Tag Archives: convergent evolution

A pitcher plant and its deadly insides. Credit: Wikimedia Commons.

Carnivorous plants all over the world used convergent evolution to start eating flesh

A pitcher plant and its deadly insides. Credit: Wikimedia Commons.

A pitcher plant and its deadly insides. Credit: Wikimedia Commons.

Typically, animals are the ones that eat plants but there are instances where this goes the other way around. Carnivorous plants are not only a thorn in some vegan’s life philosophy — they’ve been bugging scientists since the time of Darwin. And for good reason, too. What did it take for carnivorous plants such as the pitcher plant to evolve the ability to derive some of their nutrients from flesh? Well, researchers from University at Buffalo might have finally found out how carnivorous plants evolved.

The researchers analyzed the pathways necessary for a carnivorous plant to evolve, particularly in the pitcher plant. The pitcher plant doesn’t have ‘jaws’ like the famous Venus flytrap, immortalized by bad B movies and Sunday morning cartoons, but that doesn’t make it any less deadly. To attract unsuspecting prey, the pitcher plant has a cup-shaped leaf which looks like a normal flower plant. The sides, however, are slippery and at the very center and a gooey liquid traps flies, bees, and other insects. The same liquid breaks down the insects’ exoskeleton turning them into dinner.

Take a look at the pitcher plant in action.

Initially, the researchers focused on the Australian pitcher plant (Cephalotus follicularis). They first sequenced the carnivorous plant’s DNA, then looked for genes that became activated in each of the plant’s two types of leaves — one is a plain leaf that does photosynthesis and the other variety is the death trap. This is how they found a group of genes that seem to turn on only in the pitcher leaf.

The researchers also took samples of fluid from inside the plant’s traps to analyze the stew of digestive enzymes and other proteins and compared them to fluid samples from the unrelated American and Asian pitcher plant species. They also looked at digestive juices in another carnivorous plant, a sundew, which has leaves with sticky little hairs that trap insects like flypaper.

Despite all of these plants are unrelated and evolved independently, they all use the same enzyme to digest prey. What’s striking is that the same genes from noncarnivorous ancestors have been recruited for carnivorous purposes. Namely, proteins originally involved in protecting the plants against diseases and other stressors eventually turned into digestive enzymes. This ability likely appeared as a means for the plants to cope with nutrient-poor environments. Trapping and digesting animals can be indispensable in this situation.

“Analysis of digestive fluid proteins from C. follicularis and three other carnivorous plants with independent carnivorous origins revealed repeated co-options of stress-responsive protein lineages coupled with convergent amino acid substitutions to acquire digestive physiology,” the researchers wrote in the study published in the journal Science.

“These results imply constraints on the available routes to evolve plant carnivory.”

The present findings are a perfect example of so-called convergent evolution, the process by which unrelated or distantly related organisms evolve similar body forms, coloration, organs, and adaptations. For instance, another good example of convergent evolution are bats … and dolphins. Both evolved the same ability to produce, receive, and process ultrasound waves independently.

“It suggests that there are only limited pathways for becoming a carnivorous plant,” says University at Buffalo biologist Victor A. Albert. “These plants have a genetic tool kit, and they’re trying to come up with an answer to the problem of how to become carnivorous. And in the end, they all come up with the same solution.”

Turkey Sized Vegetarian T-Rex Discovered

A seven year old has discovered the fossil of a turkey-sized dinosaur that roamed South America over 140 million years ago. The tiny dinosaur was related to T-Rex, but had few similarities to it; aside for its size, the dinosaur was a vegetarian, munching on plants instead of terrorizing other creatures.

Chilesaurus diegosuarezi grew up to ten feet long Photo: Reuters

At the end of the Jurassic period, the Earth was very different from what it is today. Average temperatures were a whopping 3 degrees Celsius higher than today, there was virtually no frozen landmass, and of course, dinosaurs ruled the planet. But while most dinosaurs were huge and terrifying Chilesaurus diegosuarezi was nothing of sorts.

It had short arms and hands with two fingers, like T-Rex, but feet that resembled long-necked dinosaurs. It could grow up to ten feet, but the discovered specimen was about as big as a turkey. It was part of the same group as Velociraptor and Tyrannosaurus, from which modern birds evolved, but it’s just strange.

“Chilesaurus is so unexpected, so drastically different than anything else we’ve seen before. It’s an anatomical Frankenstein,” says Lindsay Zanno of the North Carolina Museum of Natural Sciences in Raleigh.

Photo: Reuters

The species really riddled paleontologists, who have rarely seen such a hybrid and enigmatic dinosaur. So strange was the dinosaur that initially, scientists believed they were dealing with several different species.

“It’s like a T. rex that’s been shrunk but not shrunk equally,” says Pete Makovicky, an associate curator and dinosaur specialist at The Field Museum in Chicago, who was not involved in the new find. “This animal would’ve looked more silly than fearful … more similar to an ostrich than to T. rex.”

The fossil was actually discovered 11 years ago, when Diego Suarez was only 7 and he was accompanying his geologist parents on an expedition, and the little boy playing actually discovered the dinosaur, who was named in his honor – a remarkable case of beginner’s luck.

“Out of nowhere, two small things appeared. … They were fossils,” Suarez says by email. He ran to show his mother. His parents, he says, “were amazed. You (can) imagine it was, to them, like wining the lottery.” The family sent the fossils to dinosaur specialists in Argentina.

Diego Suarez has a passion for fossils. (Photo: Manuel Suarez)

In terms of evolutionary significance, Chilesaurus seems to throw a curveball. Its ancestors were meat eaters, its living relatives were meat eaters, but it ate plants. It had vertebrae and front limbs like T-Rex and velociraptor, but its feet, ankle and some of its pelvis looked like they belonged to a completely different branch of plant-eating animals. In a way, it’s like a platypus – a creature that embodies distinctive traits from entirely different species.

Martin Eczurra, a PhD student at Birmingham University said:

“Chilesaurus can be considered a ‘platypus’ dinosaur because different parts of its body resemble those of other dinosaur groups due to mosaic convergent evolution. In this process a region or regions of an organism resemble others of unrelated species because of a similar mode of life and evolutionary pressures.”

It might also provide some insight into evolution itself.

“Chilesaurus provides a good example of how evolution works in deep time and it is one of the most interesting cases of convergent evolution documented in the history of life. It comes as false relationship evidence may arise because of cases of convergent evolution – such as that present in Chilesaurus.”

Journal Reference: Fernando E. Novas et al. An enigmatic plant-eating theropod from the Late Jurassic period of Chile. Naturedoi:10.1038/nature14307

(c) askabiologist.asu.edu/

Convergent evolution in bats and dolphins driven by same genes

It’s amazing how two different animals from two completely different environments evolve some identical physical features. Take bats and dolphins for instance. Both of them use a complex system that produces, receives and process ultrasonic sound waves in order to identify visually hidden objects, track down prey or navigate through obstacles better – typically this is referred to as echolocation, a natural sonar. The evolution of similar traits in different species, is known as convergent evolution, and  according to new research led by scientists at Queen Mary University of London and published in Nature this week, evolution at a genetic level is also shared during this process.

To see the extent to which convergent evolution involves the same genes, the researchers proceeded to undertake the most complex and thorough genome-wide surveys of its type. As such, the genomes of some 22 mammals were analyzed, each sequence being compared the other. This included bats and bottlenose dolphins – two species that both use the same form of echolocation, but which have evolved it independently.

This was no easy task, however. To perform the analysis, the team had to sift through millions of letters of genetic code using a computer program developed to calculate the probability of convergent changes occurring by chance, so they could reliably identify ‘odd-man-out’ genes. They used a supercomputer at Queen Mary’s School of Physics and Astronomy (GridPP High Throughput Cluster) to carry out the survey.

(c)  askabiologist.asu.edu/

(c) askabiologist.asu.edu/

Did you know that the scientists that developed the sonar and radar navigation systems used by the military got their idea from studying bat echolocation? Just like bat echolocation, sonar uses sound waves to navigate and determine the location of objects like submarines and ships. Only sonar is used underwater, while bats echolocate in the open air. Radar uses electromagnetic waves to determine the location of objects like planes and ships. Like bat echolocation, radar is also used on open air.

To their surprise, the researchers didn’t find one, two or even dozens of identical genetic changes, but over 200! Consistent with an involvement in echolocation, signs of convergence among bats and the bottlenose dolphin were seen in many genes previously implicated in hearing or deafness.

“We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing,” said Dr Joe Parker, from Queen Mary’s School of Biological and Chemical Sciences and first author on the paper.

Dr. Georgia Tsagkogeorga, who undertook the assembly of the new genome data for this study, added: “We found that molecular signals of convergence were widespread, and were seen in many genes across the genome. It greatly adds to our understanding of genome evolution.”

Group leader, Dr Stephen Rossiter, said: “These results could be the tip of the iceberg. As the genomes of more species are sequenced and studied, we may well see other striking cases of convergent adaptations being driven by identical genetic changes.”

Joe Parker, Georgia Tsagkogeorga, James A. Cotton, Yuan Liu, Paolo Provero, Elia Stupka, Stephen J. Rossiter.Genome-wide signatures of convergent evolution in echolocating mammalsNature, 2013; DOI:10.1038/nature12511

Convergent evolution: when two kids show up with the same costumes

Cyanide is nasty. I don’t care if you’re a venomous snake, an elephant or Charlie Sheen, cyanide is something you don’t want, which makes it an excellent defense mechanism. Lotus corniculatus, commonly known as the bird’s-foot trefoil, a plant common throughout Europe, Asia and Africa has evolved so that it’s leaves have a cyanide reservoir, to keep away unwanted pests. If you come across this plant however, there’s a good chance that you will also come across the caterpillars of the burnet moth, which also contain a highly toxic dose of cyanide.

The two poisons are absolutely identical chemically, and it goes even further: they are produced in exactly the same way. But the two species developed this ability in two completely different ways, by successive tweaking of genes. The discovery, made by Niels Bjerg Jensen at the University of Copenhagen, is among the best examples for convergent evolution – the process in which two of nature’s children appear at life’s party wearing the same clothes, but bought from different genetic stores.

This example may not seem spectacular at a first glance (even though it is), but convergent evolution is often remarkable. For example, a good example of it is bats and whales, who evolved the same sonar ability; another one is shrews and lizards, which developed the same venom. But believe it or not, this example is the most spectacular one, because it crosses the barrier between two separate kingdoms of life !

After 1.4 billion years of separate evolution, they develop the same thing, in exactly the same way ! This is evolution at its finest, and yet another example that (as childish as this may seem) mother nature rocks.

Picture via Discover Magazine