- •Male crickets on two Hawaiian islands recently lost song-producing wing structures
- •Silence protects mutant males from attack by acoustically orienting parasitoids
- •Mutant wing phenotypes are distinct on each island and are linked to different loci
- •This pattern is best explained by extremely rapid convergent evolution
Science, Art, Litt, Science based Art & Science Communication
Convergent evolution before your eyes!
Many times people who are evolution deniers (creationists) argue that there is no proof of evolution. It takes thousands of years for evolution to take place and therefore it cannot be observed and proved. We have only fossils to contend with. And deniers don't accept DNA markers as proof because they cannot see it with their unaided eyes!
All of these (the list is by no means complete) convincingly supports the theory of evolution and the age of the earth:
Fossils (transitional forms, extinct species, fossilised footprints, marine fossils on mountain tops)
Faunal succession
Lithologic stratigraphy
Superposition of geological strata
Genetics
Radiometric and radiocarbon dating
Dendrochronology
Plate tectonics and continental drift
Comparative anatomy
Convergent evolution
Atavisms
Homology
Artificial selection
However, we have proof of micro-evolution i.e., developing drug resistance in micro-organisms is proof of micro-evolution.
But surprisingly, scientists recently observed convergent evolution before their own eyes!
Evolution is normally described as the consequence of freak mutations winding up helping a species adapt and change.
''Rapid Convergent Evolution in Wild Crickets''
Highlights
Summary
The earliest stages of convergent evolution are difficult to observe in the wild, limiting our understanding of the incipient genomic architecture underlying convergent phenotypes. To address this, we capitalized on a novel trait, flatwing, that arose and proliferated at the start of the 21st century in a population of field crickets (Teleogryllus oceanicus) on the Hawaiian island of Kauai. Flatwing erases sound-producing structures on male forewings. Mutant males cannot sing to attract females, but they are protected from fatal attack by an acoustically orienting parasitoid fly (Ormia ochracea). Two years later, the silent morph appeared on the neighboring island of Oahu. We tested two hypotheses for the evolutionary origin of flatwings in Hawaii: that the silent morph originated on Kauai and subsequently introgressed into Oahu and that flatwing originated independently on each island. Morphometric analysis of male wings revealed that Kauai flatwings almost completely lack typical derived structures, whereas Oahu flatwings retain noticeably more wild-type wing venation. Using standard genetic crosses, we confirmed that the mutation segregates as a single-locus, sex-linked Mendelian trait on both islands. However, genome-wide scans using RAD-seq recovered almost completely distinct markers linked with flatwing on each island. The patterns of allelic association with flatwing on either island reveal different genomic architectures consistent with the timing of two mutational events on the X chromosome. Divergent wing morphologies linked to different loci thus cause identical behavioral outcomes—silence—illustrating the power of selection to rapidly shape convergent adaptations from distinct genomic starting points.
http://www.cell.com/current-biology/abstract/S0960-9822%2814%2900524-7
Populations of a male cricket on different Hawaiian islands have lost their ability to chirp as a result of separate, but simultaneous, evolutionary adaptations to their wings. The changes, which allow the insects to avoid attracting a parasitic fly, occurred independently over just 20 generations and are visible to the human eye, a study reveals.
The findings could help to shed light on the earliest stages of convergent evolution — when separate groups or populations independently evolve similar adaptations in response to natural selection.
Male field crickets (Teleogryllus oceanicus) are known for their chirping sound, which is produced by scraping their wings across one another. The wings’ veins form special structures that make the vibrations that we hear as the crickets’ song. “The mechanism is like rubbing your fingernail on the file of a comb,” says study leader and evolutionary biologist Nathan Bailey of the University of St Andrews, UK.
The nightly serenades lure in females and facilitate reproduction — but unfortunately for the males in Hawaii, the chirping also attracts a deadly parasitic fly, Ormia ochracea. The fly larvae burrow into the cricket and grow inside, killing the host when they emerge a week or so later.
Both species are likely to have arrived in Hawaii at the end of the last century — the cricket from Oceania, and the fly from North America. To protect themselves from their new enemy, large numbers of male crickets on the Hawaiian island of Kauai quickly stopped chirping.
The change seems to have been caused by a mutation that altered the shape of their wings, making them incapable of producing the chirping noise. The feat was achieved over less than 20 generations, a mere evolutionary blink of an eye, and, with the crickets living just a few weeks, a very rapid process.
This evidence suggests that the mutations happened independently on both islands, making the Hawaiian silent crickets “an excellent example of convergent evolution”, says evolutionary biologist Richard Harrison of Cornell University in Ithaca, New York.
Although evidence for convergent evolution can be seen throughout the natural world, it is difficult to catch it as it happens. The study shows that superficially similar convergent solutions to attacks by parasites attracted by sound “can evolve in radically different ways”, says Tom Tregenza, an evolutionary ecologist at University of Exeter, UK. “The genome can create similar results using very different sets of genes.”
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The creationists are already saying this is mere adaptation! But evolution is the change in a population over time. And these changes are beneficial for the crickets! It is a process in which the genetic structure and physical anatomy change in relation to the changes happening in the environment. This fits the 'evolution' not adaptation.
Individuals can adapt, but it takes a whole population to evolve.
Will they evolve into a new species? Wait and watch! The gene pools are separating. We can say this is earlier stages of convergent evolution. I know more observations are needed to completely mark them as new species. Now the males will have to find a new way to attract the females! I am sure they would! But this is the beginning.
A word of caution though: I think it is too early to say whether the evolution is going to be vertical or horizontal here- whether a new species is going to evolve or not. If the males adopt a different mechanism to attract the females, the females have to change or mutate too to be receptive. Then both males and females become new products of evolution. The whole scenery changes then. If some males have to chirp in order to reproduce, they will have to remain as they are and fall prey to their enemies. Natural selection will decide which type of evolution this is going to be - macro or micro.
The peppered moth case is different in the sense that the moths didn't face so much pressure as the crickets do to completely change their gene structures. The former case is just adaptation.
The moths didn't face the problem of reproduction when they had the change in colour. A simple adaptation did the trick there. Now the crickets have to think about another reproductive strategy when they stop chirping. The females have to change too to become receptive to that change. The genetic changes will become more complicated here. That is why I think this case comes under macro - level of evolution.
I agree, the changes need not be as drastic in case of crickets as we expect them to be and put them in the macro category. They need not be as small as the micro ones too. The future will tell what will happen. Let us wait and watch before coming to a conclusion.
But how wonderful it is to be able to observe this process! To fill the gaps. And have some proof!
Don't know how many more are waiting to be discovered! Creationists, watch this space!
How warp-speed evolution is transforming ecology
https://www.nature.com/articles/d41586-018-01400-y
Read another such rapid story of evolution here: http://kkartlab.in/group/some-science/forum/topics/ah-another-evolu...
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Replies to This Discussion
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http://www.talkorigins.org/faqs/comdesc/section1.html#independent_c...
29+ Evidences for Macroevolution ; Theobald. 2010. Nature.]
Evolution: Searching for the genes that separate species
Hybrid mice shed new light on the interactions between regions of the genome that help drive the evolution of new species by reducing the fertility of hybrid males.
http://elifesciences.org/content/3/e05377
When members of the same species are separated into two populations that have no contact with each other, genetic differences accumulate over time. Later, if they come back into contact, the two populations may no longer be able to breed with each other or, if they can breed together, their offspring may be infertile. When this happens, the two populations are said to be reproductively isolated and they can be classed as separate species.
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http://evolution.berkeley.edu/evolibrary/home.php
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How reliable is macro-evolution theory?
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Comments on other sites to this discussion:
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This is funny. I am a Biologist. But when you ask Biologists ( ask and see) what is the difference between Micro and macro -evolution, you get different replies. Some say only when an amphibian becomes a reptile, it is macro evolution., i.e., vertical ascent defines it. All others are micro ones (according to them if they are horizontal, i.e., if one species originates from another one within populations, it comes under micro).
Another one says when another species differentiates from the original one, it is macro.
And some say when major changes occur in the genetic makeup, it is macro and small minor changes are micro.
Okay if people say the 'reproduction criteria ' within populations should define a species - a species is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring - what about asexual organisms ( I am sure you have heard about species problem) How do you differentiate them into various species?
I think recent developments in science should be taken into account while defining a species now forgetting the old ones . Similarity of DNA is the main one.Then, a species is defined as a separately evolving lineage that forms a single gene pool. When gene pools start separating, then they become different species in such cases. That is the criteria I took, when I said this is macro-evolution of crickets!
Now, human intervention too - apart from natural selection - can cause species differentiation.
We can go on and on like this. People ask me funny questions. When there are rules in science to define something, why is it there is so much controversy? Well even when the formation of rules make you go haywire, how can you arrive at a single definition?
Blues or paradoxes of growing phases of science!
But an evolution, is an evolution, is an evolution, macro or micro !--
A giant Petri dish chock-full of superbugs shows evolution as it happens: https://www.statnews.com/2016/12/08/superbugs-antibiotic-resistance...
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Evolution the human saga
Scientific American Volume 311, Issue 2Evolution Rewritten » Awash in fresh insights, scientists have had to revise virtually every chapter of the human story
By Kate Wong--
Strategy for Dealing With Creationist Attacks on Science
http://blogs.scientificamerican.com/rosetta-stones/2015/01/28/an-of...
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here is an argument for evolution so compelling that it massively shifts the burden of proof without relying on a single fossil.
- Every organism has DNA
- Every organism has its DNA shuffled when it has offspring
- DNA affects how well that organism is going to survive
- The better an organism survives, the more its DNA will survive into the subsequent generations
- So DNA that leads to effective survival will spread.
- As the world changes and as new genetic "ideas" come into being, the world's organisms must gradually diversify.
That's evolution. Once you have a mechanism for descent with variation and selection, it's inconceivable that evolution wouldn't happen. The rest is details. Many, many details, quite a few of which are not yet known. But the overall structure is so compelling that any argument designed to prove that it didn't happen has an insurmountable obstacle to overcome, and creationists always look foolish when they try.
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For natural selection:
"Three principles will account for all
(1) Grandchildren. like. grandfathers
(2) Tendency to small change. . especially with physical change
(3) Great fertility in proportion to support of parents"
Charles Darwin, E Notebook, October 1838—July 1839, page 58
Or, in three words: heredity, variation, superfecundity. If you accept those three facts, you are intellectually committed to natural selection occurring.--
Self replication+heredity+variation+environmental pressures+limited resources+time = evolution
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Anybody can verify for themselves with their own eyes that mutations exist.
Anybody can verify for themselves with their own eyes that selection exists.
Mutation + Selection = Evolution.--
https://en.wikipedia.org/wiki/E._coli_long-term_evolution_experiment
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Same dance, different species: How natural selection drives common behavior of lizards
https://phys.org/news/2021-07-species-natural-common-behavior-lizar...
Terry J. Ord et al, Deep‐time convergent evolution in animal communication presented by shared adaptations for coping with noise in lizards and other animals, Ecology Letters (2021). DOI: 10.1111/ele.13773 -
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What is the best evidence for evolution?
http://www.quora.com/What-is-the-best-evidence-for-evolution
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Mosaic evolution - where subsets of traits evolve independently of others - painted lorikeets a rainbow of colour ...
https://phys.org/news/2020-02-mosaic-evolution-lorikeets-rainbow.ht...
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Line of defense: Scientists report surprising evolutionary shift in snakes
https://phys.org/news/2020-02-line-defense-scientists-evolutionary-...
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15 Answers to Creationist Nonsense
Opponents of evolution want to make a place for creationism by tearing down real science, but their arguments don't hold uphttp://www.scientificamerican.com/article/15-answers-to-creationist...
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fossils of intermediate species
http://www.quora.com/Trolling-Questions/If-evolution-is-true-then-w... -
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Metabolism: Evolution retraces its steps to advance
Bacteria in a long-term evolution experiment evolved a new metabolic trait via two separate mutations with opposite effects.http://elifesciences.org/content/4/e12386?utm_source=content_alert&...
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Predators key to helping prey evolve with climate change
The key to helping animals evolve quickly in response to climate change could actually be their predators, according to a new UBC study.
The study is one of the first to show that species interactions, meaning the way species interact with each other in an ecosystem, like in a predator-prey relationship, is important to understanding how animals will respond to climate change. The findings, published today in Biology Letters, have implications for ecosystems around the world where many top predators like sharks or polar bears are disappearing because of increasing pressure from climate change and human populations.
"Not only can predators keep prey populations in check but in some cases they can help speed up the evolutionary response to climate change," said Michelle Tseng, a research associate in UBC's Department of Zoology and lead author of the study. "We now understand that species interactions and evolution can play a significant role in preventing animals from going extinct in a rapidly changing climate."
For the experiment, Tseng and her colleague Mary O'Connor, an assistant professor in the Department of Zoology, studied a small crustacean known as the water flea or by its Latin name Daphnia. These tiny organisms are key members of freshwater ecosystems around the world, and healthy lakes are typically filled with Daphnia or other similar species.
In the experiments Daphnia did not show any evolutionary response to increased temperature when there were no predators in the environment. When they lived alongside their predators, in this case a predatory fly larva, Daphnia populations evolved very quickly to a three-degree increase in water temperature.
Until recently scientists had little idea if species could evolve fast enough to save themselves from extinction in the face of climate change. In laboratory settings, a few studies had shown that some species could evolve rapidly, but these lab conditions were not very realistic.
Tseng and O'Connor set out to better understand how organisms may react to climate change in more realistic situations like those where they have to cope with finding food, finding a mate, or escaping from predators.
The UBC zoologists were surprised by their results. They thought the predators would eat enough Daphnia that their population sizes would be too small for evolution to occur; instead the opposite happened.
"In nature, no population lives in isolation," said Tseng. "The community plays a big role in whether and how an organism responds to climate change. These results highlight the importance of conserving the entire ecosystem instead of protecting just one species."
BACKGROUND
In the experiment, when the Daphnia lived alongside their predators, the populations evolved very quickly to a three-degree increase in water temperature.
The researchers believe evolution to warmer temperatures sped up with predators because the predators preferred to eat those Daphnia that happened also to be bad at coping with warmer temperatures.
The combination of predators and warmer temperatures resulted in an evolutionary shift in the population from a larger-bodied, more slowly reproducing population, to a population that was 10 per cent smaller in body size, and twice as fast at reproducing. This trend of both temperature and predators causing smaller body sizes is not uncommon in nature, which leads the researchers to think this benefit of predators for evolutionary rates might not be specific to just Daphnia.
http://www.eurekalert.org/pub_releases/2015-12/uobc-pkt121515.php -
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Paul Stregevsky:
Kenneth Krause
Paul predicts the creationist argument well. Macroevolution implies speciation, the definition of which can, in some cases, be rather superficial and arbitrary (tigers can successfully mate with lions, e.g., as I understand it), but usually requires reproductive incompatibility. So the convergent evolution of fly wings would be unimpressive to some religionists. That said, I personally think it's very impressive. Darwin's dangerous idea in action continues to fascinate.
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There's only so much you can change and still be functional," Kim Worley, a genome biologist at Baylor College of Medicine recently told New Scientist.
( http://www.newscientist.com/article/dn26857-tape-of-life-may-not-...
She explained that because there are only so many ways for a terrestrial animal to adapt to aquatic environment, it may have really limited what kind of mutations could help. All others, predictably, would prove lethal.
Evolution may have fewer options for adapting to new challenges than you'd think.
But for 15 genes, natural selection led to exactly the same genetic changes occurring in all three lineages. This suggests that for some of the challenges of life in the sea, evolution repeatedly arrived at the same solution – that is, replaying the tape does indeed give much the same result again and again. This is a high-resolution replay of the tape, looking at what would happen to individual lineages, rather than what overall diversity would eventually result, which is what Gould looked at.
This may imply that the vast majority of mutations are lethal, so that evolution stumbles on the same few viable ones over and over again. "We think it's because there's only so much you can change and still be functional.
http://www.newscientist.com/article/dn26857-tape-of-life-may-not-al...
If you replayed the tape, you'd probably see the same changes again amongst the marine mammals, but if you took a walrus and a camel, you'd still see the same changes, because of these constraints.
http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.3198.html
http://www.natureworldnews.com/articles/12304/20150127/radical-evol...
Radical Evolution Isn't as Random as You'd Think
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New Lizard Shows Evolution’s Predictability
A new anole on the island of Hispaniola confirms that ecological communities can follow predictable patterns.
https://www.quantamagazine.org/20160629-new-lizard-shows-evolution-...
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Research on soldier ants reveals that evolution can go in reverse
https://phys.org/news/2020-03-soldier-ants-reveals-evolution-revers...