Bats, Dolphins and the Genetic Evolution of Echolocation

 Dolphins, bats and echolocation genetic evolution

What is the similarity between a bat and a dolphin? Most people’s immediate answer would be “not a lot.” However, a group of researchers have recently sought to investigate the genetic profiles of these two unrelated species, based upon a single similarity in their behavior. The group want to know whether their ability to use echolocation signifies they have rudimentary genetic ties, molded by their environment.

Convergent Evolution

A species’ evolution is typically thought to be based upon divergence of genes. Different genes code for different proteins and regulate various cellular processes and mechanisms; hence, evolution can result in a potential changeup on a cellular level, which can then have an impact upon what is known as an organism’s phenotype, the physical and behavioral traits an animal demonstrates based upon genetic expression.

However, according to recent studies, certain traits may appear around about the same period of time, across several species. This occurs due to selection pressures, where an environmental condition, to which several species are exposed, causes a number of species to develop the same traits and behaviors that confer them some new advantage and increases their chances of survival in the wild. This is referred to as adaptive phenotypic convergence.

An example of such convergent evolution has already been witnessed in a huge number of species, including birds, bats and a number of insects. These different species all developed wings, independently of one another and “converged” around this highly beneficial trait. Anatomically, however, the wings of these species differ considerably, with huge structural differences evident upon inspection.

ichthyosaurs, dolphins and sharks

Meanwhile, dolphins, sharks and, the now extinct, ichthyosaurs all demonstrated the same convergent evolution, with mirroring body shapes that facilitated streamlined movement through water. But, could bats and dolphins really have experienced the same genetic evolution to develop echolocation?

The Study

The study’s authors sought to investigate the genetic sequences of two species of animal that were thought to have evolved independently – bats and bottlenose dolphins. Both bats and bottlenose dolphins use a similar echolocation technique to navigate their surroundings. This led the research team to determine whether their might be genetic similarities between the two species, explaining their phenotypic trait for echolocation.

Researchers looked at the genomic sequences of 22 mammals, consisting of different species of bats (including the greater false vampire bat, Parnell’s mustached bat, the large flying fox and the straw-colored fruit bat) and the bottlenose dolphin. The genome-wide survey used specialized computer programs to analyze the probability that particular convergent adaptations were purely introduced by coincidence.

Echolocation

Echolocation relies upon the animal emitting bursts of ultrasonic waves and detecting the deflected waves, which bounce off environmental objects. Determining the distance between the animal and a particular object is achieved by measuring the delay between initial transmission of the sound wave and then receiving it. The greater the distance between the animal and the object, the longer the delay.

Ultimately, this is a very simplistic description of the process, which is far more complex when put into practice. The animal in question is also capable of computing the intensity of the waves reaching each ear, and the time delay for a given sound wave to reach each ear, which helps to generate a more comprehensive sense of any object’s location and also provides information regarding its size.

Bats and dolphins have echolocation capabilities

Echolocation helps animals find objects, hunt prey and move seamlessly through their environment. In addition, many animals, including dolphins, are thought to use echolocation as a form of communication between different members of their community.

Findings

Bottlenose dolphins and bats seemed to show considerable genetic convergence, including within genes that had been implicated in hearing and vision.

Dr. Joe Parker of the Queen Mary School of Biological and Chemical Sciences, who was the paper’s lead author, explained the startling results obtained from their research. He maintains the group were only expecting to identify around a dozen identical changes to some of the genes, but, in actual fact, they stumbled across 200 genes with these identical convergent alterations.

These 200 genes all demonstrated a “convergence signature” profile, showing that natural selection plays a major part in the convergent evolution of the species. These patterns only existed between echolocating bats and the bottlenose dolphin; non-echolocating bats did not reveal the same genetic changes.

Convergent Evolution in bats and dolphins

Dr. Stephen Rossiter, the research group’s leader, claims their work to be “… the tip of the iceberg,” as the genetic sequencing and analysis of additional species could yield even further patterns of convergent evolution between different mammalian species. In addition, further research could also be conducted into other traits, including neurological, digestive and social behavior, to name but a few. So, now we know that bats and dolphins share some rather remarkable evolutionary similarities, and not just simply involving echolocation.

By: James Fenner

Nature Journal Link

Queen Mary Press Release

CBS Article Link

14 Responses to "Bats, Dolphins and the Genetic Evolution of Echolocation"

  1. creme1237   March 16, 2014 at 1:18 pm

    Are these pics copyrighted??

    Reply
  2. Saskia   November 20, 2013 at 11:56 pm

    @N.E., yes but then why aren’t there any other species that echolocate? If dolphins and bats shared an echolocating common ancestor, that ancestor would also be shared by horses, rhinos, giraffes, dogs and cats, sea lions, hyenas…..
    I suppose you could say that everything lost echolocation except for these species, but it’s certainly not a simple explanation for it.

    Reply
  3. Gary Branigan   September 5, 2013 at 9:44 pm

    Are there not also echo locating cave swallows? We’re they part of the study?

    Reply
  4. jackpinesavage   September 5, 2013 at 9:23 am

    The “simple cell” presented in my high school biology text is a myth and the ongoing discovery of the marvelous complexity of organisms and the natural world would lead reasonable people to a belief in intelligent design. Darwins’ theory, as an explanation of the origin of life, is dead.

    Reply
    • Kay987   September 5, 2013 at 9:40 am

      “would lead reasonable people to a belief in intelligent design” sounds like a call for religious belief which I, for one, as a “reasonable” person find is like shrugging our shoulders. There are things that we do not understand and they are not necessarily things of a godlike designer. We simply need to do the research these writers are referring to. Research what you do not comprehend and raise your sights in the process.

      Reply
      • Louis Savain   September 5, 2013 at 9:49 am

        Believing that natural selection created complex identical genes in distant species sounds like a call for the widespread belief in mindless superstition which I, for one, dismiss as religious propaganda.

        Reply
        • Kay987   September 5, 2013 at 9:58 am

          Louis, I fully agree with you on that point, but we still must do careful examination of facts before we conclude origin.

          Reply
          • Louis Savain   September 5, 2013 at 11:06 am

            The evidence is clear and there is no need to spend decades to arrive at a conclusion. Not that evolutionary biologists have already concluded that complex identical convergent genetic codes in distant species are the result of natural selection regardless of how stupid the conclusion is. This is obviously a sign of religious fanaticism in the face of solid falsification.

      • jackpinesavage   September 5, 2013 at 11:50 pm

        >>>Kay987 “We simply need to do the research these writers are referring to. Research what you do not comprehend and raise your sights in the process.” My own goal in contemplating my own and the universes’ existence is simple truth. I recognize that my own lifespan is so short that I don’t have the time to waste chasing false leads. It is my opinion that Gerald Schroeder (author; The Science of God), has distilled this discussion in his book. Chapter 7 specifically discusses the commonality of sonar shared by “bats and birds, whales and dolphins.” In this forum, I can only strongly recommend this resource. ISBN# 0-7679-0303-X, about $15.00. I hope you don’t see this as a cop-out, but rather as an invitation to discover and enjoy.

        Reply
  5. Louis Savain   September 5, 2013 at 9:05 am

    “These 200 genes all demonstrated a “convergence signature” profile, showing that natural selection plays a major part in the convergent evolution of the species.”

    This is a lie, of course, since it shows no such thing. There is absolutely no way natural selection can create identical genes in species that are in different branches of the genetic tree. This is absurd. Why do these evolutionists insist on insulting the people’s intelligence? We are not as stupid as you think we are.

    These genetic similarities between echolocating bats and whales are 100% proof that these animals were designed by highly advanced genetic designers who did what sensible intelligent designers do all the time: they copied the tried and tested genes created for one species into another. Why reinvent the wheel (which is what would be expected in convergent evolution via natural selection) when you have good code lying around?

    Reply
    • Harek Asgardsheim   October 5, 2014 at 4:18 pm

      This hypothesis you present only displaces the question rather than answering it at all, unless you from all the designerists can tell us who designed your supposed designers.

      You might as well explain how Jack Frost carves every snowflake or the flight mechanism behind Santa Claus’s reindeer.

      Reply
  6. Kay987   September 5, 2013 at 8:38 am

    This raises the question of human ability to hear and locate things, e.g. traffic, potentially dangerous animals/humans. If we do not possess some admittedly minor degree of echolocation, how is it we hear so much if what is in our environment?

    Reply
  7. Enginole   September 5, 2013 at 8:34 am

    During the evolutionary trail there had to be many animals that started, but did not make the complete trip…animals that simply died out due to the evolutionary process. Where are these fossil records?

    Reply
  8. N.E.   September 5, 2013 at 7:44 am

    On the other hand, echolocation might have developed followed by speciation. In this case, non echolocating bats simply lost the trait vs

    Reply

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