When learning about evolution, every biology student has been taught, since the modern synthesis of natural selection, that mutation of DNA leads to variation that can then be selected on. But how does a random mutation lead to innovation? This process sounds like it might be very slow, even given the ancient age of the earth. How can such small changes create new things? In a great, albeit very dense and intense book, Andreas Wagner (Professor of Evolutionary Biology at the University of Zurich) answers these and many more questions.
 
In “Arrival of the Fittest” Wagner goes to great lengths to take the reader, in a much better way than I can reproduce here, through his ideas about how nature is set up to supercharge evolution. The authors premise is that of a ‘Universal Library’ where every conceivable combination of something can exist. In such a library a single item, be it a DNA code, the sequence of amino acids in a protein or a metabolic pathway, is connected via single changes (in any one of its parts) to other items in the library. Some, in fact probably many of these versions in the library, are useless/defunct in the sense that they would not work in the real world and so any organism that possess them would not survive. However, many of these versions are perfectly viable and so an organism would be able to survive if it had that copy.
 
Using large computer models in these libraries it is possible to move through them by making single changes that do not disrupt the function of the thing you are interested in (be it DNA, protein or metabolism). Following the logic laid down as you go through the book it becomes clear that there are clear pathways through DNA to protein to metabolic pathways. There are even multiple pathways from any one point in the library to any other point (that still gives the same end result) but when the start and end points are compared on their nucleotide/amino acid/enzyme combination level they are completely different. In effect there are many ways to solve the same problem and they are connected in many ways via simple, singular step changes.
 
Not only can the same processes easily be conserved with this logic but new processes are easily made, as these Universal Libraries contain every conceivable combination. Wagner shows that new metabolic pathways can easily be made, allowing for the exploitation of new food stuffs, without loss of function occurring. The amazing thing is that there are huge numbers of these pathways that criss-cross these libraries.
 
These theories show that life processes are robust and that it creates genotype networks which, in Wagner’s words “enable innovation, the very kind that allow life to cope with environmental change, increase its complexity, and so on, in an ascending spiral of ever-increasing innovability.”.
 
I have probably done a very bad job of trying to convey the ideas in this book, but hopefully I have peaked your interest enough to go out an read it, which I definitely recommend (there is a reason that Wagner has been paid to write a book and I haven’t!).
 
This book has genuinely made me look at evolution from a novel perspective, and these revolutionary ideas show how the power of modern computing can be incorporated into evolutionary biology with breath-taking results.

Recently we’ve all been told that this is the Anthropocene, an age where human impact will be detectable in the ages to come. Much of what this idea encapsulates and is written about in the media is to do with habitat destruction, species loss and climate change but in addition to these and really because of these we are also impacting on the evolution of the species that live with us. Evolution by natural selection leads to the individuals of a species best adapted to that specific environment to survive for longer and reproduce more than those less well adapted. The big thing here is that we, humans, are changing that environment and therefore the direction of selection.
 
Like Darwin, I’ll start with an obvious example of how we have affected the evolution of species: domestication.  Cows, sheep, pigs, chickens et al. resemble their wild ancestors but in many ways are very different. These animals now produce more meat, lactate more and are a lot more docile than their progenitors. This isn’t just something that we’ve done to animals but also plant: modern wheat looks very different from the grasses that hybridised to produce its ancestor and maize is hugely different from teosinte. Since the advent of agriculture, humans have selectively bred the plants and animals with the characteristics they desired the most and this has even happened with pets, leading to some ridiculous breeds.
 
All of the examples above are ways that humans have influenced evolution either intentionally or in ways that we’ve directly benefited from. Another common example that is often in the press, but which we don’t benefit from, is antibiotic resistance. Through our use of antibiotics to prevent and cure infections and diseases we have created a huge selection pressure on pathogens, specifically bacteria, to develop resistance to these drugs. This has resulted in antibiotic resistance. We’ve changed the environment and created a massive advantage to those individuals whose mutations convey resistance. This is evolution on super drive, as bacteria reproduce rapidly, one bacteria could produce a billion descendants in 10 hours (if conditions are right), and can transfer genes between species, further accelerating the process.
 
Human activity is directly impacting on the evolutionary trajectories of species that are much bigger than bacteria. Humans are a super predator, able to take large numbers of a species at a fast rate and not switching when their numbers fall. This form of predation creates a huge selective pressure on the prey species to change. Atlantic cod, the species that Brits prefer as part of our fish’n’chips used to be over 2m long. By removing large fish, through commercial fishing, we’ve created an environment were being smaller and reaching sexual maturity earlier is optimal. This human induced change in the environment has led to cod evolving to be smaller and that males are becoming sexually mature earlier. But this doesn’t just mean that our fish’n’chips will decrease in size (it’s not a Tory plot) but it changes the whole ecosystem as cod’s place in the food chain will change, now becoming prey when it once was a predator.
 
Predation doesn’t just impact the evolution of the species we exploit commercially but also those that we hunt for fun. This is something that I’ve seen first-hand while working in South Africa. We shot antelope on our ‘farm’ solely for food, and as such just took the first ones we found (if they weren’t pregnant). As such, our male springbok hand lovely big, symmetrical horns, because the predation pressure was in effect random. Our neighbours, who often had trophy hunters pay to come onto their property and pay to shoot males with big horns had male springbok with smaller, less impressive horns (even when of comparable size). By selectively shooting males with large horns humans had produced a change in the predation regime that made having big horns very costly and so selected for males with smaller horns. This isn’t just anecdote; trophy hunting has been shown to have reduced the size of bighorn sheep’s horns by about 25%. This isn’t just an impact on the physical appearance of males but also of the way that mate selection takes place. Prof David Coltman, author of this research, explains: "The crux here is that the horns develop to the length where they can be legally harvested several years before they achieve social dominance. So in effect they're being harvested from the population before they can reproduce and pass their genes on."
 
Urban environments are not devoid of nature. Many bird species are common in towns and cities throughout the world. However, living in a habitat that differs so much from the one that these species have evolved in has led to many behavioural and physiological changes. One of the obvious ones is that bird song in urban areas differs to the song of the same species in more ‘natural’ habitats. Birds sing at different times, even at night, to avoid noise interference. The actual acoustic structure of bird song has also changed in urban environments, and this is a crucial aspect of not just mate selection but territorial behaviour in many of these species. The optimal behaviour of a species in an urban area can be different to that of individuals of the same species in wilder areas, urban birds may not migrate like their ‘wilder’ brethren and this is an anthropogenically driven adaptation. An finally, urban areas may act like islands because they are invaded by a small number of individuals of a species creating founder effects but also because urban individuals do not regularly breed with their wild neighbours, effectively isolating themselves off. This has happened in the European blackbird and resulted in reduced genetic diversity of urban populations but also resulted in physical differences between urban and rural birds.
 
Adding to all of this is the increased movement that human activity has allowed certain species. This has meant that species can move between continents like never before, creating novel ecosystem assemblages and interactions. The presence of alien species, which are often well adapted to human disturbed environments, offers new unexplored avenues for evolution to try out. This is a lot more speculative than the previous paragraphs, but new mutualisms, host-parasite relationships and even hybrids may be created because humans have allowed animals and plants to move further and faster than ever before.
 
This is both fascinating and frightening at the same time. But without studying these impacts it is not possible to gauge how we can reduce/stop them, or even enter a debate into whether we need to intervene at all? Are we not just another part of the environment?

​This is a bit of a speculative and potentially rambling post after a discussion that I had last night gave me an idea. This will mostly involve me using my own knowledge to think around a subject, potentially coming up with an idea that someone else has already had. But hey, sometimes you need to just think around a topic to get ideas.
 
My idea is about sexual selection and colour vision. Birds often have dazzlingly bright plumage, in the case of species like peacocks or birds-of-paradise, or use colourful object in their displays, such as bowerbirds. Typically it is the male who is showy (potentially attracting predators), whilst the female is more cryptic (hopefully avoiding predators), something that was obvious to the person who named widow birds. Frogs and reptiles can also be brightly coloured, for example the Augrabies agama with their brightly coloured bobbing heads. Mammals on the other hand don’t really go in for bright colours, when you think of sexual selection in mammals it is often massive males fighting, be they bighorn sheep smashing into each other or elephant seals on an Antarctic beach. The obvious exceptions are primates, with bright anogenital swellings in baboons and the suave faces of mandrills.
 
Why might there be bright colouration for sexual selection in birds, amphibians, fish and reptiles but not in mammals? One obvious answer is that mammals typically have poor colour vision, with an obvious exception of the primates. How can a bright colour display work if the individuals you need to receive it are unable to detect the signal? Mammals seem to have lost the ancestral colour detection systems that all the other vertebrates retain, potentially because they took up a nocturnal niche and relaxed selection meant that it was lost. But since the dinosaurs died mammals have come out of the shadows and many of them are diurnal (like birds etc.), so why no showy colours if they’re out in the sun? It may be that without the ability for natural selection to explore the avenue of colour in mate choice that male-male aggressive competition was the sole mechanism for sexual selection to use. Maybe once you’ve gone far enough down this route it is difficult for evolution to backtrack, i.e. going down a fitness gradient. This is my own little idea, developed on a Sunday night. However, in primates colour vision has reappeared (as it has in a number of other mammal groups too), some researchers think this was to detect ripe fruit, and in this group colour has become part of mate selection.
 
It’s really interesting to think that an evolutionary quirk, the fact that mammals seemingly lost their colour vision has had a big impact on how their sexual selection systems have evolved and simultaneously their social systems. Evolution can only work with what it has, and this may be a nice example of how the loss of one characteristic can have a large impact on a seemingly unrelated aspect of evolution. But potentially the same selection pressures that lead to losing colour vision may have pushed the development of smell, and mammals are masters of the olfactory realm. Ironically, as we are mammals, it may be our own preclusion for the visual world that prevents us from appreciating the diversity and intricacy of sexual selection via odour in mammals.

I’ve not blogged for a while because the Rugby World Cup has become an all-consuming part of my life. But I thought that I would try and take a break from rugby and write a little bit about some cool science that has come out recently.

Firstly, a new pied babbler paper by Martha Nelson-Flower. This new study has found that, unlike for females, male-male competition is not costly for the dominant male in pied babbler groups. Pied babblers groups are typically highly kin structured, with only the dominant pair being unrelated and so able to breed. But when a subordinate male is unrelated to the dominant female he is able to compete to breed. However, this new study has found that in these situations do arise there is almost no cost to the dominant male: it doesn’t affect the number of successful nests, the number of fledglings fathered by the dominant or his chances of retaining his position. This is in stark contrast to the cost of female competition in this species. When two females are able to breed it delays the onset of breeding, reduces the number of successful breeding attempts and results in females destroying each other’s eggs. Taken together, these two studies show a drastic difference in intrasexual competition in this species that has a huge impact on the group dynamics and evolution of sociality. It also strengthens the arguments put forward about why female fledglings are so much more aggressive than their brothers!

New paper (male-male competition): Male-male competition is not costly to dominant males in a cooperatively breeding bird. Behavioural Ecology and Sociobiology

Old paper (female-female competition): Costly reproductive competition between females in a monogamous cooperatively breeding bird. Proceedings of the Royal Society London B

Secondly, researchers looking at the morphology of Rocky Mountain bees have found that over the last 40 years their tongues have gotten shorter. They suggest that this is due to the changes in flower distribution and abundance brought on by climate change. Because drier weather is reducing the number of flowers, bees have to work harder to find nectar and so bees with traits best suited to the new environment are favoured. It’s amazing to see evolution in action, in a similar way to Claire Spottiswoode’s work on honey guides.

Bee paper: Functional mismatch in a bumble bee pollination mutualism under climate change. Science

The study’s lead author Nicole Miller-Struttmann suggest the reason for the direction of evolution are that “It would take longer to find the deep flowers, so the longer-tongued bees are going to spend more time searching. But if you’re a generalist, short-tongued bee, you’re more likely to run into your resource.”

It's something that every child wonders at some point while splashing around in the bath or at a swimming pool: 'Why are my fingers all wrinkly?' The rest of your skin stays pretty much the same after a prolonged soak but your hands and feet take on prune like characteristics. I always assumed that your hands just absorbed the water and that caused the problem. I formulated this opinion before I knew much about biology and never really scrutinized this idea, which really doesn't stand up to much scrutinization.

But a cool bit of research (abstract below) has found that it's all to do with being able to handle wet objects better.WE have evolved a mechanism for improving how do things in the wet. Water being absorbed into the fingers isn't even a part of this phenomenon, as it's actually driven by the autonomic nervous system.The authors of the paper talk about theories as to why we don't have wrinkled fingers more often but the question I find interesting is why do we have them at all? Surely results like this tell us about our evolutionary past and the environments in which our ancestors lived and foraged. I have no idea if chimps, gorillas or orangutans have this adaptation. If they don't then it suggests it evolved after we diverged from our closest relatives. Ideas about humans foraging along the seashore have been a big part of understanding how humans evolved and spread out of Africa, so maybe this finding a clue to that? 

A lot of this post is speculation, but that's the part of science that drives future areas of research and the joy of think about 'why?' is what I love so much about science.

Abstract:


Kareklas et al. (2013) Water-induced finger wrinkles improve handling of wet objects. Biology Letters 
DOI: 10.1098/rsbl.2012.0999
Upon continued submersion in water, the glabrous skin on human hands and feet forms wrinkles. The formation of these wrinkles is known to be an active process, controlled by the autonomic nervous system. Such an active control suggests that these wrinkles may have an important function, but this function has not been clear. In this study, we show that submerged objects are handled more quickly with wrinkled fingers than with unwrinkled fingers, whereas wrinkles make no difference to manipulating dry objects. These findings support the hypothesis that water-induced finger wrinkles improve handling submerged objects and suggest that they may be an adaptation for handling objects in wet conditions.
http://rsbl.royalsocietypublishing.org/content/9/2/20120999

This post is likely to be controversial and contentious. It’s likely that some people may misread it and interpret what I’ve written in the wrong way – so please read it to the end. Therefore, before I go any further I’ll point out that I am a firm believer in sexual equality; both women and men deserve equal pay and opportunities. I see many examples of sexism in the world and they all make me feel ashamed to be male. As I have gotten older I’ve become more attuned to the prejudices that pervade modern British society, as progressive as we like to think it is. There is no but at the end of this statement. This post has been inspired by both my understanding of biology and the fact that I haven’t heard this argument made anywhere else.

Sexism may be a natural state, but that doesn’t make it a morally defensible one. Conflict is rife in the animal world between predators and prey, between males competing over access to female, females competing over access to males and between members of a breeding pair who are raising joint young. Sexual conflict exists in all sexually reproducing species, be they animal or plant. When two individuals aims are not perfectly aligned, as happens for example when a male and female bird decide to breed together, then there will be conflict – over how much each invests in their offspring and even if they decide to stick around to help raise them. Conflict of this kind is theorized to be the reason behind sexual differentiation: the production of one large gamete with lots of resources or lots of smaller ones with fewer resources. This initial difference sets up conflicting interests between the large gamete producers, females, and the small gamete producers, males. Females typically invest heavily in offspring and so want to choose the best sexual partner, whilst males do best by spreading their inexpensive (although there is a cost to sperm production) seed.

But what has this got to do with feminism and misogyny? In modern human societies men are in a position of power. They are paid better, more likely to be employed etc. For society to be equal we are asking for a subset of a species to voluntarily give up a position of strength, but what benefit do they get from doing this? One argument would be that having more women higher up in companies will be good for business, we’ll be promoting purely on merit and so only the best will get to the top. This is likely to be true. But I’m an evolutionary biologist and this way of thinking seems very close to group selection – which we know is not how evolution works. Animals, plants and even people will behaviour in a way that is optimum for them, if this optimum happens to coincide with the optimum for the group then that’s great and then we get cooperation. But the interests of the group or species do not always coincide with the individual. So, individual members of the board of executives are unlikely to voluntarily give up their position to a woman just because the company will do better. Similarly, a male boss is likely to employ a man in his mid-twenties over a woman of similar age because he is less likely to take leave because of a baby, making the life of the boss easier. In behavioural economics experiments people will actually pay so that others will incur a cost (this is called spite). What I am trying to say is that the reason why sexism still exists in modern western society may be because we haven’t come at it from the correct angle, we’ve simply relied upon people behaving in a way that is moral and ethical, which can only get us so far – we’ve not thought about it in an evolutionary way.

Males don’t always have to win - sexual conflicts are not always static. Some species, like elephant seals, have extreme sexual dimorphism (driven by competition between males) and this makes females very week in the interactions of this species (I’ve not studied seals and so his might be a crap example). However, in species like the dunnock, the balance of power between males and females is in constant flux. Sometimes the males win, getting to mate with two females and have twice the number of offspring, and sometimes the females win, getting to mate with two males and have them both help rear her young. I went to a conference where they found that dunnocks in New Zealand actually behaved differently to those in the UK and the outcomes again were in flux. What this shows is that through changing costs and benefits, even the habitat, we can influence sexual conflict and potentially sexism.

It’s very difficult to change the way people behave, but if we can influence the environment in which businesses work and that men and women interact. The He For She campaign is a great idea to changing male behaviour early, but if the benefits of sexism remain in later life it may have limited effect. Another way to change things is to avoid any possibility of sexism. For example, it used to be thought that women couldn’t play the tuba but then orchestras started to have blind auditions and all traces that the player might be a women were cover up. The result was a massive increase in the number of women playing the instrument in orchestras. In the leave due to a baby example I used above, making it possible for men to take as much paternity leave as women can take maternity leave could eliminate the difference in cost to employer – rendering choosing a man the same as choosing a woman. By reposing the question and asking why sexism exists, we can seek to find evolutionary answers that may allow us to put an end to it. 

You may think this is overly simplistic, that we're rational creatures and so above any such 'manipulation' but how much washing up we do is effected by our environment!

This isn't something that I think is particularly new, as Tim Clutton-Brock used to wax lyrical about this during lectures, while wandering the Kalahari desert and also in the tea room. But this new review paper about the Resource Dispersion Hypothesis is still pretty cool. It just highlights the intrinsic link between environment and individual, with it's knock-on effects on sociality and behaviour (behavioural ecology rocks!).

Macdonald & Johnson (2015) Patchwork planet: the resource dispersion hypothesis, society, and the ecology of life. Journal of Zoology, DOI: 10.1111/jzo.12202


Virtually nothing in nature is uniform. Observed at the right scale, most entities are clustered rather than evenly distributed, spatially and temporally, and this applies across domains from the distribution of matter in the universe, to habitats across the Earth's surface, and to energy in the landscape. Patchiness means organisms cannot carve out even territories. Instead, their shape and size depends on the dispersion of materials needed for survival and reproduction. This fundamental feature of life is intrinsically understood in ecology, for example, in the ideal free distribution and optimal foraging theory, and is represented in the anatomy as well as behaviour of organisms via the structures and strategies for moving, finding and capturing these patchy resources. But perhaps most striking of all is the role of patchiness in facilitating the formation of social groups – of societies. The resource dispersion hypothesis (RDH) suggests that where resources are dispersed and rich enough, multiple individuals can collapse into groups that share the same space at little cost to each other. Cooperation may be absent, but sociality is favoured nevertheless. Thirty years after the origin of the hypothesis, we review the accumulating models, critiques, evidence and experiments, concluding that RDH is a pervasive feature of animal spacing patterns across a wide range of species, taxonomic groups and ecosystems. In the spirit of the original objective of the Huxley Reviews to ‘suggest and inspire research that will improve our knowledge in the future’, we also take the opportunity to consider wider implications of the RDH. If we live and evolved on a patchwork planet, then we should expect broader effects. Indeed, we suggest that the RDH has played an important role in the evolution of cooperation, biodiversity, behaviour and, not least, in the social organization of humans in our evolutionary past and today.

http://onlinelibrary.wiley.com/enhanced/doi/10.1111/jzo.12202/?hootPostID=68ee30c1b9bbabb8c53e3d228f01b3ce

This is my attempt at trying to address some of the common misconceptions that I regularly hear from friend, read in the newspapers or see on TV (including some documentaries by famous physicists) about evolution. I think they are important to address, because a lack of understand these aspects not only diminishes our understanding of an amazing concept that has changed the way we understand and look at the world, but also because it opens us up to the encroachment of creationism (which includes ID).

1.       "We’re the pinnacle" 

This misconception is based on the idea that evolution is a linear progression whose ‘purpose’ or ‘end goal’ is the development of the human species. This simply is not how the evolutionary process works, natural selection favours the individuals who are best able to survive and reproduce in the current environment. When environments change the goal posts are shifted and individuals with different characteristics will now survive and reproduce more. As we are all too aware with global warming, environments change and so the evolutionary goal posts are constantly changing. This means that there is never an end point in sight for the evolutionary process, just optimizing for what’s in front of it. A great example of this is the fact that lots of now ‘simple’ worm like species had ancestors that were fairly ‘complex’, the evolutionary goal posts shifted and the ‘simpler’ individuals did better than the more ‘complex’ ones.

2.       "it's just random"

In almost the polar opposite direction to the previous misconception is the one that it’s all just completely random. This misunderstanding has probably arisen due to the use of the word ‘random’ when describing how mutations occur. Mutations are a crucial aspect of evolution; they provide the variation in individuals on which natural selection can act and without it the great diversity of life would never have happened. Mutations are random in the sense that it’s not possible to predict when they will happen, where in the genome they will happen or if they are good or bad. What is not random is whether those mutations will make a difference to the evolution of that species. Most mutations are bad, they occur in genes in a way that makes them no longer work or have a negative effect on an individual’s ability to survive and reproduce, some mutations don’t do anything as they occur in non-coding areas of the genome (although we’re finding out more and more about these areas and they may be important), only a tiny fraction of mutations will result in an individual being better adapted to its environment. So the mutations are random but natural selection is not.

3.       "Species want to get taller" and "It's for the good of the species"

‘Giraffes are tall because they wanted to get taller to eat the leaves at the top of the tree.’ This misconception is from mixing up the end result of the evolutionary process with some sort of conscious decision on the part of the individuals that led up to that point. Firstly, giraffes have long necks for fighting not for eating leaves (although that’s unimportant here). Secondly, the ones with longer necks will be the ones that do have more offspring and there genes will be maintained in the population. But just because we can see the ‘end results’ of the evolutionary process, i.e. the species that exist today, and so can hypothesize and test the driving forces that have led to their current adaptation (ornaments, behaviours and abilities) does not mean that their ancestors were consciously trying to evolve them.

The phrase 'for the good of the species' is used because many people think that all members of the species are striving for the species to keep existing. Unfortunately this idealistic, utopian view of intraspecies harmony is not borne out by our observations of the natural world: infanticide, homicide and inter- and intra-group conflicts. Individuals will do best to maximize the number of their offspring, ensuring that their genes are passed on. Sometimes, due to ecological constraints, like availability of mates to breed with (and a few others), individuals will actually help others (almost always their closest relatives) to breed - cooperative breeding or eusociality. But these situations can always be explained by these individuals either doing the best of a bad job and helping their relatives to breed, kin selection, while they wait for a breeding position to open up for themselves.  

4.       “We’re Just constantly ‘eyeing’ up each other for mates”  or “I can’t help it, I’ve evolved to be this way”

 This is another misconception between intention, behaviour and the evolutionary process. A lot of human behaviour is driven by our unconscious, if we had to think about every single thing we did it would be crazy – I’d have to be thinking about every single muscular movement in my hand as I type rather than using muscle memory. Lots of studies have shown unconscious biases in behaviour that the individuals were not even aware of. Sexual preferences for members of the opposite sex fits easily into that, but it doesn’t mean that you’re some sort of sex drive beast. The humans subconscious is an area that we are only just beginning to understand, from why certain colour placebo pills work better than others to why men tip strippers who are on their period more than those who aren't. There are probably evolutionary reasons for these but they do not define us as individuals, understanding them empowers us as a species. It also does not mean that you can just blame bad behaviour on such things, we are highly conscious individuals and we can rationalise our behaviour and take responsibility for it.

5.       ‘If we evolved, why are there still chimps?’

Chimpanzees are not what humans evolved from, they are our closest relatives. Roughly 2 million years ago there was a species, probably more like modern chimpanzees than us but was not a modern chimpanzee – this is our common ancestor. This species went along two evolutionary trajectories that have living decedents today, one leading to humans and one to chimpanzees, both of which are different from this ancestral species. Humans have common ancestors with every living species on the planet, something that blows my mind, and these species are the points at which we diverged on the evolutionary tree.

This misconception is also influenced by people calling crocodiles ‘living fossils’. Modern crocodiles are very similar to ancient ones, but they are different, they have evolved. Some ancient crocodiles had long legs and could probably run very fast (modern ones can too but only short distances). Things do change over the course of millions of years, it’s just that some (like crocodiles) don’t change quite so much.

If this has either interested you or confused you then I recommend reading Richard Dawkins’ ‘The Ancestors Tale’. It’s a really complete and accessible way of understanding how evolution works and provides a myriad of examples that are used in most university course.