modern science shows how we have done so much wrong

If you look different from your close relatives, you may have felt separated from your family. As a child, during particularly severe breakdowns, you may have even hoped that this was a sign that you were adopted.

As our new research shows, looks can be deceptive when it comes to family. New DNA technology is shaking the family trees of many plants and animals.

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 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 in Darwin’s time and for most of the 20th century were able to develop the branches of the evolutionary tree of life only by examining the structure and appearance of animals and plants. Life forms are grouped according to similarities that are thought to have evolved together.

About three decades ago, scientists began using DNA data to build “molecular trees.” Many of the first trees based on DNA data contradicted the classical ones. Sloths and anteaters, armadillos, pangolins (scaly anteaters) and anteaters were once thought to belong together in a group called toothless (“toothless”) because they share aspects of their anatomy. Molecular trees show that these traits develop independently in different branches of the mammalian tree. It turns out that pipe-heads are more closely related to elephants, while pangolins are more closely related to cats and dogs.

Molecular phylogenies show that mammals as diverse in appearance as ants, manatees, elephant shrews, and elephants are truly close cousins.

Gathering

There is another important line of evidence that was familiar to Darwin and his contemporaries. Darwin notes that animals and plants that seem to share the closest common origins are often geographically close together. The location of species is another strong indicator that they are related: species that live next to each other are more likely to share a family tree.

For the first time, our recent paper recommended location, DNA data, and appearance for a number of animals and plants. We looked at evolutionary trees based on appearance or molecules for 48 groups of animals and plants, including bats, dogs, monkeys, lizards, and pine trees. Evolution trees based on DNA data are two-thirds more likely to match the location of a species than traditional evolution maps. In other words, previous trees have shown that several species are related based on appearance. Our study found that they are much less likely to live close to each other than species associated with DNA data.

It may seem that evolution is endlessly inventing new solutions, almost without limitations. But there are fewer tricks up your sleeve than you think. Animals can look amazingly the same because they evolved to do a similar job or live a similar way. Birds, bats, and extinct pterosaurs have or have had bony wings to fly, but all of their ancestors had front legs to walk the earth.

The color wheels and the key show where the members of each order are located geographically. The molecular tree has these colors grouped better than the morphological tree, which shows a closer agreement of the molecules with biogeography. The figure is from Oyston et al. (2022)
The author is provided

Similar forms of wings and muscles develop in different groups, as the physics of generating traction and lifting in the air is always the same. It’s almost 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 eyes, with crystal lenses, iris, retina and visual pigments. Squid are more closely related to snails, snails and mussels than we are. But many of their mollusk relatives have only the simplest eyes.

Squid and fish have actually been separated by more than half a billion years of evolution.
Flickr, CC BY

Moles have evolved as blind, burrowing creatures at least four times, on different continents, on different branches of the mammal tree. Australian marsupial moles (more closely related to kangaroos), African golden moles (more closely related to dead rats), African moles (rodents) and Eurasian and North American moles (loved by gardeners and more closely related to hedgehogs than others). “Moles”) have all evolved in a similar way.

The roots of evolution

Until the advent of cheap and efficient gene sequencing technology in the 21st century, appearance was usually all that evolutionary biologists had to pursue.

While Darwin (1859) showed that all life on Earth is connected in one evolutionary tree, he did little to draw its branches. The anatomist Ernst Haeckel (1834-1919) was one of the first people to draw evolutionary trees, trying to show how the main groups of life forms are connected.

Illustrations by the German zoologist Ernst Haeckel (here groups of mosses)
Pixaby, CC BY

Haeckel’s paintings made brilliant observations of living beings that influenced art and design in the 19th and 20th centuries. Its family trees are based almost entirely on how these organisms look and develop as embryos. Many of his ideas about evolutionary relationships have been maintained until recently. As it becomes easier and cheaper to obtain and analyze large volumes of molecular data, there will be many more surprises.

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