Tag: Evolution

I used to think the lungfish was the halfway species between sea and land animals but I was not aware of the epaulette shark until the possible discovery of a new species of them made the news: Here is a five year old video:

According to the ABC news report they can stay out of water for up to two hours.

I can believe the part where they are said to survive on land by shutting down several of their brain functions. Now that might explain a lot about another, more familiar, two-legged creature that has become a land-dweller!

A most fascinating read is Lewis Dartnell’s Origins: How Earth’s History Shaped Human History.

In his first chapter, he provides an answer to the question: What was it about our environment that selected for the emergence of us, bipedal, somewhat more intelligent than other primates, highly social, etc? More specifically, what was it about the Rift Valley in East Africa that made it the setting for the appearance of our first ancestors?

The first puzzle is why the Rift Valley at all and why that region does not share the dominance of rain forests that are the feature of the other regions in the same latitudes — Amazon, South-East Asia.

Dartnell brings together the wealth of published research into questions like these and identifies the following factors:

1. The crashing of India into Eurasia forcing up the Himalayas. To be more specific, it is the subsequent erosion of the Himalayas — the effects of ice sheets and rain — that has led damp soil to pull carbon dioxide out from the atmosphere, react with it and form calcite that is washed away down to the oceans where it is transformed into shells by sea creatures. Carbon dioxide extraction from the atmosphere has had a cooling effect on the globe. The cooling has resulted in less rainfall and a drier climate.

2. At the same time, and related to the above, moisture is being sucked into the Himalayan and Tibetan region to create the monsoon system over India and South East Asia, but this has meant the pulling of moisture from East Africa.

3. The crashing of Australia into New Guinea led to land rises that blocked off the warm waters that had flowed from the Pacific into the Indian Ocean, allowing colder waters from the North Pacific to take their place.

4. Add 1, 2 and 3 above and we begin to see why rain forests are not to be expected in East Africa.

Next scene: tectonic shifts around East Africa

5. Magma pushed up along the region from the Red Sea through to Kenya and beyond. That caused the overlying crust to slowly split, making huge cliffs either side of a new valley floor that was some half a mile above sea level.

6. The mountains forming on the east side blocked rainfall from the Indian ocean from reaching much of the valley itself. Add that to #4 above.

7. Continue reading “How Earth Created Homo Sapiens”

Well that’s what I was taught by the creationist men of God when I was part of their world. Wings had to work perfectly the first time or what use were they? So went the rhetorical question and we were all shook our heads in disbelief at how foolish people of the world were for thinking otherwise.

But a couple of nights ago I could not resist following the build up to watching David Attenborough’s new program, The Empire of the Ants. The catch line that intrigued me was the promise to show how some ants had learned to cooperate with others who were not genetically related to them. (Others, true to expected form, fought unrelated groups to the death for territorial control.) The whole program was absolutely fascinating (as most of Attenborough’s docos are) but one episode in particular thoroughly amused me. . . .

Queen ants about to fly away to establish a new colony are heavy with fat reserves and swollen ovaries and have sprouted wings just for the new occasion — their maiden flight to mate then start a new colony. They climb to the top of a plant to get some height for a take-off, but often times they make complete fools of themselves trying to make respectable use of their wings. We are shown footage of queen ants starting lift off but quickly tilting backwards or sideways and falling back down to the ground. Why didn’t God give them wings (and the instinctual know-how using them) that worked and got their heavier bodies up and away the first time?

It’s not as if they would need the wings afterwards. Once they had found their new space they had no need for the wings anymore and naturally wanted to get rid of the encumbrances. Again amusing footage showing the poor things struggling to dislodge their “back-packs” with nothing but legs! God lacked the forethought to arrange at least two of those six legs for that purpose. Those queens were obviously struggling with even more difficulty than a child trying to figure out how to dry its back after a bath.

Well I just had to laugh (I even saw the photographs) . . .

I first heard of the custom when living in Singapore. Strippers hired to perform before an image of the deceased as part of the ceremonies pending the actual cremation. I thought the idea was to give the deceased one last good time. Maybe it’s hard to grasp if we’re not familiar with the Chinese custom in crowded Singapore of setting up a marquee or special area for the coffin of the deceased on the property of the apartments where he or she lived, or nearby, with friends and relatives coming to visit over the days prior to the cremation ceremony. Candles, decorations of models of the things the deceased loved in life (paper cars, boats, money…), other religious paraphernalia all around, and lots of chairs and water bottles for the visitors. There would always be someone there to maintain the vigil, even through the night.

And some (by no means all — unless I was protected by the locals from ever finding out) of these spaces, I learned, even arranged for a private striptease dancer to perform before the picture of a male deceased.

And all of that was before the last day when crowds would assemble, with musicians and dancers, to drive the coffin off in a specially decorated truck leading a street procession to the place of cremation. What a send off.

Well, today I was reminded of all of the above with the following news:

China cracks down on funeral strippers hired to entertain mourners, attract larger crowds

Hired to attract crowds! Now that was different from the Singapore custom, that’s for certain. If I can ever remember where I filed it I will dig out the Singapore newspaper photo of the Chinese dancer there definitely facing and performing for the deceased. But in China the image is definitely indicative of a more general entertainment:

Now that’s definitely not what Singapore Chinese modesty was all about. Unless, as I said, I was protected because I was considered to be just another foreigner who would not understand.

What piqued my more serious interest in the story this time, however, was the suggestion that the ceremony might be traced back to “fertility worship”. One last ditch effort to ensure the deceased would still be able to, well… I’m not quite sure what. Anthropologists would be able to explain it, no doubt.

And given the eclectic interests of Vridar, I am further reminded of the Gospel of John. See Novelistic plot and motifs in the Gospel of John where I look at an article by Jo-Ann Brant discussing the way that gospel plays with the idea of a marriage anticipated by Jesus really being his death.

It all seems rather appropriate, I supposed, given that what made death possible (as opposed to evolving like ever dividing cells that go on forever and never die) was sex. Perhaps the story of Adam and Eve and their Fall is all about the way cell death evolved to remove and discard the less good bits from the mix.

H/t Rosa Rubicondior, a scientific research paper discusses experiments indicating that we humans are not the only ones who have an ethic of helping out strangers in need: Bonobos respond prosocially toward members of other groups by Jingzhi Tan, Dan Ariely and Brian Hare. It’s an amazing read. A Bonobo stops doing something that’s “fun” when it sees a complete stranger (another Bonobo from no other community it knows) who is unable to get food and not only stops play, but goes to considerable effort to get the food to that needy stranger. And there’s no reward. It appears to know the commandments of Zeus, Allah, Yahweh and Jesus Christ and obeys them out of unselfish love.

Beware, Humans. If you don’t pull your socks up God will forsake you and go to the Bonobos who are more worthy!

Interesting article by Diana Hayward on yesterday’s ABC Science page:

Algae explosion 650 million years ago is why we’re here today, ANU researchers say

The key section:

That climatic catastrophe was a global thawing of what Professor Brocks calls a “Snowball Earth”.

Fifty million years before the algae began to bloom the Earth’s oceans were frozen.

But a global heating event caused the glaciers to melt and as they did they released nutrients into the ocean.

“This increased phosphate fertiliser in the oceans,” Professor Brocks said.

And when the Earth cooled to more hospitable levels it created perfect conditions for algae to spread.

“It appears this huge release of nutrients after the melting of this snowball Earth event triggered the evolution of this larger algae and replaced bacteria.”

“Algae are incredibly large in comparison to bacteria. And you need large and nutritious organisms at the base of the food webs to create the burst of energy towards higher and bigger organisms,” Professor Brocks said.

So it all started with global warming and the subsequent explosion in algae.

Brought myself up with the latest discoveries on human origins last night with BBC doco The Lost Tribes of Humanity. It told me that everything I had been taught about Neanderthals at school was wrong, and enlightened me on how to pronounce this other type of human I’ve come across in my reading from time to time, the Denosivans, introduced me to the term “hominin”, and backed my wife’s suspicion that I probably do carry around Neanderthal DNA in my genome.

Neanderthals

1. Neanderthals did leave artistic remains. The marks left on rocks were tested for various options such as side-products of cutting other things like skins on the rock surface and the eventual conclusion was that the marks were made as deliberate designs. (I learned they had no art.)
2. Neanderthals adorned their bodies. Remains of certain bones indicate that wings were cut for feathers, not for meat. Feathers in abundance points to body decoration. (That was new.)
3. Neanderthals buried their dead.
4. They were not wiped out by the arrival of Homo Sapiens. The two types of human lived side by side for thousands of years, probably learning from one another.
5. Modern humans interbred with Neanderthals. Most people of non-African origin have some Neanderthal DNA; about 1 to 2 percent on average of their DNA is Neanderthal. (I was taught the two could not interbreed.)
6. The above fact indicates that modern humans interbred with Neanderthals very early in their trek out of Africa — probably when they first met Neanderthals in what today is the Middle East. This scenario would explain why modern humans across the globe contain Neanderthal DNA — with the exception of most Africans.
7. Possibly up to 50% of all the Neanderthal DNA is still extant today, collectively, in modern humans. (We each contain around 1-2% of Neanderthal DNA but we don’t all contain the same DNA bits.)

Denisovans (D’nEESovins)

• Races native to Australia and Papua New Guinea contain up to 5% of the Denisovan genome. Denisovan DNA is also found among the peoples of India, Himalayas and China. Up to 60 to 80% of Denisovan genome may be spread around in modern humans.

“The Hobbit” / Homo floresiensis

I was following the controversy surrounding these bones when they were first discovered in Indonesia and for a time was unsure if we would find we had a new type of human species or modern human inflicted with something like dwarfism. But the jury has apparently long been in by now and they definitely have been classified as a distinct variety of human.

Interestingly their small size was not the effect of being cut off on the island (animals so cut off tend to become smaller, presumably because less resources are therefore required to survive) but they were found to be small before their settlements were cut off by rising seas.

Though they have left remains indicating their human-ness their brains were the size of chimp brains. Sounds bad for a human, perhaps, but then as someone else pointed out recently on another program, we now know from our technological advances that it is not the size of a computer that matters so much as how it is organized. Even “bird-brains” can be very intelligent.

Archaic Africans

This group was new to me. We know of their past existence in Central Africa entirely from DNA samples among people of African descent — beginning in a laboratory in San Francisco of all places. They split off from the earliest human line then connected again some millennia later with the line leading to us.

So we don’t even need to dig up fossils to learn of the existence of other species or tribes of humans.

Interbreeding can have been through a range of activities, including adopting orphaned babies and raiding for mates.

My science fiction fantasy: Will we one day be able to piece together all the different bits of remaining DNA from Neanderthals and Denisovans and Archaic Africans and somehow put them together again the way Humpty was sort of reassembled — not literally in laboratories, god forbid, but on paper/digital files — and get some idea what those other branches of hominin were like compared with our pre-mongrel ancestors?

Okay, it’s a bit old, but awards have just been bestowed upon the scientists involved so it’s worth noting once again. Some fascinating science news by science reporter Natalie Whiting:

‘Eureka moment’ research into ocean selenium levels asks: Did mountains control evolution of humans?

Their research has shown that almost every major growth period or extinction in the Earth’s history correlates with a change in the amount of the trace element selenium in the ocean.

When there are high levels of selenium, there is growth; when levels fall, there are extinctions. . . .

. . .

“These three mass extinction events are put down to things like global anoxia — a lack of oxygen in the oceans causing extinctions, or cooling events, like ice age events.

“But none of these events or causes in themselves are total explanations for the widespread extinctions both in the oceans and on land in some instances.

“So our explanation of the trace element depauperation (poor development) in the oceans is a very good example of something that covers all the bases and actually gives a better explanation for some of these events.”

Then there’s header that I like:

A twist on Darwin’s theory: Did man evolve from the mountains?

The research has provided strong evidence that it is the movement of tectonic plates which releases trace elements, like selenium, into the ocean.

“So we’ve added a new dimension where you might say that really it’s plate tectonics which controls evolution. Because, indirectly, plate tectonics controls the chemistry of the ocean, and the chemistry of the ocean has a big control on evolutionary pathways,” Professor Large explained.

“That’s why I often say to people basically man came from the mountains. It’s mountain building, and the erosion of all those nutrients into the ocean, that controlled man’s evolution.”

Further, a discussion on The Conversation:

Plate tectonics may have driven the evolution of life on Earth

What on earth was God thinking?

When is a female a female? And when is a male a male? These are the questions that scientists continue to ponder after the latest research on an Australian lizard that reverses its sex when exposed to high incubation temperatures.

The study shows central bearded dragons (Pogona vitticeps) that are born with male chromosomes, but can lay eggs, have other strange characteristics.

Super-female bearded dragons are ‘more male than male’

“A bearded dragon can have male sex chromosomes but be a functioning female. Yet it can be more male-like in the way it looks, in its temperature and in its behaviour. They are more male-like than the actual males,” Professor Shine said.