Imported mammals – particularly cats and foxes – have decimated many of Australia’s indigenous marsupials.  Much of the focus for decades has been on killing off the invaders and cordoning off protected animals.  In recent years, however, there have been efforts to expose prey animals to limited numbers of predators to develop prey populations that are better equipped to survive among predators.  Getting rid of all the predators is not realistic.  Saving species may require helping them to adapt.

On the Great Barrier Reef, where half its coral populations have perished because of rising water temperatures, scientists are breeding corals that are more heat tolerant.  They are even considering the use of gene editing technology to “assist evolution” in developing corals that can survive in a changing world.

At SUNY College of Environmental Science and Forestry in Syracuse, New York, researchers have produced a genetically modified American chestnut tree that is resistant to chestnut blight, the fungal pathogen that killed off nearly every chestnut tree in North America in the early 20th century.

The idea of conservation is to protect what is natural in our world.  However, at a time when there are unprecedented threats to so many species, the distinction between what is natural and what is artificial may no longer provide a sound guide to what should be done to protect life on earth.

**********

Web Links

Assisting Evolution: How Far Should We Go to Help Species Adapt?

Photo, posted November, 2000, courtesy of Bernard Dupont via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Why Have Crocodiles Changed So Little Over Time? | Earth Wise

By Leave a Comment

Crocodiles today look very similar to ones from the Jurassic period some 200 million years ago.  In fact, there are very few species of crocodilians alive today – approximately two dozen to be exact.  Many other species have achieved a diversity of many thousands of species in the same amount of time. 

During prehistoric times, many more types of crocodiles roamed the earth, including some as big as dinosaurs and other serpentine forms that lived in the sea.  

According to findings by scientists at the University of Bristol in the U.K., a stop-start pattern of evolution could explain why crocodiles have changed so little over time. In the study, which was recently published in the journal Nature Communications Biology, researchers describe how crocodiles follow a pattern of evolution known as “punctuated equilibrium.”  In other words, crocodiles’ rate of evolution is generally slow, but occasionally picks up because the environment has changed.     

According to the research team, this slow rate of evolution is how crocodile diversity became so limited.  It appears crocodiles arrived at a body that was efficient and versatile.  They didn’t need to continue to change in order to survive.

This efficiency and versatility could be an explanation for why crocodiles survived the meteor impact that wiped out the dinosaurs.  Since crocodiles can’t control their body temperature and rely on the environment for warmth, they generally fare better in warm conditions.  During the age of dinosaurs, the climate was warmer than it is today, which could explain why crocodile diversity was higher.  

The scientists next step is to try to figure out why some prehistoric crocodiles died out while others did not. 

**********

Web Links

Why crocodiles have changed so little since the age of the dinosaurs

Photo, posted December 26, 2012, courtesy of Nicholas Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Infertility

By Leave a Comment

Many of us are all too familiar with the effects of climate change.  Our changing climate, as a result of our actions, is leading to rising global temperatures, biodiversity loss, ocean acidification, wildfires, more weather extremes like floods and droughts. But a lesser known effect of climate change could lead to frightening consequences: infertility.

According to researchers at the University of Liverpool, rising temperatures could make some species sterile and lead them to succumb to the effects of climate change far earlier than currently thought. Their work was recently published in the journal Trends in Ecology and Evolution, and it was produced in collaboration with scientists from the University of Leeds, University of Melbourne, and Stockholm University.

Biologists and conservationists are trying to predict where species will be lost due to climate change so that suitable reserves can be established in other locations.  But the problem is that most data on when temperature will make an area unlivable for a species is based on its ‘critical thermal limit’ or CTL.  This is the temperature at which a species would collapse, stop moving, or die. 

The authors of the article fear that the impact of climate change on species survival is being underestimated.  Because rather than zeroing in on lethal temperatures, the scientists argue the focus should be on the temperatures at which organisms can no longer breed.  Extensive plant and animal data suggest organisms lose fertility at a lower temperature than their CTL.

The scientists have proposed a new fertility-based metric to gauge how organisms function as temperatures climb: Thermal Fertility Limit or TFL.  Understanding when a species will cease to reproduce will certainly help conservation measures. 

**********

Web Links

Climate change and infertility — a ticking time bomb?

Photo, posted August 11, 2013, courtesy of Mike Lewinski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mammals Can’t Seem To Evolve Fast Enough

By Leave a Comment

Our planet has been through five upheavals over the past 450 million years.  During each one, the environment on earth changed so dramatically that most plant and animal species became extinct.  After each of these mass extinction events, evolution slowly filled the gaps in the environment with new species. 

[Read more…] about Mammals Can’t Seem To Evolve Fast Enough

Wikipedia: Especially Unreliable for Politically Controversial Science Topics

By

wikipedia

Wikipedia is world’s most popular online encyclopedia, the sixth most visited website in America, and a source most students rely on. But, according to a recent study, Wikipedia entries on politically controversial science topics can be especially unreliable.

[Read more…] about Wikipedia: Especially Unreliable for Politically Controversial Science Topics

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)