(ORDO NEWS) — If you don’t look like your close relatives, you may have felt separated from your family. As a child, during particularly violent fights, you might even hope that this was a sign that you were adopted.
Appearances can be deceiving when it comes to family, as our new research shows. New DNA technology has shaken up the genealogies of many plants and animals.
Primates, which include humans, were once thought to be close relatives of bats due to some similarities between our skeletons and brains.
Now, however, the DNA data puts us in a group that includes rodents (rats and mice) and rabbits. Surprisingly, bats are more closely related to cows, horses, and even rhinos than we are.
Scientists at the time of Darwin and throughout most of the 20th century could only determine the branches of the evolutionary tree of life by studying the structure and appearance of animals and plants. Life forms were grouped by similarity, it was believed that they developed together.
About three decades ago, scientists began using DNA data to build “molecular trees”. Many of the first trees based on DNA data diverged from the classical ones.
It used to be that sloths and anteaters, armadillos, pangolins (scaly anteaters) and arardavrs belonged to the edentates (“toothless”) group, since they have common anatomical features.
Molecular trees have shown that these traits evolved independently in different branches of the mammalian tree. It turned out that aardvarks are closer to elephants, and pangolins are closer to cats and dogs.
There is another important piece of evidence that was familiar to Darwin and his contemporaries. Darwin noticed that animals and plants that have the closest common origin often occur geographically close to each other.
The location of species is another strong indicator of their relationship: species that live near each other are more likely to share a common ancestry.
For the first time in our recent work, data on the location, DNA and appearance of a range of animals and plants were compared. We looked at appearance-based or molecular-based evolutionary trees for 48 groups of animals and plants, including bats, dogs, monkeys, lizards, and pines.
Evolutionary trees based on DNA data were two-thirds more likely to match the location of a species than traditional maps of evolution. In other words, the previous trees showed that several species were related based on appearance.
Our study showed that they are much less likely to live next to each other compared to species related based on DNA data.
It may seem that evolution is endlessly inventing new solutions, with almost no limits. But she has fewer tricks up her sleeve than you might think.
Animals can look remarkably similar because they evolved to do similar jobs or lead similar lifestyles. Birds, bats, and extinct pterosaurs have or had bony wings for flight, but all of their ancestors had forepaws for walking on the ground.
Similar wing shapes and musculature evolved in different groups because the physics of creating thrust and lift in the air is always the same. The same thing happens with the eyes, which may have evolved 40 times in animals and have only a few basic “constructs”.
Our eyes are like squid eyes: lens, iris, retina and visual pigments. Squids are closer relatives of snails, slugs and shellfish than we are. But many of their mollusk relatives have only the simplest eyes.
Moles have evolved as blind, rogue creatures at least four times, on different continents, on different branches of the mammalian tree.
Australian marsupial moles (more closely related to kangaroos), African golden moles (more closely related to aardwarks), African moles (rodents), and Eurasian and North American talpid moles (beloved by gardeners and more closely related to hedgehogs than other “moles”) are all they developed along a similar path.
Origins of evolution
Until the advent of cheap and efficient gene sequencing technology in the 21st century, appearance was usually all that evolutionary biologists relied on.
Although Darwin (1859) showed that all life on Earth was connected by a single evolutionary tree, he did little to outline its branches. The anatomist Ernst Haeckel (1834-1919) was one of the first to draw evolutionary trees that attempted to show how the major groups of life forms were related.
Haeckel’s drawings made brilliant observations of living things that influenced art and design in the 19th and 20th centuries. His bloodlines were based almost entirely on how these organisms looked and developed as embryos. Many of his ideas about evolutionary relationships have persisted until recently.
As it becomes easier and cheaper to acquire and analyze large amounts of molecular data, there are many more surprises in store for us.
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