If you look different to your close relatives, you may have felt separate from your family. As a child, during particularly stormy fall outs you might have even hoped it was a sign that you were adopted.
As our new research shows, appearances can be deceptive when it comes to family. New DNA technology is shaking up the family trees of many plants and animals.
The primates, to which humans belong, were once thought to be close relatives of bats because of some similarities in our skeletons and brains. However, DNA data now places us in a group that includes rodents (rats and mice) and rabbits. Astonishingly, bats turn out to be more closely related to cows, horses and even rhinoceroses than they are to us.
Scientists in Darwin's time and through most of the 20th century could only work out the branches of the evolutionary tree of life by looking at the structure and appearance of animals and plants. Life forms were grouped according to similarities thought to have evolved together.
About three decades ago, scientists started using DNA data to build "molecular trees". Many of the first trees based on DNA data were at odds with the classical ones. Sloths and anteaters, armadillos, pangolins (scaly anteaters) and aardvarks were once thought to belong together in a group called edentates ("no teeth"), since they share aspects of their anatomy. Molecular trees showed that these traits evolved independently in different branches of the mammal tree. It turns out that aardvarks are more closely related to elephants while pangolins are more closely related to cats and dogs.
Tukuler
multidisciplinary Black Scholar
Member # 19944
posted
Coming together
There is another important line of evidence that was familiar to Darwin and his contemporaries. Darwin noted that animals and plants that appeared to share the closest common ancestry were often found close together geographically. The location of species is another strong indicator they are related: species that live near each other are more likely to share a family tree.
For the first time, our recent paper cross-referenced location, DNA data and appearance for a range of animals and plants. We looked at evolutionary trees based on appearance or on molecules for 48 groups of animals and plants, including bats, dogs, monkeys, lizards and pine trees. Evolutionary trees based on DNA data were two-thirds more likely to match with the location of the species compared with traditional evolution maps. In other words, previous trees showed several species were related based on appearance. Our research showed they were far less likely to live near each other compared to species linked by DNA data.
It may appear that evolution endlessly invents new solutions, almost without limits. But it has fewer tricks up its sleeve than you might think. Animals can look amazingly alike because they have evolved to do a similar job or live in a similar way. Birds, bats and the extinct pterosaurs have, or had, bony wings for flying, but their ancestors all had front legs for walking on the ground instead.
Similar wing shapes and muscles evolved in different groups because the physics of generating thrust and lift in air are always the same. It is much the same with eyes, which may have evolved 40 times in animals, and with only a few basic "designs".
Our eyes are similar to squid's eyes, with a crystalline lens, iris, retina and visual pigments. Squid are more closely related to snails, slugs and clams than us. But many of their mollusc relatives have only the simplest of eyes. Moles evolved as blind, burrowing creatures at least four times, on different continents, on different branches of the mammal tree. The Australian marsupial pouched moles (more closely related to kangaroos), African golden moles (more closely related to aardvarks), African mole rats (rodents) and the Eurasian and North American talpid moles (beloved of gardeners, and more closely related to hedgehogs than these other "moles") all evolved down a similar path.
Tukuler
multidisciplinary Black Scholar
Member # 19944
posted
Evolution's roots
Until the advent of cheap and efficient gene sequencing technology in the 21st century, appearance was usually all evolutionary biologists had to go on.
While Darwin (1859) showed that all life on Earth is related in a single evolutionary tree, he did little to map out its branches. The anatomist Ernst Haeckel (1834-1919) was one of the first people to draw evolutionary trees that tried to show how major groups of life forms are related.
Haeckel's drawings made brilliant observations of living things that influenced art and design in the 19th and 20th centuries. His family trees were based almost entirely on how those organisms looked and developed as embryos. Many of his ideas about evolutionary relationships were held until recently. As it becomes easier and cheaper to obtain and analyse large volumes of molecular data, there will be many more surprises in store.
posted
^^Yes, I learned all this back during my undergrad studies. Morphological features are often times deceiving. For example, there are two species of fig wasps inhabiting the same niche of the same environment (a fig tree) and they look entirely identical, but genetics reveals they are in fact divergent species that can no longer interbreed.
So what of intraspecies variation, specifically humans? We know there are populations who may closely resemble each other physically such as Europeans and Ainu (or Kennewick Man) but genetically are quite distant and the converse-- populations that look very different but are in fact closely related such as in Africa hence the fallacy of 'race'.
Such is tersely explained by writer and skeptical critic Kenan Malik in his 2008 book on race Strange Fruit: Why Both Sides are Wrong in the Race Debate and explained in his article here:
This reminds me, while I do not deny totally the theory of evolution, I do notice certain holes in the theory which fail to explain large jumps in speciation let alone the origin of living cells from non-living organic material.
There is also the little known fact that Charles Darwin was a Freemason and a member of the Invisible College which explains certain beliefs expressed in the entirety of of the title of his book: On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. It was Darwin but more so his colleague Sir Francis Galton who founded modern eugenics including racial eugenics.
Posts: 26239 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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quote:Originally posted by Djehuti: This reminds me, while I do not deny totally the theory of evolution, I do notice certain holes in the theory which fail to explain large jumps in speciation let alone the origin of living cells from non-living organic material.
It's my understanding that Darwin's theory of evolution through natural selection was meant to explain how life changed over generations, not how it originated. I point that out because too many people, most notoriously creationists, seem to equate the theory of evolution (or "Darwinism") with atheistic and naturalistic accounts of how life and the Universe began. Whatever Darwin's own views of religion and the supernatural were, you should know that plenty of religious people have found a way to reconcile his theory of evolution through natural selection with their faith in God. IIRC, the Catholic Church even incorporated it into their doctrine.
As for the "holes" you bring up, I wouldn't say we have all the answers for those questions yet. Scientists have noted a trend of "punctuated equilibrium" which I suspect correlates with what you call "large jumps in speciation", but I don't know if they have an explanation for the trend yet. I believe the origin of living cells from inorganic matter is also still a mystery, although there have been experiments attempting to simulate it by recreating the conditions of prehistoric earth.
That said, you're right that Darwin had some attitudes towards race (as well as sex and gender) that haven't aged well at all. You might be interested in a critique of his views (as related in Descent of Man) by Agustin Fuentes here.
quote:Originally posted by Djehuti: [QB] ^^Yes, I learned all this back during my undergrad studies. Morphological features are often times deceiving. For example, there are two species of fig wasps inhabiting the same niche of the same environment (a fig tree) and they look entirely identical, but genetics reveals they are in fact divergent species that can no longer interbreed.
So what of intraspecies variation, specifically humans? We know there are populations who may closely resemble each other physically such as Europeans and Ainu (or Kennewick Man) but genetically are quite distant and the converse-- populations that look very different but are in fact closely related such as in Africa hence the fallacy of 'race'.
The idea of human races was conceived before genetic analysis It's a phenotypic concept largely If you use the terms "white people" or "black people", these are racial terms
"black skinned" or "white skinned" is not although subjective
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^ Of course notions of 'race' have existed long before Darwin, but it was Darwin and especially Galton who promoted the modern notion of 'race' as genetic unit inherent to all of that unit and its treatment as as a species. This is why during the so-called Age of Exploration and Colonization the British promoted the study and collection of "racial specimens".
To Brandon, evolution like many theories are not perfect but the problem is people especially scientific experts fail to realize that science cannot explain everything or at least science based on technological observations is still limited. The fallacy of relying on science alone when science is flawed or imperfect is known as scientism and is just as bad or dangerous as unchecked religiosity without rationale. In fact scientism has become a religion nowadays. What's more is that many of the scientific theories we take for granted are based not so much on science but older occult (religious) beliefs! As I said, Darwin and Galton like many prominent British scholars were not only Freemasons but members of the Invisible College a mystical organization. The same organization that Isaac Newton was a part of who also developed many of his theories based on ancient religious views i.e. gravity and inertia being euphemisms for Empedocles' divine forces of love and strife. Isaac Newton was also an alchemist who drank mercury.
-------------------- Mahirap gisingin ang nagtutulog-tulugan. Posts: 26239 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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I notice either morphological or molecular the flying lemur is in a separate category from the regular lemur that is a primate. They resemble a combination of squirrel and bat. They can glide down from a tree but not actually fly. They put bats and flying lemurs in a separate category from rodents and primates
Anyway, the human position above as primate
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