Showing posts with label evolved. Show all posts
Showing posts with label evolved. Show all posts

First-NIght-Effect Means Little Sleep at New Hotel

SAnthropology: we have evolved to be on guard on the first night when sleeping in a new place.
Man is still a hunter. We may live in cities and believe we are advanced but our genes have evolved to survive in the wild outdoors beneath the starlit night sky. If we move into a new environment getting a good night's sleep on the first night is a problem. Our brain is "on-guard" against unknown dangers.
Primitive man sleeps
This phenomenon is in all animals. One hemisphere of the brain will sleep while the other remains on sentry duty. This "first-night-effect" is permanent. There is no cure because it isn't an illness. After the first night the brain adapts, records the new environment and deems it to be safe.

Tests show that the left hemisphere sleeps lighter in a new situation. Slow-wave activity is weaker than the right hemisphere. Furthermore, the default-mode network which involves mind wandering is more active. This indicates that the brain is checking the environment. Sleeping test subjects were played some normal and some unusual sounds. The left hemisphere became even more alert when it heard unusual sounds or even loud sounds. After the first night the brain became "normalized" then no such activity was observed.
 Anthropolgy by Ty Buchanan 
 Australian Blog
            Australian Blog   Adventure Australia

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Australopithecus africanus were much like humans. They had evolved to use their hands to do intricate thing. It would have been possible for them to turn a key or hold a hammer. Coming down from the trees "caused" manipulatory advancement. The most useful attributes spread to more of their number due to longer survival and breeding capability.

While anthropologists are not sure that they used the advanced abilities, it is highly probable that they did otherwise the traits would not have become dominant. This pushes tool use way, way back to 3 million years ago.

How do scientists know that Australopithecus had complex skills? Trabeculae which is inside bones in the hands shows how hands were used. Humans, for example use the fingers and thumb region more than chimpanzees. Our friendly relations mainly use their fingers.

The supposition that tool use began millions of years ago was only theory: now it is proven.  Culture must have been passed on to offspring as well.  Tool use is a skill that must be taught.  Humans are capable of learning all their lives.  Chimpanzees can learn how to break nuts using a rock when they are young.  If they watch this being done when they are adults they never learn how to do it.
Science by Ty Buchanan
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     Australian Blog                         

Kiwi Came from Australia

Three years ago a fossil was found at st Bathams in New Zealand. The record books now have to be rewritten. It seems the fossil is an ancestor of the Kiwi and it indicates that it was related to the Australian emu. This undermines the premise that the kiwi is a solely New Zealand bird. After all it is the national symbol.

You see, the emu relative could fly and it flew to New Zealand. It was a tiny bird compared to the kiwi. The enormous egg that kiwis lay evolved. It was not "handed-down" by the giant Moa. Eggs began to get larger in birds during the Miocene.

The theory that the kiwi originated in Australia was commonly held before this fossil find. It was believed to have got to New Zealand when the country was joined to Australia on Gondwanaland, but his view has been put to rest.

Most New Zealand birds got bigger over time. This was not unusual. The kiwi evolved from the earlier tiny ancestor. Discovery of this 20 million year old fossil was pure luck. It is the oldest fossil ever found in New Zealand.
Conservation by Ty Buchanan
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     Australian Blog                         

New Classification System for Bird Species

Birds are the most diverse creatures on Earth.  Not only have they changed into different species on large continents, they have also adapted specifically to environments on islands.

A new classification system is in the form of a circle with increasing diversity as one moves out in time from the center.  different types of birds are correctly located on the figure covering a period of 50 million years.

There is not one specific ancestor.  "Base" species take the form  of a circle of time moving out from the center and new kinds of birds branch off directly to the outer edge.  Fast evolving birds are in red; slower ones are drawn in blue.

Significantly birds such as woodpeckers often split into new species, while hornbills, for example, did not.  There was more diversification in the Western Hemisphere.  Furthermore, species did not proliferate in the tropics because the climate remained stable there over a long period.
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