>O2 HUB >>>Why Men and women look more alike than ever before?

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Men and women look more alike than ever before, scientists claim

By Daniel Bates

• Women’s facial structure has become noticeably larger

They say that men are from Mars and women are from Venus.

But when it comes to their faces at least, the two sexes are more similar than you might think.

Researchers looked at skulls of men and women dating back to the 16th century and found that over time they have grown alike.

The facial structure of women in particular has changed and become noticeably larger than their older counterparts.

Come together: Researchers looked at skulls of men and women dating back to the 16th century and found that over time they have grown alike

Experts said it was not to do with women evolving to look more like their men, but that better diet and environmental factors had caused the changes.

They examined more than 200 skulls dating between the 16th and 20th centuries from Spain and around 50 skulls from 20th century Portugal to come to their conclusions.

Having such a wide spread of samples was important to the team from North Carolina State University as it showed them how the changes happened over a long period of time.

They found that not only were men and women more alike, but that the Spanish and Portuguese sample were alike too, suggesting that standards developed for one country could be applied for both.

‘Applying 20th century standards to historical remains could be misleading, since sex differences can change over time’

The team focused in on the differences between men and women because it could ‘help us establish the sex of the remains based on their craniofacial features,’ said lead researcher Dr Ann Ross from the North Carolina university department of anthropology.

‘Improving our understanding of the craniofacial features of regional groups can help us learn more from skeletal remains, or even help us identify an individual based on his or her remains,’ she said.

Being able to carry this out is particularly important when an incomplete skeleton is found, she added.

‘This has applications for characterising older remains. Applying 20th century standards to historical remains could be misleading, since sex differences can change over time – as we showed in this study.’

In addition to academic use, the research could be useful in criminal investigations as investigators will be able to tell a man from a woman more easily.

More…

• Egyptian mummies who lived 3,500 years ago ‘had clogged arteries despite healthier lifestyle’
• Lost for 2,000 years… Could this be the first portrait of Jesus?

Related articles

• Facial Structure of Men and Women Has Become More Similar Over Time, North Carolina State University Study (biospace.com)
• Spanish female faces becoming bigger (cosmiclog.msnbc.msn.com)
• Decreasing sexual dimorphism in Iberian peninsula (dienekes.blogspot.com)

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>O2 HUB >>> So that’s why dinosaurs were so bad-tempered?

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So that’s why dinosaurs were bad-tempered… scientists reveal they were plagued by lice

By David Derbyshire

• Study of insect DNA shows that lice evolved more than 65million years ago

No wonder dinosaurs were so bad-tempered. For scientists have discovered that the prehistoric giants were plagued by lice.
A new study of insect DNA has shown that lice evolved more than 65million years ago, at a time when dinosaurs still ruled the Earth.
The research also suggests that mammals and birds began to diversify into the vast range of different species seen today far earlier in prehistory than was previously thought.

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A 44million-year-old louse fossil (left) and a modern version of the parasite (right) that infests aquatic birds. Scientists believe lice may have fed off the blood of feathered dinosaurs

Dr Kevin Johnson, of the University of Illinois, said: ‘Our analysis suggests that both bird and mammal lice began to diversify before the mass extinction of dinosaurs.
‘And given how widespread lice are on birds, in particular, and also to some extent on mammals, they probably existed on a wide variety of hosts in the past, possibly including dinosaurs.’
The researchers created an evolutionary family tree for lice using DNA from 69 different lineages.

Because changes in DNA accumulate over the millennia, the changes can also be used to create a time-line of the evolution of a related group of animals.

Dr Vincent Smith, a co-author of the study published in Biology Letters who works at the Natural History Museum, London, said: ‘Lice are like living fossils.
‘The record of our past is written in these parasites, and by reconstructing their evolutionary history we can use lice as markers to investigate the evolutionary history of their hosts.’
It was once thought that there were relatively few different species of birds and mammals while the dinosaurs were alive.

Itching for a fight: Could lice have made dinosaurs more aggressive?

It was only after the giant reptiles died out 65 million years ago that birds and mammals went through a period of rapid diversification – filling the niches in the seas, air and land left by the dinosaurs.
The new study suggests birds and mammals had begun to diversify long before the dinosaurs went extinct.
‘Ducks do different things from owls, which do different things from parrots, for example,’ said Dr Johnson.
‘I was thought that after the dinosaurs went extinct that’s when these birds or mammals diversified into these different niches.
‘But based on the evidence from lice, the radiation of birds and mammals was already under way before the dinosaurs went extinct.’
Many scientists believe that birds are the descendants of feathered dinosaurs.
Dr Johnson added: ‘So maybe birds just inherited their lice from dinosaurs.’

Related articles

• Dinosaurs were plagued by lice, scientists reveal (dailymail.co.uk)
• Dinosaurs probably had lice: Study (news.bioscholar.com)
• Did Feathered Dinos Spread Lice? (news.sciencemag.org)

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