The asymmetry of existence: do we owe our existence to cold dark matter and the weak force?

A common theme throughout biology is homochirality, including its origin and especially implications. Homochirality has also intrigued scientists because of the hypothesis that life, as it currently exists, could not have occurred without it. In this review, we discuss several hypotheses regarding homochirality and their linkage to processes that range from subatomic in scale to processes that help define the structure of the universe. More importantly, this exploration begins with the knowledge that humans inhabit the universe in which there is an excess of normal matter over antimatter. It is a universe characterized by homochirality but is nonetheless contained in what is most easily described as a 3+1 dimensional spacetime wherein most laws of physics are invariant under spacetime transformations. This restriction on spacetime poses significant constraints on the processes that can be invoked to explain homochirality. However, in dealing with such restraints, including the total mass contained in the universe, the concepts of cold dark matter and dark energy can be incorporated into cosmological models with resultant behaviors and predictions very much in accord with the findings of the cosmic background surveys. Indeed, the introduction of cold dark matter and dark energy to solve problems relating to the mass found in the universe may provide a means for generating the needed asymmetry to allow homochirality to arise.     

How silent is the brain: is there a “dark matter” problem in neuroscience?

Evidence from a variety of recording methods suggests that many areas of the brain are far more sparsely active than commonly thought. Here, we review experimental findings pointing to the existence of neurons which fire action potentials rarely or only to very specific stimuli. Because such neurons would be difficult to detect with the most common method of monitoring neural activity in vivo—extracellular electrode recording—they could be referred to as “dark neurons,” in analogy to the astrophysical observation that much of the matter in the universe is undetectable, or dark. In addition to discussing the evidence for largely silent neurons, we review technical advances that will ultimately answer the question: how silent is the brain?     

"Craziness" and "visions": experiences after a stroke.

For a stroke victim there may be at least three types of strange occurrences: incorrect saying, seeing, and thinking. To the patient only the third seems to be "crazy". After a stroke (left hemisphere), which mainly produced serious aphasia, I (the patient) felt crazy two or three times when someone said something I expected him to say. On the other hand, my initial aphasic "gibberish speech" and an occasional false vision did not seem crazy. In my case the vision is always a car or a child, seen on my extreme right, where I am otherwise blind from the stroke. I am always driving when it happens; in recent years this phenomenon occurs when I am tired or tense, or the light is poor. These rapid visions do not seem insane but merely physical problems in my eyes, much like ordinary people''s dreams.     

What is life?

Background

Many traditional biological concepts continue to be debated by biologists, scientists and philosophers of science. The specific objective of this brief reflection is to offer an alternative vision to the definition of life taking as a starting point the traits common to all living beings.

Results and Conclusions

Thus, I define life as a process that takes place in highly organized organic structures and is characterized by being preprogrammed, interactive, adaptative and evolutionary. If life is the process, living beings are the system in which this process takes place. I also wonder whether viruses can be considered living things or not. Taking as a starting point my definition of life and, of course, on what others have thought about it, I am in favor of considering viruses as living beings. I base this conclusion on the fact that viruses satisfy all the vital characteristics common to all living things and on the role they have played in the evolution of species. Finally, I argue that if there were life elsewhere in the universe, it would be very similar to what we know on this planet because the laws of physics and the composition of matter are universal and because of the principle of the inexorability of life.

     

Joan Heath interviews Suzanne Cory and Joan Steitz: a female perspective of science in the swinging ‘60s

Prompted by the occasion of International Women''s Day, Joan Heath and DMM reunited Professors Suzanne Cory and Joan Steitz via Zoom to discuss their extraordinary careers and joint experiences in science. They also delve into past and present challenges for women in science, and discuss the role of scientists in a post-pandemic world.

Suzanne Cory, Joan Steitz and Joan Heath (from left to right) As one of Australia''s most eminent molecular biologists, with a school in Melbourne bearing her name, Professor Suzanne Cory has been both Director of The Walter and Eliza Hall Institute of Medical Research in Australia (WEHI) and President of the Australian Academy of Science. She earned her PhD at the Medical Research Council (MRC) Laboratory of Molecular Biology (LMB) in Cambridge, UK, with postdoctoral training at the University of Geneva. She continues her research at WEHI as an honorary distinguished research fellow, investigating the genetics of the immune system in the development of blood cancers and the effects of chemotherapeutic drugs on cancer cells.Joan Steitz – currently Sterling Professor of Molecular Biophysics and Biochemistry at Yale University, and for 35 years the recipient of a Howard Hughes fellowship – is best known for her seminal work in RNA biology. She was the first female graduate student to join the laboratory of James Watson at Harvard University and proceeded with her postdoctoral training at the MRC LMB in Cambridge. Her pioneering research delved into the fundamental mechanisms of ribosome and messenger RNA interactions, as well as RNA splicing, heralding the phenomenon of alternative RNA splicing. A recipient of many awards and honours, she is also involved in international projects aimed at supporting women in science.Host Joan Heath heads a laboratory at WEHI in Australia. She received her undergraduate degree from the University of Cambridge, followed by her PhD at the Strangeways Research Laboratory also in Cambridge, then just across the road from the MRC LMB. After postdoctoral positions in bone biology and osteoporosis research, Joan joined the Ludwig Institute for Cancer Research where she became a laboratory head, and changed her focus to cancer research using zebrafish to identify genes that are indispensable for the rapid growth and proliferation of cells during development. She joined the WEHI in 2012. There she showed that the same developmental genes are also required by highly proliferative, difficult-to-treat cancers, including lung, liver and stomach cancer, paving the way for translational research targeting these genes in novel cancer therapies. Joan H: How long have you two known each other? Suzanne: I was calculating that this morning and I was astonished because it seems like only yesterday, but it has been 55 years since we met in Cambridge. It has been a voyage in science and a voyage in the world because we have always made a point to meet up in beautiful places and go hiking. That is how we''ve been able to renew our friendship over all these years. Joan H: Where were you when you first met? Joan S: We both were working at the MRC LMB in Cambridge, England. Suzanne was doing her PhD and I arrived slightly later for a postdoc.Suzanne: We had a pre-meeting in the sense that Joan, Jerry Adams (my future husband) and Tom Steitz (Joan''s husband), were all graduate students together in Harvard. So, when Joan and Tom came to Cambridge, it was natural that we would all start doing things together. And Joan and I ended up sharing a lab bench.Joan S: The reason that I did a postdoc in the mecca of X-ray crystallography was that I had married a crystallographer – and there was no other place that he could possibly go. They very much wanted to have my husband at the Cambridge MRC lab, but there wasn''t a clear plan for me. Francis Crick suggested that I do a literature project in the library, but I knew that theory was not my forte in comparison to experiments. I started talking to the many people working in the lab and found a project that no one wanted, because it was so challenging. But it was a very interesting problem, so I decided to take it on – and it turned out to be a great project.Joan H: That''s amazing. You were obviously determined to overturn other people''s expectations of you.Suzanne, even now, it''s extremely unusual for a young person to leave their home country to do their PhD. It''s still a brave thing to do but all those years ago it was really courageous. You told me that you ended up there because you wrote a simple letter, which was a complete shot in the dark.Suzanne: It certainly was. During my master''s degree at the University of Melbourne, I became more and more interested in doing science and decided I would do a PhD. But I had a counteracting desire to travel and see Europe. So I decided that I would do my PhD overseas to give myself the opportunity of travelling. I had fallen in love with DNA during my undergraduate studies. So, I wrote a letter to Francis Crick in Cambridge, and asked if he would take me on as a PhD student. Much to my amazement, I eventually got a letter back saying yes. I think that my professor of biochemistry might have also visited Cambridge while he was travelling and spoken up for me. However, I was still extraordinarily fortunate that Francis had agreed because there weren''t many PhD students in the LMB at that time. It made such a difference to my entire life. I look back on that letter and think, “How did you have the audacity to write that letter and aim to go to that laboratory?”. I think it was partly naivety.Joan H: That''s a lesson for everyone, to go for your dreams, and don''t assume people won''t take notice of you. It is more difficult now, when scientists receive hundreds of e-mail applications from prospective PhD students in their inbox. You would have written a letter with a stamp on it that probably took three weeks to arrive, but it just shows you that you should be audacious. Did you have a different experience to Joan when you arrived? Was there a proper project already lined up for you?Suzanne: I was interviewed by Francis Crick and Sydney Brenner, who were the joint directors of the department. They decided that I would work on the structure of the methionyl-tRNA that puts methionine into internal positions in polypeptides. After they described the project – which involved doing counter-current distribution fractionation of bulk tRNAs, in which I had no experience whatsoever – Sydney in his very characteristic monotone said, “Do you think you''re up to it?”. I sort of gulped to myself and said, “Yes, I think I could do that”. I then went to Brian Clark''s laboratory, who was going to be my PhD supervisor, and started the project. Like always in life, if you learn from people and just go from one day to the next, you actually get there in the end.Joan H: So, persistence was key. Were there many other women at the LMB at the time?Suzanne: I don''t remember any female scientists who had official senior positions. There were certainly some strong female scientists there, but I don''t think they were given the recognition or the status that they actually deserved.Joan S: Later, some were given more recognition, crystallographers in particular, but not so much the molecular biologists.Suzanne: I think, as women, we both pioneered in that department.Joan H: Given the fact that you both agreed to take on projects you had very little previous experience with and that the male supervisors thought you weren''t going to have the mettle to carry it through, once you were there, did you feel that you had to work the whole time? Or did you still manage to have lots of fun and partake in opportunities that Cambridge had to offer at the time?Joan S: We certainly partook in a lot of those things. My husband and I got interested in antique furniture, antique paintings, and used to scour the countryside for little antique shops. We saw lots of England, then a little bit of Scotland and Wales. It was wonderful. A real adventure.Suzanne: I worked really hard most of the time that I was in Cambridge, as the work was very exciting. But I would take holiday periods, camping and youth hostelling all over Europe with a girlfriend from Melbourne and later, travelling with Jerry. We also would go to London for the opera and looking for amazing clothes on Carnaby Street and Chelsea Road (this was the Beatles era, late 60s). Jerry once came back with a purple velvet suit, which was his prized possession for many years. There was lots of fun but also lots of work.Open in a separate windowJoan Steitz, Tom Steitz, Jerry Adams and Suzanne Cory (from left to right) in the Swiss Alps, 1970. Image courtesy of Mark Bretscher. This image in not reproduced under the terms of the Creative Commons Attribution 2.0 Generic license. For permission to reproduce, contact the DMM Editorial office. Joan H: Can you remember the first moment in that part of your career that gave you the most pleasure? Joan S: I worked on a project for about a year, and it turned out that I was doing the wrong fractionation method to get the material that I needed to analyse. Then I had a conversation with Sydney Brenner telling him that I was going to give this one more try with a new method, and then I was going to give up. I remember Sydney saying, “Sometimes, like with a bad marriage, you have to give experiments one last try before you give them up.” Then I tried again, and it worked. This is often the case in science, that you try something new, that''s a little bit different, and it makes all the difference. Then you''re running.Suzanne: The same thing happened to me. I was labouring away on the counter current distribution machines fractionating methionine tRNA, with the goal of sequencing it by the laborious procedure recently published by Robert Holley. However, Fred Sanger, in the department upstairs, had invented a totally new method for sequencing using ³²P-labelled RNA. I desperately wanted to try this, so I managed to persuade my supervisor that we should change techniques. That change was key to my future because the approach was successful. I still remember to this day exactly where I was in Cambridge, walking on a Sunday afternoon, when the last piece of the puzzle dropped into place in my mind, and I had the entire sequence. In that moment, I was extremely joyful, because I knew I had my PhD and that I had succeeded. So that was my eureka moment.Joan H: Obviously, these were extremely productive years, and you''ve mentioned several Nobel Prize winners in your midst. It must have been the most inspiring environment, which I''m sure had a big impact on what you did next. By this stage in your career, were you already feeling ambitious or was it still your scientific curiosity that was driving your path?

“I expected that I would go back to the United States and be a research associate in some man''s lab […]. Then it turned out that people were more impressed than I thought and started offering me junior faculty jobs.”

Joan S: I had gotten a lot of recognition for having sequenced a piece of mRNA, using the same methods that Suzanne used to sequence tRNA. However, I had no expectations, because I had never seen a woman as a science professor, or head of a lab. I expected that I would go back to the United States and be a research associate in some man''s lab, and maybe they''d let me guide a graduate student. Then it turned out that people were more impressed than I thought and started offering me junior faculty jobs.My husband had already secured a junior faculty job in Berkeley before we even went to England, so we went back there after two years. My husband went to the chair of the department in Berkeley and put down letters on his desk of job offers that both of us had received for independent, junior faculty positions from several universities. The Chairman then said to Tom, “But all of our wives are research associates in our labs, and they love it”. This tore at my pride, as there had been a couple of universities that offered us both faculty jobs, and Berkeley was only offering one. So, we didn''t stay at Berkeley, and we came to Yale, which was wonderful.Suzanne: It''s really amazing to think that they gave you up. How foolish they were.Joan H: They''ve lived to regret it a million times over. Suzanne, at that point were you ready to climb this very difficult ladder?Suzanne: Like Joan, I didn''t have any expectations. For me, it was a matter of being able to continue discovering things in science. Jerry had already arranged to start a postdoc in Geneva. So, I applied for a postdoctoral fellowship, and obtained one. We went off together to Geneva to start our married life, and that was the beginning of us doing science together, which we''ve done ever since. I think without Jerry guiding me at that stage in my life, I would have probably drifted out of science. I don''t think I had the scientific confidence to ever think that I would be running a lab. For me, it was just continuing a voyage of discovery; and being lucky to end up in a wonderful scientific partnership and, through that partnership, my confidence grew over the years. Joan H: How many years after your postdoctoral training was it before you looked around your environment and had the confidence to think that you could be a lab or department head or could run an Institute? Joan S: I would say that confidence just grew. Tom and I were part of a departmental overhaul that involved hiring about six new people at Yale. We all stuck together, supported each other and were very collegial even though we worked in different areas. I think the collegial nature of the department in Yale helped me gain confidence. It was very scary at first because I didn''t know if I could write grants or direct people.Suzanne: Cambridge had an incredible influence, certainly over me, and I''m sure over Joan, Tom and Jerry, too. We looked around and saw all these amazing Nobel laureates, but also all these very ambitious, talented postdocs from around the world. I don''t think anyone thought about being the head of a department at that stage. We were simply striving to make discoveries and we gave each other mutual confidence, and stiff competition, too.The other thing that Cambridge gave us, was a new technology. For Joan and me, it was RNA sequencing. Being able to do that technology opened doors all around the world. I now always advise young people to go to the best place in the world to train in your chosen subject and acquire a new technology, because that will open the door to many opportunities in the future.Jerry and I made some excellent discoveries in Geneva, which were published in front-rank journals. Then it was time to move to full independence. I really wanted to go back to Australia but, as Jerry is an American, it was not at all obvious that he should take the big leap of moving to the bottom of the world and starting a lab there. I owe him a tremendous debt because he decided that he would take that risk.Earlier, whilst on our honeymoon, we had visited various labs in Australia. Although WEHI was an institute for immunology, a field we knew little about at that stage, it had the same atmosphere as the LMB in the sense that everyone was striving at the frontiers of science and competing with the rest of the world. We decided this was the only place in Australia that we would work at and that we would attempt to persuade the new director Gus Nossal that he needed molecular biologists. We had an interview with him in Switzerland and he offered us jobs as postdocs. Again, we were probably very naive and audacious but we told him we didn''t want to be postdocs – we wanted to run our own lab. And he agreed and we launched our fledgling lab together in 1971. What drove us was always discovery, rather than career ambitions.Joan H: You''ve both described these amazing sets of circumstances that were challenging but, nevertheless, very satisfying. However, a lot of things have since changed. What do you think are the main remaining barriers to women in science?Joan S: There is an important phenomenon called social identity threat, or stereotype threat, that I think still impedes women in proceeding in their careers. The phenomenon is described by cognitive psychologists as a reaction that all people experience if they feel that they are part of an undervalued minority. And so, by definition, since there are fewer women in science than there are men, women are being subjected to stereotype threat. Cognitive psychologists have studied the physiological manifestations of this, including increased heart rate and perspiration but, psychologically, they''ve also documented that cognitive learning and memory are impaired when one has these feelings.I first learned about this in 2007 and I looked back and realized why, for 30 years, when I''d been on committees as the only woman amongst ten men, I wouldn''t dare say anything – because I was frightened stiff. Men undergo this response, too, if they''re put into the situation of being undervalued. If you understand why you''re reacting the way you''re reacting and know that this is a normal human response, I think it helps you to overcome your own feelings of insecurity and allows you to go ahead. I always tell young women who I''m rooting for in science about this, because I want them to know that they will very likely end up feeling this way, and it''s a normal human response.

“One thing I sometimes get frustrated about is that we often need men to change things […] but what we really need are women in those high-level positions, so that they can be the champions of change.”

Joan H: There are other terms describing other relevant phenomena, such as unconscious bias, imposter syndrome and champions of change. One thing I really relate to is imposter syndrome. I''ve listened to webinars on this topic and they all reach a similar conclusion that we all feel the same. On the one hand, at the end of the webinar, you do feel somewhat elated to know that it''s not just you, and that it''s normal. But, on the other hand, it doesn''t really change things. It''s a recognition of what we feel, and we all get some help from that, but you really need opportunities to change things at a higher level. One thing I sometimes get frustrated about is that we often need men to change things, leading to this concept of male champions of change. I admire those men; but what we really need are women in those high-level positions, so that they can be the champions of change. Not having 50% of university departments and medical research institutes run by women still limits our full potential.Joan S: I certainly agree with you, Joan. It''s very important to have realistic role models. Suzanne being head of the WEHI for all those years has engendered all sorts of admiration.Joan H: During that period, Suzanne not only did fantastic science but our Institute doubled in size.It''s transformative when you have women making up 50% of people around the table. It''s no help just having a token female because that poor person''s not going to be able to change everything on her own. In American scientific institutions, are there any firm quotas for female scientists and other people that are underrepresented in science?Joan S: In recent years there has been a push in that direction. Sometimes it''s successful and sometimes it''s not. It is very different now compared to when there was no consciousness that this was unfair or that things could be better if we had real representation.Suzanne: I agree with both of you in everything that''s been said. While reflecting at this moment, what it says to me is that what''s really needed is societal change, and that we need to give courage to girls from the very earliest age. It should come naturally, they shouldn''t feel inferior, and others should not look at them as inferior. They should expect to have careers as well as families, be able to manage both and have somebody alongside them who helps them manage both.I think that affirmative action for women in science is necessary because the pace of change has been so slow. However, I also think quotas can be detrimental to the cause of women, in the sense that it''s then possible for people to say you only made it because there was a quota – which is very destructive. If I look back on our careers in science, it is clear that things have changed tremendously. Today there are more opportunities for women because many universities and institutes are bending over backwards to equalise things. The downside of this is that talented men may miss out on positions because of this policy and the pendulum could swing back.Joan H: The evidence shows that when more women are involved in things, those things go better. For instance, boards that have more women on them are more productive. Obviously, what you alluded to is there are lots of fantastic male scientists as well. The real issue here is there''s not enough funding to go round to support all the great men and women. But there are clearly enough good women around to be represented at the 50% level, without disproportionately disadvantaging male scientists.Joan S: Men and women are now operating on a more even playing field, which doesn''t mean that the men are missing out. They''re just in a more-competitive situation – as they should be. Joan H: Suzanne previously covered the specific advice she would give to young female researchers. Joan, do you have any other suggestions? Joan S: I encourage them to try lots of different things in science, and when they find something that really grabs them, then go for it and be persistent. We all know that science is very up and down. But if you keep pushing when you''re in a trough, it will always go back up again and you will succeed. That''s harder for a young person, who hasn''t experienced these troughs, to understand.Joan H: Yes, and the period when women scientists start having children is the hardest part. It''s still a choice that some women make, to take some years off and come back with a less ambitious plan for their career. Obviously, things like maternity leave payments and so on are improving but there''s no question that, in most circumstances, the research will slow down during that period.Suzanne: What I say to young women at that stage of their careers is that you have to be very focused, you must spend the time that you do have in a very focused manner, so that you can be the most productive you can be. But you have to be supported at home by your partner. If you''re both scientists it''s easier because you can appreciate why the other person is rushing into the lab late at night, for example, but for most people, that''s not true. So, what is really important is equal sharing of responsibilities from both partners when young families are around. And I think employers need to give both of those partners a longer time to achieve the kind of papers that they need to progress in their careers. That''s a period when it is much harder to be productive, and we need to continue to support people during that difficult phase of their careers because we''ve invested so much in them. They have so much to offer to science and to society, so to let them slip out at that stage is a great waste.Joan H: Let''s change tack a little bit and think about some of the broader challenges in science. What do you think the COVID-19 pandemic has taught us about the importance of clear scientific communication and real engagement with the community?Joan S: Whenever I talk to people about this, I very clearly make the point that it was decades of fundamental research that led to the development of the COVID-19 vaccine. If it hadn''t been for those fundamental discoveries in how cells and mRNA work, it would never have only taken 63 days from sequencing the virus to phase one clinical trials at Moderna. I try to point out to people that all the different discoveries coming in from different angles made that possible. I personally find it absolutely remarkable that all that knowledge could be harnessed, so very quickly. I''ve been doing fundamental research my entire life and I never expected to see it materialise in the way it has. It''s a wonderful reward. Joan H: Do you think this has resulted in the community appreciating scientists more? Joan S: I don''t think we''re far enough downstream to know that. In the US, there has been a congressional vote to abandon our maintenance of vigilance and preparedness for future pandemics – which seems ridiculous. Now we have all these procedures set up, all we have to do is maintain them for the next one. Whereas, if we just let go of these procedures, we''ll have to start over again for future pandemics. I guess we''re not good enough at communicating some of these things at this point.Joan H: Millions of people died from the virus and yet, if we hadn''t had the vaccines, the scale would have been even more horrific. If we were able to convey this information effectively to the public, then, hopefully, people would recognise that – as well as spending a fixed percentage of the gross domestic product on defence, for example – we should spend at least the same amount on science. Not only for pandemics but for tackling climate change and other pressing issues. I like to think this is an auspicious time but I don''t know whether we are really taking advantage of it.Suzanne: The pandemic has brought science and scientists to the forefront, and there has been a period of great respect for scientists having developed the vaccine. It''s an absolute miracle that it was done so fast and effectively. We''re very fortunate but, as Joan said, that was not luck. It was through investment in basic science for decades. We have to keep conveying this message, to our politicians in particular, so that they will keep supporting all kinds of scientists, because we never know what''s around the corner.Joan H: Certainly, people like Anthony Fauci in the US and Catherine Bennett in Melbourne, spoke eloquently and had a real talent for communicating things clearly and in a nutshell. That''s not something we''re all good at and it''s not something that is easy to train into people either. I think we all need to try to capture the attention of the community at large, by speaking plainly. I don''t think people understand that scientists are underfunded and could do so much more if funding was more generous.

“All I can say to young people is, if you really love science and have a passion for it, keep trying – because you will succeed if you put your whole heart and soul into this career path.”

Suzanne: I think the general public has no appreciation of how tenuous the life of a scientist can be, and how we are losing so many great minds entering the field because young people just finishing their PhDs look with dismay at how hard it is to support a career in science and get enough funding. There''s a tremendous waste of talent. All I can say to young people is, if you really love science and have a passion for it, keep trying – because you will succeed if you put your whole heart and soul into this career path.Joan H: This has been an absolutely fantastic discussion and it''s such a delight to talk to women who, after all these years, are still as passionate as ever and are pursuing their scientific subjects with the same vigour as they have all along.Suzanne: It''s been wonderful to talk with you, Joan, and I hope that we see each other soon, no matter what continent. And thank you, Joan Heath for getting us together and giving us this opportunity.     

Evolutionary rescue and the coexistence of generalist and specialist competitors: an experimental test

Competition for resources is thought to play a critical role in both the origins and maintenance of biodiversity. Although numerous laboratory evolution experiments have confirmed that competition can be a key driver of adaptive diversification, few have demonstrated its role in the maintenance of the resulting diversity. We investigate the conditions that favour the origin and maintenance of alternative generalist and specialist resource-use phenotypes within the same population. Previously, we confirmed that competition for hosts among φ6 bacteriophage in a mixed novel (non-permissive) and ancestral (permissive) host microcosm triggered the evolution of a generalist phenotype capable of infecting both hosts. However, because the newly evolved generalists tended to competitively exclude the ancestral specialists, coexistence between the two phenotypes was rare. Here, we show that reducing the relative abundance of the novel host slowed the increase in frequency of the generalist phenotype, allowing sufficient time for the specialist to further adapt to the ancestral host. This adaptation resulted in ‘evolutionary rescue’ of the specialists, preventing their competitive exclusion by the generalists. Thus, our results suggest that competition promotes both the origin and maintenance of biodiversity when it is strong enough to favour a novel resource-use phenotype, but weak enough to allow adaptation of both the novel and ancestral phenotypes to their respective niches.     

The evolution of climate tolerance in conifer‐feeding aphids in relation to their host's climatic niche

Climate adaptation has major consequences in the evolution and ecology of all living organisms. Though phytophagous insects are an important component of Earth's biodiversity, there are few studies investigating the evolution of their climatic preferences. This lack of research is probably because their evolutionary ecology is thought to be primarily driven by their interactions with their host plants. Here, we use a robust phylogenetic framework and species‐level distribution data for the conifer‐feeding aphid genus Cinara to investigate the role of climatic adaptation in the diversity and distribution patterns of these host‐specialized insects. Insect climate niches were reconstructed at a macroevolutionary scale, highlighting that climate niche tolerance is evolutionarily labile, with closely related species exhibiting strong climatic disparities. This result may suggest repeated climate niche differentiation during the evolutionary diversification of Cinara. Alternatively, it may merely reflect the use of host plants that occur in disparate climatic zones, and thus, in reality the aphid species' fundamental climate niches may actually be similar but broad. Comparisons of the aphids' current climate niches with those of their hosts show that most Cinara species occupy the full range of the climatic tolerance exhibited by their set of host plants, corroborating the hypothesis that the observed disparity in Cinara species' climate niches can simply mirror that of their hosts. However, 29% of the studied species only occupy a subset of their hosts' climatic zone, suggesting that some aphid species do indeed have their own climatic limitations. Our results suggest that in host‐specialized phytophagous insects, host associations cannot always adequately describe insect niches and abiotic factors must be taken into account.     

The position of a doctor in cases of violence attack commited by a patient from the point of view of juristic theory

There is no doubt, that the medical staff has often to face aggressive patients, their threats and event their violent physical attacks today. More frequently than ever they are faced with the necessity to think over and consider very carefully the way to defend against imminent or persistent attack on them. First, I would attempt to qualify patients' aggressive behaviour - from lesser acts, when the violent attack is not imminent, through threatening with killing, inflicting aggravated bodily harm or causing exceptionally serious damage or enforcement by violence, the threat of violence or the threat of causing another serious damage, to do something, to desist from doing something or tolerate something. to the imminent or persistent attack. Then I would try to describe the best ones of possible ways of self-defence against various levels of aggressive behaviour.     

Four Ways Life Extension will Change Our Relationship with Death

Discussions of life extension ethics have focused mainly on whether an extended life would be desirable to have, and on the social consequences of widely available life extension. I want to explore a different range of issues: four ways in which the advent of life extension will change our relationship with death, not only for those who live extended lives, but also for those who cannot or choose not to. Although I believe that, on balance, the reasons in favor of developing life extension outweigh the reasons against doing so (something I won't argue for here), most of these changes probably count as reasons against doing so. First, the advent of life extension will alter the human condition for those who live extended lives, and not merely by postponing death. Second, it will make death worse for those who lack access to life extension, even if those people live just as long as they do now. Third, for those who have access to life extension but prefer to live a normal lifespan because they think that has advantages, the advent of life extension will somewhat reduce some of those advantages, even if they never use life extension. Fourth, refusing life extension turns out to be a form of suicide, and this will force those who have access to life extension but turn it down to choose between an extended life they don't want and a form of suicide they may (probably mistakenly) consider immoral.     

Give chance a chance

How did I get to become a cell biologist? Or, more generally, why do things happen the way they do? The answer provided by the philosopher Democritus and later adopted by Jacques Monod is “everything existing in the universe is the fruit of chance and necessity.” While I read Monod''s book Chance and Necessity as an undergraduate student, little did I appreciate the accuracy of this citation and how much of my scientific trajectory would be guided by chance.     

Eric Michaels: An appreciation

… I got into media studies, as an anthropologist, because I believed the media were the belly of the beast, and because I thought television was central to the creation of the extraordinary contradictions that plagued the contemporary world. [Michaels 1983]

It would seem that Malinowski's stricture that the function of the ethnographer was to see the native's culture from the native's own point of view could at last be achieved—literally, and not metaphorically.

What would such a world be like, and more importantly, what problems have we to set before our students now that will, at the least, not hinder them from coming to an understanding of an age in which man presents himself not in person but through the mediation of visual symbolic forms… It is now no longer possible for the student of culture to ignore the fact that people all over the world have learned, and will continue in great numbers to learn, how to use the visual symbolic mode. Anthropologists must begin to articulate the problems that will face us in trying to understand others when their point of view is known to us primarily through movies distributed by broadcast television and cable. [Worth 1981: 94–95]     

An encounter with extraterrestrial intelligence]

It is much easier to find extraterrestrial intelligence than to detect simple organisms living on other planets. However, it is hard to communicate with such intelligence without the mutual understanding of inter-stellar communication protocol. The radio SETI (The Search for Extra-Terrestrial Intelligence) was initiated with the pioneering work of F. Drake in 1960, one year after the historical SETI paper by Cocconi and Morrison. This talk explains that SETI evolves with two bases of science; the understanding of our universe and the development of technology. Since SETI has had strong connection with radio astronomy from its early beginning, the impacts of radio astronomical findings and technological breakthrough can be seen in many aspects of the SETI history. Topics of this talk include the detection of microwave 3 K background radiation in the universe. Interstellar atomic and molecular lines found in radio-wave spectra provide the evidence of pre-biotic chemical evolution in such region. Radio telescope imaging and spectral technique are closely associated with methodology of SETI. Topics of the talk extend to new Allen Telescope Array and projected Square Kilometer Array. Recent optical SETI and the discoveries of extra solar planets are also explained. In the end, the recent understanding of our universe is briefly introduced in terms of matter, dark matter and dark energy. Even our understanding of the universe has been evolutionarily revolved and accumulated after 1960, we must recognize that our universe is still poorly understood and that astronomy and SETI are required to proceed hand in hand.     

How many scientists does it take to change a paradigm?: New ideas to explain scientific observations are everywhere—we just need to learn how to see them

The scientific process requires a critical attitude towards existing hypotheses and obvious explanations. Teaching this mindset to students is both important and challenging.People who read about scientific discoveries might get the misleading impression that scientific research produces a few rare breakthroughs—once or twice per century—and a large body of ‘merely incremental'' studies. In reality, however, breakthrough discoveries are reported on a weekly basis, and one can cite many fields just in biology—brain imaging, non-coding RNAs and stem cell biology, to name a few—that have undergone paradigm shifts within the past decade.The truly surprising thing about discovery is not just that it happens at a regular pace, but that most significant discoveries occurred only after the scientific community had already accepted another explanation. It is not merely the accrual of new data that leads to a breakthrough, but a willingness to acknowledge that a problem that is already ‘solved'' might require an entirely different explanation. In the case of breakthroughs or paradigm shifts, this new explanation might seem far-fetched or nonsensical and not even worthy of serious consideration. It is as if new ideas are sitting right in front of everyone, but in their blind spots so that only those who use their peripheral vision can see them.Scientists do not all share any single method or way of working. Yet they tend to share certain prevalent attitudes: they accept ‘facts'' and ‘obvious'' explanations only provisionally, at arm''s length, as it were; they not only imagine alternatives, but—almost as a reflex—ask themselves what alternative explanations are possible.When teaching students, it is a challenge to convey this critical attitude towards seemingly obvious explanations. In the spring semester of 2009, I offered a seminar entitled The Process of Scientific Discovery to Honours undergraduate students at the University of Illinois-Chicago in the USA. I originally planned to cover aspects of discovery such as the impact of funding agencies, the importance of mentoring and hypothesis-driven as opposed to data-driven research. As the semester progressed, however, my sessions moved towards ‘teaching moments'' drawn from everyday life, which forced the students to look at familiar things in unfamiliar ways. These served as metaphors for certain aspects of the process by which scientists discover new paradigms.For the first seven weeks of the spring semester, the class read Everyday Practice of Science by Frederick Grinnell [1]. During the discussion of the first chapter, one of the students noted that Grinnell referred to a scientist generically as ‘she'' rather than ‘he'' or the neutral ‘he or she''. This use is unusual and made her vaguely uneasy: she wondered whether the author was making a sexist point. Before considering her hypothesis, I asked the class to make a list of assumptions that they took for granted when reading the chapter, together with the possible explanations for the use of ‘she'' in the first chapter, no matter how far-fetched or unlikely they might seem.For example, one might assume that Frederick Grinnell or ‘Fred'' is from a culture similar to our own. How would we interpret his behaviour and outlook if we knew that Fred came from an exotic foreign land? Another assumption is that Fred is male; how would we view the remark if we discover that Frederick is short for Fredericka? We have equally assumed that Fred, as with most humans, wants us to like him. Instead, perhaps he is being intentionally provocative in order to get our attention or move us out of our comfort zone. Perhaps he planted ‘she'' as a deliberate example for us to discuss, as he does later in the second chapter, in which he deliberately hides a strange item in plain sight within one of the illustrations in order to make a point about observing anomalies. Perhaps the book was written not by Fred but by a ghost writer? Perhaps the ‘she'' was a typo?The truly surprising thing about discovery is […] that most significant discoveries occurred only after the scientific community had already accepted another explanationLooking for patterns throughout the book, and in Fred''s other writing, might persuade us to discard some of the possible explanations: does ‘she'' appear just once? Does Fred use other unusual or provocative turns of phrase? Does Fred discuss gender bias or sexism explicitly? Has anyone written or complained about him? Of course, one could ask Fred directly what he meant, although without knowing him personally, it would be difficult to know how to interpret his answer or whether to take his remarks at face value. Notwithstanding the answer, the exercise is an important lesson about considering and weighing all possible explanations.Arguably, the most prominent term used in science studies is the notion of a ‘paradigm''. I use this term with reluctance, as it is extraordinarily ambiguous. For example, it could simply refer to a specific type of experimental design: a randomized, placebo-controlled clinical trial could be considered a paradigm. In the context of science studies, however, it most often refers to the idea of large-scale leaps in scientific world views, as promoted by Thomas Kuhn in The Structure of Scientific Revolutions [2]. Kuhn''s notion of a paradigm can lead one to believe—erroneously in my opinion—that paradigm shifts are the opposite of practical, everyday scientific problem-solving.A paradigm is recognized by the set of assumptions that an observer might not realize he or she is making…Instead, I propose here a definition of ‘paradigm'' that emphasizes not the nature of the problem, the type of discovery or the scope of its implications, but rather the psychology of the scientist. A scientist viewing a problem or phenomenon resides within a paradigm when he or she does not notice, and cannot imagine, that an alternative way of looking at things needs to be considered seriously. Importantly, a paradigm is not a viewpoint, model, interpretation, hypothesis or conclusion. A paradigm is not the object that is viewed but the lenses through which it is viewed. A paradigm is recognized by the set of assumptions that an observer might not realize he or she is making, but which imply many automatic expectations and simultaneously prevent the observer from seeing the issue in any other fashion.For example, the teacher–student paradigm feels natural and obvious, yet it is merely set up by habit and tradition. It implies lectures, assignments, grades, ways of addressing the professor and so on, all of which could be done differently, if we had merely thought to consider alternatives. What feels most natural in a paradigm is often the most arbitrary. When we have a birthday, we expect to have a cake with candles, yet there is no natural relationship at all between birthdays, cakes and candles. In fact, when something is arbitrary or conventional yet feels entirely natural, that is an important clue that a paradigm is present.It is certainly natural for people to colour their observations according to their expectations: “To a man with a hammer, everything looks like a nail,” as Mark Twain put it. However, this is a pitfall that scientists (and doctors) must try hard to avoid. When I was a first-year medical student at Albert Einstein College of Medicine in New York City, we took a class on how to approach patients. As part of this course, we attended a session in which a psychiatrist interviewed a ‘normal, healthy old person'' in order to understand better the lives and perspectives of the elderly.A man came in, and the psychiatrist began to ask him some benign questions. After about 10 minutes, however, the man began to pause before answering; then his answers became terse; then he said he did not feel well, excused himself and abruptly left the room. The psychiatrist continued to lecture to the students for another half-hour, analysing and interpreting the halting responses in terms of the emotional conflicts that the man was experiencing. ‘Repression'', ‘emotional blocks'', and ‘reaction formation'' were some of the terms bandied about.However, unbeknown to the class, the man had collapsed just on the other side of the classroom door. Two cardiologists happened to be walking by and instantly realized the man was having an acute heart attack. They instituted CPR on the spot, but the man died within a few minutes.The psychiatrist had been told that the man was healthy, and thus interpreted everything that he saw in psychological terms. It never entered his mind that the man might have been dying in front of his eyes. The cardiologists saw a man having a heart attack, and it never entered their minds that the man might have had psychological issues.The movie The Sixth Sense [3] resonated particularly well with my students and served as a platform for discussing attitudes that are helpful for scientific investigation, such as “keep an open mind”, “reality is much stranger than you can imagine” and “our conclusions are always provisional at best”. Best of all, The Sixth Sense demonstrates the tension that exists between different scientific paradigms in a clear and beautiful way. When Haley Joel Osment says, “I see dead people,” does he actually see ghosts? Or is he hallucinating?…when scientists reach a conclusion, it is merely a place to pause and rest for a moment, not a final destinationIt is important to emphasize that these are not merely different viewpoints, or different ways of defining terms. If we argued about which mountain is higher, Everest or K2, we might disagree about which kind of evidence is more reliable, but we would fundamentally agree on the notion of measurement. By contrast, in The Sixth Sense, the same evidence used by one paradigm to support its assertion is used with equal strength by the other paradigm as evidence in its favour. In the movie, Bruce Willis plays a psychologist who assumes that Osment must be a troubled youth. However, the fact that he says he sees ghosts is also evidence in favour of the existence of ghosts, if you do not reject out of hand the possibility of their existence. These two explanations are incommensurate. One cannot simply weigh all of the evidence because each side rejects the type of evidence that the other side accepts, and regards the alternative explanation not merely as wrong but as ridiculous or nonsensical. It is in this sense that a paradigm represents a failure of imagination—each side cannot imagine that the other explanation could possibly be true, or at least, plausible enough to warrant serious consideration.The failure of imagination means that each side fails to notice or to seek ‘objective'' evidence that would favour one explanation over the other. For example, during the episodes when Osment saw ghosts, the thermostat in the room fell precipitously and he could see his own breath. This certainly would seem to constitute objective evidence to favour the ghost explanation, and the fact that his mother had noticed that the heating in her apartment was erratic suggests that the temperature change was not simply another imagined symptom. But the mother assumed that the problem was in the heating system and did not even conceive that this might be linked to ghosts—so the ‘objective'' evidence certainly was not compelling or even suggestive on its own.Osment did succeed eventually in convincing his mother that he saw ghosts, and he did it in the same way that any scientist would convince his colleagues: namely, he produced evidence that made perfect sense in the context of one, and only one, explanation. First, he told his mother a secret that he said her dead mother had told him. This secret was about an incident that had occurred before he was born, and presumably she had never spoken of it, so there was no obvious way that he could have learned about it. Next, he told her that the grandmother had heard her say “every day” when standing near her grave. Again, the mother had presumably visited the grave alone and had not told anyone about the visit or about what was said. So, the mother was eventually convinced that Osment must have spoken with the dead grandmother after all. No other explanation seemed to fit all the facts.Is this the end of the story? We, the audience, realize that it is possible that Osment had merely guessed about the incidents, heard them second-hand from another relative or (as with professional psychics) might have retold his anecdotes whilst looking for validation from his mother. The evidence seems compelling only because these alternatives seem even less likely. It is in this same sense that when scientists reach a conclusion, it is merely a place to pause and rest for a moment, not a final destination.Near the end of the course, I gave a pop-quiz asking each student to give a ‘yes'' or ‘no'' answer, plus a short one-sentence explanation, to the following question: Donald Trump seems to be a wealthy businessman. He dresses like one, he has a TV show in which he acts like one, he gives seminars on wealth building and so on. Everything we know about him says that he is wealthy as a direct result of his business activities. On the basis of this evidence, are we justified in concluding that he is, in fact, a wealthy businessman?About half the class said that yes, if all the evidence points in one direction, that suffices. About half the class said ‘no'', the stated evidence is circumstantial and we do not know, for example, what his bank balance is or whether he has more debt than equity. All the evidence we know about points in one direction, but we might not know all the facts.Even when looked at carefully, not every anomaly is attractive enough or ‘ripe'' enough to be pursued when first noticedHow do we know whether or not we know all the facts? Again, it is a matter of imagination. Let us review a few possible alternatives. Maybe his wealth comes from inheritance rather than business acumen; or from silent partners; or from drug running. Maybe he is dangerously over-extended and living on borrowed money; maybe his wealth is more apparent than real. Maybe Trump Casinos made up the role of Donald Trump as its symbol, the way McDonald''s made up the role of Ronald McDonald?Several students complained that this was a ridiculous question. Yet I had posed this just after Bernard Madoff''s arrest was blanketing the news. Madoff was known as a billionaire investor genius for decades and had even served as the head of the Securities and Exchange Commission. As it turned out, his money was obtained by a massive Ponzi scheme. Why was Madoff able to succeed for so long? Because it was inconceivable that such a famous public figure could be a common con man and the people around him could not imagine the possibility that his livelihood needed to be scrutinized.To this point, I have emphasized the benefits of paying attention to anomalous, strange or unwelcome observations. Yet paradoxically, scientists often make progress by (provisionally) putting aside anomalous or apparently negative findings that seem to invalidate or distract from their hypothesis. When Rita Levi-Montalcini was assaying the neurite-promoting effects of tumour tissue, she had predicted that this was a property of tumours and was devastated to find that normal tissue had the same effects. Only by ‘ignoring'' this apparent failure could she move forward to characterize nerve growth factor and eventually understand its biology [4].Another classic example is Huntington disease—a genetic disorder in which an inherited alteration in the gene that encodes a protein, huntingtin, leads to toxicity within certain types of neuron and causes a progressive movement disorder associated with cognitive decline and psychiatric symptoms. Clinicians observed that the offspring of Huntington disease patients sometimes showed symptoms at an earlier age than their parents, and this phenomenon, called ‘genetic anticipation'', could affect successive generations at earlier and earlier ages of onset. This observation was met with scepticism and sometimes ridicule, as everything that was known about genetics at the time indicated that genes do not change across generations. Ascertainment bias was suggested as a much more probable explanation; in other words, once a patient is diagnosed with Huntington disease, their doctors will look at their offspring much more closely and will thus tend to identify the onset of symptoms at an earlier age. Eventually, once the detailed genetics of the disease were understood at the molecular level, it was shown that the structure of the altered huntingtin gene does change. Genetic anticipation is now an accepted phenomenon.…in fact, schools teach a lot about how to test hypotheses but little about how to find good hypotheses in the first placeWhat does this teach us about discovery? Even when looked at carefully, not every anomaly is attractive enough or ‘ripe'' enough to be pursued when first noticed. The biologists who identified the structure of the abnormal huntingtin gene did eventually explain genetic anticipation, although they set aside the puzzling clinical observations and proceeded pragmatically according to their (wrong) initial best-guess as to the genetics. The important thing is to move forward.Finally, let us consider the case of Grigori Perelman, an outstanding mathematician who solved the Poincaré Conjecture a few years ago. He did not tell anyone he was working on the problem, lest their ‘helpful advice'' discourage him; he posted his historic proof online, bypassing peer-reviewed journals altogether; he turned down both the Fields Medal and a million dollar prize; and he has refused professorial posts at prestigious universities. Having made a deliberate decision to eschew the external incentives associated with science as a career, his choices have been written off as examples of eccentric anti-social behaviour. I suggest, however, that he might have simply recognized that the usual rules for success and the usual reward structure of the scientific community can create roadblocks, which had to be avoided if he was to solve a supposedly unsolvable problem.If we cannot imagine new paradigms, then how can they ever be perceived, much less tested? It should be clear by now that the ‘process of scientific discovery'' can proceed by many different paths. However, here is one cognitive exercise that can be applied to almost any situation. (i) Notice a phenomenon, even if (especially if) it is familiar and regarded as a solved problem; regard it as if it is new and strange. In particular, look hard for anomalous and strange aspects of the phenomenon that are ignored by scientists in the field. (ii) Look for the hidden assumptions that guide scientists'' thinking about the phenomenon, and ask what kinds of explanation would be possible if the assumptions were false (or reversed). (iii) Make a list of possible alternative explanations, no matter how unlikely they seem to be. (iv) Ask if one of these explanations has particular appeal (for example, if it is the most elegant theoretically; if it can generalize to new domains; and if it would have great practical impact). (v) Ask what kind of evidence would allow one to favour that hypothesis over the others, and carry out experiments to test the hypothesis.The process just outlined is not something that is taught in graduate school; in fact, schools teach a lot about how to test hypotheses but little about how to find good hypotheses in the first place. Consequently, this cognitive exercise is not often carried out within the brain of an individual scientist. Yet this creative tension happens naturally when investigators from two different fields, who have different assumptions, methods and ways of working, meet to discuss a particular problem. This is one reason why new paradigms so often emerge in the cross-fertilization of different disciplines.There are of course other, more systematic ways of searching for hypotheses by bringing together seemingly unrelated evidence. The Arrowsmith two-node search strategy [5], for instance, is based on distinct searches of the biomedical literature to retrieve articles on two different areas of science that have not been studied in relation to each other, but that the investigator suspects might be related in some fashion. The software identifies common words or phrases, which might point to meaningful links between them. This is but one example of ‘literature-based discovery'' as a heuristic technique [6], and in turn, is part of the larger data-driven approach of ‘text mining'' or ‘data mining'', which looks for unusual, new or unexpected patterns within large amounts of observational data. Regardless of whether one follows hypothesis-driven or data-driven models of investigation, let us teach our students to repeat the mantra: ‘odd is good''!? Open in a separate windowNeil R Smalheiser     

Approximations, idealizations and 'experiments' at the physics-biology interface

This paper, which is based on recent empirical research at the University of Leeds, the University of Edinburgh, and the University of Bristol, presents two difficulties which arise when condensed matter physicists interact with molecular biologists: (1) the former use models which appear to be too coarse-grained, approximate and/or idealized to serve a useful scientific purpose to the latter; and (2) the latter have a rather narrower view of what counts as an experiment, particularly when it comes to computer simulations, than the former. It argues that these findings are related; that computer simulations are considered to be undeserving of experimental status, by molecular biologists, precisely because of the idealizations and approximations that they involve. The complexity of biological systems is a key factor. The paper concludes by critically examining whether the new research programme of 'systems biology' offers a genuine alternative to the modelling strategies used by physicists. It argues that it does not.     

Same-Sex Avoidance Relations and What They Reveal about Male Competition

Avoidance relations between male kin are a pervasive social phenomenon, yet the subject has received comparatively little treatment in the anthropological literature. When anthropologists have addressed it, they have usually done so indirectly, or put forward theories better suited to explaining other social phenomena. The most common explanations one comes across in the anthropological literature to account for avoidance relationships between male kin, or what I also describe as same-sex avoidance relations in the paper, are the incest taboo and Radcliffe-Brown's theory of respect. In contrast to these explanations, I propose to demonstrate that the reason male kin avoid each other in certain types of settings is not just to maintain a sense of authority and precedence as Radcliffe-Brown's theory implies, or to avoid contravening incest prohibitions, which as Robert Lowie pointed out long ago is incorrect. Rather, because closely related male kin should not compete with each other, as this would contravene the ideology of descent which demands loyalty to one's kin.     

Synergistic selection between ecological niche and mate preference primes diversification

The ecological niche and mate preferences have independently been shown to be important for the process of speciation. Here, we articulate a novel mechanism by which ecological niche use and mate preference can be linked to promote speciation. The degree to which individual niches are narrow and clustered affects the strength of divergent natural selection and population splitting. Similarly, the degree to which individual mate preferences are narrow and clustered affects the strength of divergent sexual selection and assortative mating between diverging forms. This novel perspective is inspired by the literature on ecological niches; it also explores mate preferences and how they may contribute to speciation. Unlike much comparative work, we do not search for evolutionary patterns using proxies for adaptation and sexual selection, but rather we elucidate how ideas from niche theory relate to mate preference, and how this relationship can foster speciation. Recognizing that individual and population niches are conceptually and ecologically linked to individual and population mate preference functions will significantly increase our understanding of rapid evolutionary diversification in nature. It has potential to help solve the difficult challenge of testing the role of sexual selection in the speciation process. We also identify ecological factors that are likely to affect individual niche and individual mate preference in synergistic ways and as a consequence to promote speciation. The ecological niche an individual occupies can directly affect its mate preference. Clusters of individuals with narrow, differentiated niches are likely to have narrow, differentiated mate preference functions. Our approach integrates ecological and sexual selection research to further our understanding of diversification processes. Such integration may be necessary for progress because these processes seem inextricably linked in the natural world.     

Unusual fungal niches

Fungi are found in all aerobic ecosystems, colonizing a diversity of substrates and performing a wide diversity of functions, some of which are not well understood. Many spices of fungi are cosmopolitan and generalists or habitats. Unusual fungal niches are habitats where extreme conditions would be expected to prevent the development of a mycobiota. In this review we describe five unusual fungal habitats in which fungi occupy poorly understood niches: Antarctic dry valleys, high Arctic glaciers, salt flats and salterns, hypersaline microbial mats and plant trichomes. Yeasts, black yeast-like fungi, melanized filamentous species as well as representatives of Aspergillus and Penicillium seem to be dominant among the mycobiota adapted to cold and saline niches. Plant trichomes appear to be a taxa. The advent of new sequencing technologies is helping to elucidate the microbial diversity in many ecosystems, but more studies are needed to document the functional role of fungi in the microbial communities thriving in these unusual environments.     

The role of pollinators in floral diversification in a clade of generalist flowers

Pollinator‐mediated evolutionary divergence has seldom been explored in generalist clades because it is assumed that pollinators in those clades exert weak and conflicting selection. We investigate whether pollinators shape floral diversification in a pollination generalist plant genus, Erysimum. Species from this genus have flowers that appeal to broad assemblages of pollinators. Nevertheless, we recently reported that it is possible to sort plant species into pollination niches varying in the quantitative composition of pollinators. We test here whether floral characters of Erysimum have evolved as a consequence of shifts among pollination niches. For this, we quantified the evolutionary lability of the floral traits and their phylogenetic association with pollination niches. As with pollination niches, Erysimum floral traits show weak phylogenetic signal. Moreover, floral shape and color are phylogenetically associated with pollination niche. In particular, plants belonging to a pollination niche dominated by long‐tongued large bees have lilac corollas with parallel petals. Further analyses suggest, however, that changes in color preceded changes in pollination niche. Pollinators seem to have driven the evolution of corolla shape, whereas the association between pollination niche and corolla color has probably arisen by lilac‐flowered Erysimum moving toward certain pollination niches for other adaptive reasons.