What Is: Extinction Level Events

A Chronicle of Earth's Biotic Crises and an Assessment of Future Threats
Image Credit: Scientific Frontline

Defining Biotic Catastrophe

The history of life on Earth is a story of breathtaking diversification and innovation, but it is punctuated by chapters of profound crisis. These are the extinction level events—catastrophes of such magnitude that they fundamentally reset the planet's biological clock. Popular imagination often pictures a single, sudden event, like the asteroid that sealed the fate of the dinosaurs. The geological reality, however, is more complex and, in many ways, more instructive for our current era. Understanding these events requires a rigorous scientific framework that moves beyond simple notions of species loss to appreciate the systemic collapse of entire global ecosystems.

A New Study Indicates Forest Regeneration Provides Climate Benefits, but Won’t Offset Fossil Fuels

Forest regrowth after 5 years since agricultural abandonment near Pucallpa, Ucayali, Peru.
Photo Credit: Jorge Vela Alvarado, Universidad Nacional de Ucayali

When farmland is abandoned and allowed to return to nature, forests and grasslands naturally regrow and absorb carbon dioxide from the atmosphere—helping fight climate change. However, a new study in the journal Global Biogeochemical Cycles, led by scientists at Columbia University, reveals an important wrinkle in this story: these regenerating ecosystems also release other greenhouse gases that reduce some of their climate benefits. The good news? Even accounting for these other gases, letting land regenerate naturally still provides important climate benefits compared with keeping it in agriculture.

Lead author Savannah S. Cooley, a research scientist at NASA Ames Research Center and a recent PhD graduate of Columbia’s Ecology, Evolution and Environmental Biology program, and her team of co-authors analyzed data from 115 studies worldwide to understand how forests and grasslands affect the climate through three key greenhouse gases: carbon dioxide, methane and nitrous oxide. While previous research focused mainly on carbon dioxide absorption by growing trees, this study examined a more complete picture.

How origami robots with magnetic muscles could make medicine delivery less invasive and more effective

A crawling robot created with the Miura-Ori origami pattern. The dark areas are covered in a thin magnetic rubber film which allows the robot to move.
Photo Credit: Courtesy of North Carolina State University

A new 3-D printing technique can create paper-thin “magnetic muscles,” which can be applied to origami structures to make them move.

By infusing rubber-like elastomers with materials called ferromagnetic particles, researchers at North Carolina State University 3-D printed a thin magnetic film which can be applied to origami structures. When exposed to magnetism, the films acted as actuators which caused the system to move, without interfering with the origami structure’s motion.

"This type of soft magnet is unique in how little space it takes up," said Xiaomeng Fang, assistant professor in the Wilson College of Textiles and lead author of a paper on the technique.

“Traditionally, magnetic actuators use the kinds of small rigid magnets you might put on your refrigerator. You place those magnets on the surface of the soft robot, and they would make it move,” she said. “With this technique, we can print a thin film which we can place directly onto the important parts of the origami robot without reducing its surface area much.”

Broad-Bayer collaboration leads to drug candidate for a hard-to-treat type of lung cancer

Broad Communications Scientists in the Broad-Bayer oncology alliance have developed a drug candidate, sevabertinib, that could be a new lung cancer treatment.
Illustration Credit: Agnieszka Grosso

An alliance of scientists at the Broad Institute and Bayer Pharmaceuticals have developed a drug candidate, sevabertinib, that could be a new treatment for a group of lung cancer patients who have few options today.

In a new study published in Cancer Discovery, the team described their efforts to develop sevabertinib. They tested the compound in various lung cancer models and showed its potential to treat non-small cell lung cancers that harbor certain mutations in the ERBB2 gene, which encodes the HER2 protein. These mutations occur in 2 to 4 percent of patients with non-small cell lung cancer, or roughly 40,000 to 50,000 people diagnosed globally each year. These patients tend to be women, including those who are younger, have never smoked, and have a poor prognosis. 

The study also reported data from two participants in Bayer’s phase 1/2 clinical trial of the compound. Based on these findings and other data from this ongoing clinical trial, the drug candidate is currently under Priority Review at the FDA, an expedited review of therapies that treat serious conditions. If approved, it would be the first FDA-approved cancer drug based on Broad discoveries, and the first new medicine from the Broad-Bayer oncology research alliance. 

New antivirals could help prevent cold sores by changing cell structures

Pin1 inhibitors suppress HSV-1 replication by inhibiting viral protein synthesis and preventing nucleocapsid egress from the nucleus.
Illustration Credit: Takemasa Sakaguchi/Hiroshima University

A class of antivirals called Pin1 inhibitors could reduce or stop outbreaks of herpes simplex virus 1 (HSV-1), the common infection behind oral herpes, according to new research published in Antiviral Research.

HSV-1 causes sores around the mouth, commonly called cold sores or fever blisters. Most people are infected with HSV-1 in childhood, and between 50% and 90% of people worldwide have HSV-1. After the initial infection, HSV-1 remains in the body and can reactivate throughout a person’s life. While HSV-1 infections are usually mild, they can be serious and even deadly for people with suppressed immune systems. Finding new, more effective antivirals for this common illness is essential. 

Researchers focused on an enzyme called peptidyl-prolyl cis-trans isomerase NIMA-interacting 1, or Pin1, that regulates protein stability, function, and cellular structure. When this enzyme is dysregulated, it can play a role in a variety of conditions, including obesity, cancer, heart failure, and more. Viruses, such as cytomegalovirus (CMV) and SARS-CoV-2, are known to affect Pin1, and Pin1 inhibitors have been developed to reduce the impact of these viruses. 

When Machines Learn to Feel

Changes in heart rate can provide information about physical and emotional well-being. 
Photo Credit: © RUB, Kramer

In addition to linguistic prompts, large language models can also understand, interpret, and adapt their responses to heart frequency data. Dr. Morris Gellisch, previously of Ruhr University Bochum, Germany, and now at University of Zurich, Switzerland, and Boris Burr from Ruhr University Bochum verified this in an experiment. They developed a technical interface through which the physiological data can be transmitted to the language model in real time. The AI can also account for subtle physiological signals such as changes in heart activity. This opens new doors for use in medical and care applications. The work was published in the technical journal Frontiers in Digital Health.

Archaeologists uncover 5,000-year-old ceremonial site in Jordan

Dolmen found at Murayghat in Jordan.
Photo Credit: Susanne Kerner, University of Copenhagen

A research team led by the University of Copenhagen has uncovered a remarkable Early Bronze Age ritual landscape at Murayghat in Jordan. The discovery can shed new light on how ancient communities responded to social and environmental change.

How did ancient cultures respond to crises and the collapse of the established social order? The 5,000-year-old Early Bronze Age site of Murayghat in Jordan, which has been extensively excavated by archaeologists from the University of Copenhagen, may hold an answer.

Murayghat emerged after the decline of the so-called Chalcolithic culture (ca. 4500–3500 BCE), a period known for its domestic settlements, rich symbolic traditions, copper artifacts, and small cultic shrines.  

When healing turns harmful: adrenal support cells tied to cancer origin

Image Credit: Scientific Frontline / AI generated

A new study from Karolinska Institutet, shows that support cells in the adrenal gland can regenerate hormone-producing tissue after birth. The same cells may also act as a starting point for adrenal tumors, offering new insights into cancer development and potential treatment strategies.

“We found that these glial-like cells not only help maintain healthy tissue but, in some paragangliomas, also carry the same tumor-initiating genetic event,” explains Susanne Schlisio, group leader at the Department of Oncology-Pathology and last author of the study. 

“In tumors with germline VHL mutations, subsets of these support cells showed loss of chromosome 3p, the ‘second hit’ leading to VHL inactivation. This suggests they may be the origin of certain tumors,” says Dr. Michael Mints, docent at the same department and co-corresponding author of the study.

In a surprising discovery, scientists find tiny loops in the genomes of dividing cells

MIT experiments have revealed the existence of “microcompartments,” shown in yellow, within the 3D structure of the genome. These compartments are formed by tiny loops that may play a role in gene regulation.
Illustration Credit: Ed Banigan, edited by MIT News
(CC BY-NC-ND 4.0)

Before cells can divide, they first need to replicate all of their chromosomes, so that each of the daughter cells can receive a full set of genetic material. Until now, scientists had believed that as division occurs, the genome loses the distinctive 3D internal structure that it typically forms.

Once division is complete, it was thought, the genome gradually regains that complex, globular structure, which plays an essential role in controlling which genes are turned on in a given cell.

However, a new study from MIT shows that in fact, this picture is not fully accurate. Using a higher-resolution genome mapping technique, the research team discovered that small 3D loops connecting regulatory elements and genes persist in the genome during cell division, or mitosis.

“This study really helps to clarify how we should think about mitosis. In the past, mitosis was thought of as a blank slate, with no transcription and no structure related to gene activity. And we now know that that’s not quite the case,” says Anders Sejr Hansen, an associate professor of biological engineering at MIT. “What we see is that there’s always structure. It never goes away.”

New study finds large fluctuations in sea level occurred throughout the last ice age, a significant shift in understanding of past climate

Photo Credit: Michael Chen

Large changes in global sea level, fueled by fluctuations in ice sheet growth and decay, occurred throughout the last ice age, rather than just toward the end of that period, a study published this week in the journal Science has found.

The findings represent a significant change in researchers’ understanding of how the Pleistocene – the geological period from about 2.6 million to 11,700 years ago and commonly known as the last ice age – developed, said Peter Clark Link is external, a paleoclimatologist at Oregon State University and the study’s lead author.

“This is a paradigm shift in our understanding of the history of the ice age,” said Clark, a university distinguished professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

During the last ice age, Earth experienced cycles of dramatic shifts in global sea level caused by the formation and melting of large ice sheets over northern areas of North America and Eurasia. These changes are recorded in the shell remains of microscopic marine organisms called foraminifera, which are found in ocean sediment and collected by drilling cores, giving scientists an important record of past climate history.