Principles of Animal Physiology - ppt video online download

Principles of Animal Physiology - ppt video online download: TODAY’S SCHEDULE Course Description Unifying themes in physiology

Welcome

profit margin.

161

The diversity

“For my crew, farming has 

The sixth mass extinction is happening faster than expected. Scientists say it's our fault

Adapted From CNN news

Amur leopards are now critically endangered.

By Ivana Kottasová, CNN

Updated 2220 GMT (0620 HKT) June 1, 2020

Meet the women racing to save a species from extinction 03:41

(CNN)The sixth mass extinction is not a worry for the future. It's happening now, much faster than previously expected, and it's entirely our fault, according to a study published Monday.

Bumblebees are going extinct because of the climate crisis, but there are easy ways to help

Humans have already wiped out hundreds of species and pushed many more to the brink of extinction through wildlife trade, pollution, habitat loss and the use of toxic substances. But the findings published in the scientific journal Proceedings of the National Academy of Sciences (PNAS) show that the rate at which species are dying out has accelerated in recent decades.

Gerardo Ceballos González, a professor of ecology at the National Autonomous University of Mexico and one of the authors of the study, said approximately 173 species went extinct between 2001 and 2014.

"173 species is 25 times more extinct species than you would expect under the normal, background, extinction rate," he told CNN in an email. He and his team found that in the past 100 years, more than 400 vertebrate species went extinct. In the normal course of evolution, such extinctions would have taken up to 10,000 years, they said.

Orangutans are being wiped out as their habitat continues to disappear.

Mass extinctions are just as severe as their name suggests. There have been five mass extinction events in the Earth's history, each wiping out between 70% and 95% of the species of plants, animals and microorganisms. The most recent, 66 million years ago, saw dinosaurs disappear.

The past events were caused by catastrophic alterations of the environment, including massive volcanic eruptions or collision with an asteroid. The sixth mass extinction -- the one happening now -- is different: Scientists say it's caused by humans.

"It is entirely our fault," Ceballos González said.

Extinction breeds extinctions

While life on Earth has bounced back after each of these events, it took millions of years to restore the number of species.

"Even though only an estimated 2% of all of the species that ever lived are alive today, the absolute number of species is greater now than ever before," the scientists said. "It was into such a biologically diverse world that we humans evolved, and such a world that we are destroying."

Ceballos González and his colleagues said many of the species that are on the brink of extinction are concentrated in the same regions being decimated by human impacts.

Amur leopards are now critically endangered.

When one species in the ecosystem disappears, it erodes the entire ecosystem and pushes other species toward annihilation. The researchers use amphibians as an example of this phenomena. Hundreds of species of frogs and toads are suffering population declines and extinctions because of the chytrid fungus disease, which is sometimes spread into new areas by humans. Climate change is likely making the issue worse.

This interdependency of different species is bad news for humans, too.

Vanishing: The Earth's 6th mass extinction

"When humanity exterminates populations and species of other creatures, it is sawing off the limb on which it is sitting, destroying working parts of our own life-support system," said Paul Ehrlich, a well known Stanford professor who wrote the controversial 1968 book "The Population Bomb" and is a co-author of the new study.

The researchers also said the current coronavirus crisis shows how the recklessness with which people treat the natural world can backfire badly. Many of the species that are endangered or at the brink of extinction are being decimated by wildlife trade.

"We believe that the recent coronavirus outbreak is linked to wildlife trade and consumption in China," they said. "The ban on wildlife trade imposed by the Chinese government could be a major conservation measure for many species on the brink, if imposed properly."

A lab in a remote Namibian city is saving the cheetah from extinction

The researchers said this data highlights the urgency with which the world needs to act.

Later this year, the UN Convention on Biological Diversity is expected to set new global goals to combat the ongoing biodiversity crisis in the coming decades.

At a 2010 summit in Japan, the United Nations set similar targets. But the world failed to meet most of those 2020 goals and now faces unprecedented extinction rates, threatened ecosystems and severe consequences for human survival.

• 
  

Pangolins may have incubated the novel coronavirus, gene study shows

Live TV 

By Maggie Fox

Updated 5:16 AM EDT, Sat May 30, 2020

(CNN)A deep dive into the genetics of the novel coronavirus shows it seems to have spent some time infecting both bats and pangolins before it jumped into humans, researchers said Friday.

But they said it's too soon to blame pangolins for the pandemic and say a third species of animal may have played host to the virus before it spilled over to people.

What is clear is that the coronavirus has swapped genes repeatedly with similar strains infecting bats, pangolins and a possible third species, a team of researchers from Duke University, Los Alamos National Laboratory and elsewhere reported in the journal Science Advances.

A white-bellied pangolin rescued from local animal traffickers at the Uganda Wildlife Authority office in Kampala, Uganda, on April 9, 2020.

What's also clear is that people need to reduce contact with wild animals that can transmit new infections, the researchers concluded.

The team analyzed 43 complete genomes from three strains of coronaviruses that infect bats and pangolins and that resemble the new Covid-19 virus.

"In our study, we demonstrated that indeed SARS-CoV-2 has a rich evolutionary history that included a reshuffling of genetic material between bat and pangolin coronavirus before it acquired its ability to jump to humans," said Elena Giorgi, a staff scientist at Los Alamos National Laboratory who worked on the study.

How did coronavirus break out? Theories abound as researchers race to solve genetic detective story

But their findings may let pangolins off the hook. The animals, also known as scaly anteaters, are sold as food in many countries, including China, and have been a prime suspect as a possible source of the pandemic.

"The currently sampled pangolin coronaviruses are too divergent from SARS-CoV-2 to be its recent progenitors," the researchers wrote.

Whether the mixing and matching between bat viruses and pangolin viruses was enough to change the virus into a form that now easily infects humans remains unclear, the researchers said.

"It is also possible that other not yet identified hosts (can be) infected with coronaviruses that can jump to human populations through cross-species transmission," the researchers wrote. "If the new SARS-CoV-2 strain did not cause widespread infections in its natural or intermediate hosts, such a strain may never be identified."

But people are setting themselves up to be infected with new viruses via "wet markets" where many different species of live animals are caged and sold, and by moving deeper into forests where animals live, the researchers said.

"While the direct reservoir of SARS-CoV-2 is still being sought, one thing is clear: reducing or eliminating direct human contact with wild animals is critical to preventing new coronavirus zoonosis in the future," they concluded.

View on CNN

---

© 2020 Mak bioscar Broadcasting System, Inc. All Rights Reserved.

Terms of Use | Privacy Policy | AdChoices