r/Science_India

Comebacks for wild tigers, tuna and sea turtles prove nature loss can be reversed, scientists say
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Comebacks for wild tigers, tuna and sea turtles prove nature loss can be reversed, scientists say

Conservation comebacks for wild tigers, tuna and green sea turtles prove that global nature loss can be reversed, scientists have said. But a report warns food production must be the next “positive tipping point” if the world is to avert biodiversity collapse.

The World Wildlife Fund (WWF) analysed nearly 36,000 animal populations and more than 5,000 species, producing the largest ever database of vertebrate wildlife. Scientists found populations had declined by an average of 73% since 1970, showing that “nature continues to be degraded at an alarming scale”, with “no sign of losses slowing”.

Nature loss is no longer just an environmental challenge but a direct threat to the global economy, the report says, noting that about half of global GDP – roughly $58tn (£44tn) in 2023 – depends on nature and its ecosystem services. The authors write that species collapse now poses an “existential threat to economic stability, geopolitical security and human wellbeing”.

Animal populations were found to be falling most sharply in tropical, biodiversity-rich regions, while trends in northern temperate parts of the world appeared much gentler.

In Latin America and the Caribbean, land and freshwater wildlife populations fell by an average of 95% between 1970 and 2022, while the equivalent declines were 80% in Africa and 23% in Europe and Central Asia.

https://livingplanet.panda.org/en-IN/

https://www.worldwildlife.org/about/wwf-annual-report/

theguardian.com
u/VCardBGone — 7 days ago
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How pond algae led to a Nobel prize and a new way to study the brain

Scientists who worked out how to control brain cells with light have won this year’s Nobel prize in physiology or medicine. Karl Deisseroth, Peter Hegemann and Georg Nagel were honoured for their research into “light-gated ion channels and optogenetics”.

Peter Hegemann, at Humboldt University of Berlin, and Georg Nagel, at the University of Würzburg, wanted to understand how a tiny, single-celled alga called Chlamydomonas senses light. Light-sensing is not unique to animals with eyes: organisms throughout the living world use light to detect their surroundings and respond to changes in their environment. Even single-cell organisms have proteins that respond to light. These proteins are used to move towards or away from light, to generate energy and to respond to the various demands of a 24-hour day.

Hegemann and Nagel discovered that Chlamydomonas has a beautifully ingenious mechanism of light detection that relies on a single protein called channelrhodopsin.

Channelrhodopsin is built into the outer membrane of the algal cell. Part of the protein faces the water outside the cell and part faces the inside. The protein also contains a small molecule called retinaldehyde, which is able to absorb light.

When light hits the retinaldehyde inside channelrhodopsin, it changes shape. This makes the channelrhodopsin protein change shape too. That change opens a tiny passage through the cell membrane. Positively charged particles, including sodium, can then flow from the water outside the alga into the cell. This movement of charged particles sends a signal inside the alga that helps it swim.

How fantastic to have solved such an interesting biological question, but why the Nobel prize in physiology or medicine? The answer lies in the way nerve cells work. Nerve cells use the movement of charged particles (called “ions”) across their membranes to control their activity. When positively charged particles flow into a nerve cell, they can make it more active.

The researchers realised that if they could put channelrhodopsin into nerve cells, they might be able to switch those cells on simply by shining a light on them. That is exactly what Hegemann, Nagel and the third Nobel-prize winner, Karl Deisseroth, a psychiatrist and bioengineer at Stanford University in California, went on to do.

https://pubmed.ncbi.nlm.nih.gov/14615590/

https://www.nature.com/articles/nature11028

https://www.nature.com/articles/s41591-021-01351-4

https://pmc.ncbi.nlm.nih.gov/articles/PMC6941740/

https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2017.00663/full

https://www.nobelprize.org/prizes/medicine/2026/press-release/

theconversation.com
u/VCardBGone — 9 days ago