Scoop CIS2 Animals
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Scoop CIS2 Animals
West Valley College Spring 2013
Curated by Waael Zahriya
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Rescooped by Waael Zahriya from World Environment Nature News
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Elephants really do grieve like us: They shed tears and even try to 'bury' their dead - a leading wildlife film-maker reveals how the animals are like us

Elephants really do grieve like us: They shed tears and even try to 'bury' their dead - a leading wildlife film-maker reveals how the animals are like us | Scoop CIS2 Animals | Scoop.it
Elephant emotions seem so like our own, so heartbreakingly close to human sorrow and grief, writes JAMES HONEYBORNE, producer of BBC1's Africa series.

Via Maria Nunzia @Varvera
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Rescooped by Waael Zahriya from Amazing Science
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Peto's paradox: Why do larger animals such as whales or elephants get fewer cancers than humans?

Peto's paradox: Why do larger animals such as whales or elephants get fewer cancers than humans? | Scoop CIS2 Animals | Scoop.it

If every living cell had an equal chance of becoming cancerous, whales and elephants should have a greater risk of developing cancer than do humans or mice. But across species, the occurrence of cancer does not show a correlation with body mass. According to a new model, the paradox could be explained if animals were striking a balance between reducing cancer risk and other priorities, such as maximising the number of offspring.

 

The lack of correlation between body mass and cancer risk is known as Peto’s paradox, after epidemiologist Richard Peto of Oxford University in the UK, who noted it in the 1970s. Evolutionary biologists think that it results from larger animals using protective mechanisms that many smaller animals do not.

 

In an attempt to identify how greater body mass might foster such mechanisms, evolutionary biologist Benjamin Roche at the Institute of Research for Development in Montpellier, France, and his colleagues created a theoretical model to simulate which of 100 possible genetic-mutation strategies would become most prevalent over 4,000 generations.

 

The model included two gene types: proto-oncogenes, which can cause normal cells to become cancerous, and tumour-suppressor genes, which repair cellular damage that could otherwise lead to cancer. For carcinogenesis to occur, the team assumed that proto-oncogenes must be activated and tumour-suppressor genes must be rendered inactive.

 

“We found that tumour-suppressor genes and proto-oncogenes react differently along a gradient of body masses,” says Roche. “Their evolutionary dynamics are linked.” Proto-oncogene activation decreased steadily with increasing body mass, the team found.

 


Via Dr. Stefan Gruenwald
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