"It's a bit of a squeeze"
Bull Ants Feed at Twilight
Bull ants do not feed during all daylight hours. Observation has shown that they feed at twilight. When the sun is brighter for longer, for example in summer or there is no cloud cover, they forage for food later in the day. When the sun is darker, earlier, they search for food sooner in the day. It was believed that all insects fed according to circadian rhythms, but this does not seem to be the case.
Activity in the nest was affected by cloud cover. But outside activity that involves feeding occurs at twilight. Obviously, they are feeding during these short intervals to avoid predators. Most animals that eat ants would be inactive at twilight.
Tests were done at ANU in Canberra. Bull ants were put in containers where diffused light was altered. It was found they only fed when the light was set at a particularly low level. Evolution does take some winding paths. This shows though that evolution develops in a rational way.
Activity in the nest was affected by cloud cover. But outside activity that involves feeding occurs at twilight. Obviously, they are feeding during these short intervals to avoid predators. Most animals that eat ants would be inactive at twilight.
Tests were done at ANU in Canberra. Bull ants were put in containers where diffused light was altered. It was found they only fed when the light was set at a particularly low level. Evolution does take some winding paths. This shows though that evolution develops in a rational way.
Humans Wiped Out Australia's Megafauna
Humans destroy more things in the environment than climate change. This is especially the case in Australia where over the last 50,000 years people have wiped out the county's megafauna. Before Aboriginals arrived flightless birds, large reptiles and giant marsupials lived a carefree existence.
Humans slaughtered the large animals in a very short period of time. More accurate dating of bones shows that megafauna died out abruptly. When the giant creatures were in large numbers there is no evidence of human tools. After the Diprotodon, Australia's largest marsupial, large kangaroos and flightless birds died out stone tools appeared. Accurate dating shows they did not exist at the same time even though they were found together at certain locations. When humans became settled the large animals were gone. The odd thing is that humans and megafauna must have coexisted for at least 5,000 years. But this is a very narrow window to find evidence of both living side by side.
This gives weight to the theory that the arrival of modern Man in the Americas caused the demise of the mammoth. Though there is a problem with the American story. Megafauna "ruled" during the ice age which occurred 12,000 years ago. Its seems that when the ice ages ended life changed for the large animals. The climate was then well and truly against the survival of mammoths, short-faced bears, giant bison and sabor-toothed tigers. Some megafauna, however, continued to survive in Kansas, and Nebraska after the ice age period. The skeleton of a giant beaver has been found dating from 10,000 years ago. So Man could still be the culprit.
Humans slaughtered the large animals in a very short period of time. More accurate dating of bones shows that megafauna died out abruptly. When the giant creatures were in large numbers there is no evidence of human tools. After the Diprotodon, Australia's largest marsupial, large kangaroos and flightless birds died out stone tools appeared. Accurate dating shows they did not exist at the same time even though they were found together at certain locations. When humans became settled the large animals were gone. The odd thing is that humans and megafauna must have coexisted for at least 5,000 years. But this is a very narrow window to find evidence of both living side by side.
This gives weight to the theory that the arrival of modern Man in the Americas caused the demise of the mammoth. Though there is a problem with the American story. Megafauna "ruled" during the ice age which occurred 12,000 years ago. Its seems that when the ice ages ended life changed for the large animals. The climate was then well and truly against the survival of mammoths, short-faced bears, giant bison and sabor-toothed tigers. Some megafauna, however, continued to survive in Kansas, and Nebraska after the ice age period. The skeleton of a giant beaver has been found dating from 10,000 years ago. So Man could still be the culprit.
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