Menu
Science and knowledge
New frog discovered in New York City
Why the 'Man in the Moon' faces Earth
Jilted fruit flies turn to alcohol
Fertilisers behind increase in N2O levels
Early Earth hazy one day, clear the next
Could air pollution be making us fat?
Frog skin protein may help fight superbugs
Electrotherapy dampens brain connections
Satellite images spot early settlements
Chemistry helps sperm find the right egg
Social butterflies find safety in numbers
Ibuprofen reduces altitude sickness: study
Mercury findings raise new questions
Megafauna collapse led to mega changes
New device invisible to magnetic fields
Travelling gnome answers weighty question
Study throws Moon theory up in the air
James Cameron reaches bottom of Pacific
Link builds between extremes and warming
Some chocolate-eaters have lower BMI
Dingoes, devils may be angels in disguise
Barefoot running less energy efficient
Dolphin males share human social network
Recycled spectacles twice that of new: study
Egg size was dinos ultimate undoing
The fact that land-bound dinosaurs laid eggs is what sealed their fate of mass extinction 65 millions of years ago, says scientist.

In a new explanation for mammals' evolutionary victory over dinosaurs, researchers claim a mathematical model has shown that infant size was the clincher.

Given physical limitations to egg size, dinosaurs had comparatively small young. Some came out of the egg weighing as little as two to 10 kilograms, yet had to bulk up to a hefty 30 or 50 tonnes.

Growing up, the youngsters had to compete in several size categories with adults of other animal groups for food, says University of Zurich scientist Marcus Clauss.

This meant that all the small and medium animal size categories supported by the natural environment were "occupied", leaving no room for smaller dinosaur species in which to thrive, according to the findings published in Biology Letters.

"There is a lot of room in the ecosystem for small species, but (in such a scenario) that room is taken up by the young ones of the large species," says Clauss.

"That was not a problem for 150 million years but as soon as something happens that takes away all the large species so that only small species remain, if there are no small species to remain you are gone as a whole group."

The catastrophic event that wiped out all larger life forms some 65 million years ago meant the end for terrestrial dinosaurs.
Mammals best equipped

Scientists disagree on whether the scaly reptiles died out before or after a meteorite smashed into Earth in what is known as the Cretaceous-Tertiary impact, causing billions of tonnes of wind-borne ash and dust to filter out light from the Sun and triggering a "nuclear winter" that cooled the planet and withered vegetation.

Mammals did not have the same limitations in size spread, says Clauss, because their young were not born as comparatively small and did not need to compete with other species for food, instead suckling on their mothers.

This meant there were smaller mammal species able to cope with the new post-catastrophe environment and evolve into new species alongside birds, which are also dinosaurs.

"The question that haunted some people including me is ... why did the mammals survive and why did the dinosaurs not. I think we have a very good answer for that," says Clauss.

The researchers says egg size is constricted by upper limits to the thickness of shells, which have to allow oxygen through to the embryo.

The average forty-tonne titanosaur, the largest type of vertebrate that ever lived, was 2500 times heavier than its newborn. A modern-day elephant mother weighs 22 times more than her calf.

Scientists say all animals with a bodyweight of more than about 10 to 25 kilograms died in the mass extinction event.

Для печати
Astronomers uncover stardust origins
Guns make people seem bigger
Traditional Chinese medicines under scrutiny
Baboons leave scientists spell-bound
Mars Viking robots 'found life'
Nothing helps create pure randomness
Jet lagged bees may help patient recovery
Study calls for regulating salt in fast foods
NASA clears SpaceX for space supply run
Egg size was dinos ultimate undoing
Peripheral vision snaps brain 'video' power
Study raises hopes of cure for baldness
Cosmic rays leave scientists in the dark
Bone-protecting protein discovered
Thylacine DNA reveals lacks of diversity
Aspirin's fat burning mechanism found
Polar bears are no new kids on the block
Calls back evolutionary gender theory
Asteroid impact pushes life underground
Arctic Ocean could be source of methane
Statins don't reduce melanoma risk
Facebook beauty is more than screen deep
Your brain could become your password
One hit of ecstasy 'resets body clock'
Antacid armour key to tetrapod survival
Fathers just as likely to get baby blues
Maths explains left-handed boxer success
Scientist claims to have found G-spot
Menu
Sprawling cities pressure environment
Fossil raindrops reveal early atmosphere
Fossil find reveals steps back in time
Report suggests new formula for Earth
Handprints may give away your height, gender
Monster solar tornadoes discovered
Study reveals why some soccer players dive
Teen brains undergo neural pruning
Martian dark spots reveal heart of glass
Cave holds earliest sign of fire-use
Stress may alter body's immune response
Japanese bees cook enemy in 'bee ball'
Tired locusts hold breath to rest their brains
X-rays shed new light on lung function
Mutant bird flu 'much less lethal'
T-rex had a giant feathered ancestor
Carbon dioxide ended last Ice Age: study
Saving ships from Titanic's fate
Dental x-rays linked to brain tumours
Fire-free farming in pre-Columbian Amazon
Teamwork made humans brainier: study
Drug data should be made public: report
Omega-3 pills may not help heart disease
Pigeons' sixth sense eludes scientists
Visit Statistics
http://google.com/

http://bing.com/

https://gepatit-info.top/

https://serdechnic.com/

https://buy-meds24.com/

https://dverirespekt.ru/

https://www.sribno.net/

https://undergroundcityphoto.com/

https://detskiezabolevaniya.com/

http://grafaman.ru/

http://innoslicon.com/html/product/index.htm

https://yginekologa.com/

https://yes-com.com/

https://www.baikaleminer.com/

https://bitmaein.com/shop

https://www.artdeko.info/

https://aerodizain.com/

http://xn--d1abj0abs9d.in.ua/

http://lider82.ru/

http://sta-grand.ru/

http://snabs.kz/

https://sky-mine.ru/

https://rybalka-opt.ru/

http://snegozaderzhatel.ru/

https://xn--e1aaajzchnkg.ru.com/

http://hit-kino.ru/

http://www.regionshop.biz/

https://xn--80aaafbn2bc2ahdfrfkln6l.xn--p1ai/

https://pp-budpostach.com.ua/

https://vykup-avto-krasnodar.ru/

https://gcup.ru/

https://mega-polis.biz.ua/

http://vanrise.com.ua/

http://infra-e.ru/

https://veterinariya.com/

https://ponosanet.com/

https://cariestop.com/

https://proartrit.com/

https://elonm.ru/

https://nakozhe.com/

https://spinanebolit.com/

http://zameskino.ru/

http://kinoprinc.ru/

http://pospektr.ru/

http://buypillsonline24h.com/

http://komputers-best.ru/

https://komp-pomosch.ru/