PSY1HAE Topic 4: Adaptation and Domestication PDF

 Topic 4: Adaptation and Domestication as Keys to Understanding Modern Human Animal Relationships ecosystem, a system that is self-sustaining and When you have completed this topic, you will: comprised of i...

 Topic 4: Adaptation and Domestication as Keys to Understanding Modern Human Animal Relationships ecosystem, a system that is self-sustaining and When you have completed this topic, you will: comprised of interactive elements, both living and non-living, as first defined by Tansley (1935). Be familiar with different types of Because all of the elements in an ecosystem interact biological relationships to some extent, different terms have been developed Understand what the word 'adaptation' means and be able to explain how to describe different types of relationships. If you adaptation operates at the level of both think about it, a relationship can either have a individuals and species positive effect, a negative effect, or no effect on the Be able to provide a definition of parties involved in it. If you take these three domestication outcomes and look at all possible combinations, you Understand the biological bases for get a table that looks like the one below. adaptation and domestication of animals and why so few animal species are domesticated Be aware of the idea of domestication genes and the neurochemicals thought to be implicated in 'tameness' Be able to discuss why re-wilding domestic animals and/or domesticating endangered species may not be feasible The main objective in this topic is to put the theoretical material we covered in previous topics into a more concrete intellectual context. We have already considered some of the evolutionary pressures that may have led to the development of modern humans and modern animals, and we have thought about how this might affect the way we now think and behave. In this topic we will examine more closely the processes of adaptation and domestication, and how these processes can result in profound changes in both individual animals and entire species. To some extent, what we have been looking at up until now is WHY humans and animals developed as they did. In this topic we will begin to look at HOW these changes happened. The objective is to encourage you to adopt the view that domestication is something humans have done ‘with’ animals rather than ‘to’ animals. Ecosystems and the relationships within them Biologists have long recognised that no biological As this table shows, there are six basic relationship organisms exist in a totally independent manner. types, ranging from mutualism, where both species Instead, all organisms live embedded within an benefit from the relationship, through to synnecrosis, where both species are negatively affected. Mutually rewarding relationships are common in nature and some biologists believe that all species are involved in at least some of these. For example, ruminant animals like cattle receive nutritional benefits from gut microbes, who can only survive in the ruminant gut. Flowers benefit from the transportation of pollen by bees who feed from plants. Humans also benefit from this relationship, with 15-30% of the food we consume being the product of biotic pollination (Winfree & Kremen, 2009). Relationships that are detrimental to both species are much rarer in the natural world and do not tend to last very long in evolutionary terms, for obvious reasons. There are two reasons why you need to know how to classify biological relationships. The first is that if we are going to explore how humans and animals live together, you need to understand what possible forms these relationships could take. Think about what type of relationship you have with any animals you keep as pets, those you use for their products, and those you watch in nature reserves. Each is likely to be quite distinct. Second, it is important to acknowledge that we cannot manage animals effectively by simply stopping our interactions with them. Some animal rights activists maintain that humans should not eat animals, use them in So how do changes in biological relationships take experiments, or even keep them as pets. However, place? For most of our history we either hunted as long as we live on the same planet we cannot animals or they hunted us, but now some of them withdraw completely from all relationships with co-exist with us. We also wear them, ride them, animals, so a more realistic approach is to say that watch them, and eat them and, as we saw with our we should perhaps change some of our current wolf example in Topic 2, sometimes we spend a relationships, not that there should be none at all. fortune trying to exterminate them and then change Is change possible? A quick look at history makes our minds and spend another fortune trying to it very clear that relationships between humans and protect them. The concept of adaptation explains animals, and also between one animal species and one way in which human-animal relationships form another, are constantly changing. It is not the case and change. that there is a right way for the world to be, with Adaptation at the level of individuals everything lovely and balanced and living in perfect harmony. Nor is it true that this would be the case According to the World English Dictionary, the word if humans did not interfere. The world has always adaptation means ‘something that is changed or been a messy place, with constant change being the modified to suit new conditions or needs’ and, most enduring feature. Sure, humans have caused a specifically in biology, to ‘an inherited or acquired whole lot of changes lately, some of which seem modification in organisms that makes them better catastrophic and irreversible, but change in the suited to survive and reproduce in a particular natural world is constant and we have to keep in environment’. In Topic 3 we considered the ideas of mind that humans are part of the natural world, not E. O. Wilson, who argued that all organisms are something that operates outside its basic laws. born with an expectation regarding what environment they should be in. This is correct, but it is also correct that organisms often find themselves in less than optimal conditions. Adaptation at the individual level is about coping behaviourally. Insects and simpler animals are often with these less-than-ideal conditions. incredibly inflexible. They arrive on earth fully prepared to behave in a certain way and, if this is not It is easy to think of an example of adaptation at the possible, they die. More complex animals tend to be individual level. Imagine that you buy a puppy. more flexible, with humans being the most flexible of When she first arrives at your house, she is likely to all. The downside of this flexibility is a long period of be very poorly adapted to her new environment. She infancy, where young animals are vulnerable while may bark incessantly when she wants attention and they learn to adapt to their less predictable she probably has no control of her bladder or environment. Many animals and many people have bowels, so accidents happen – All. Over. The. House. died, taking their genes with them, because they From a social standpoint, she might think that she were unable to adapt rapidly enough to their was put on earth to run things, including your older environment. A third factor that determines how well dogs, yourself, and the other humans in your home. an animal can adapt is age. Animals that arrive on What would you do with your puppy? One option is earth with a capacity for behavioural plasticity, to buy a one-way ticket back to her breeder. Another including humans, are typically much better at is to help her adapt to her new environment. adapting to new environments when they are young. You could do that initially by managing the situation When complex animals are born their brains are only so that she is safe while she learns about her new partially developed, and how they develop depends home. You may even change the environment on the environment. Once an animal learns what is somewhat, by rolling up the carpets so that puddles required of it, however, it becomes more difficult to on the floor are not such a big problem. You might change. This is why it can be challenging to introduce issue a stern ‘No!’ every time she barks, and pay her adult animals (including humans) to new lots of attention when she is quiet. You could reward environments. her for toileting outside on the grass and ignore accidents in the house. For the first 2-3 weeks there is likely to be absolute bedlam in your house. After that, though, your puppy should start to get the idea that good things happen to her when she behaves in certain ways. After a few months, she should be perfectly well adapted to her environment and generally behaving in ways that make you happy. All your hard work should have paid off. This is a perfect example of individual adaptation, and there are many others. Humans learn to adapt to society by going to school for five days per week. Someone who comes from a different region or culture has to adapt to living in their new home. Adaptation at the level of species Anyone who has tried to break-in a wild horse or tame a feral cat has attempted to help that animal Imagine how beneficial it would be if the adapt to life among humans. In this context, information we learned during our lifetimes could adaptation really just means learning how to act be passed down to our offspring. In our society, this within a certain environment, and all organisms do it is exactly what we are attempting to do when we to a greater or lesser extent. send our children to school for many years. We could not always do this, however, and it was much Importantly, though, there are several factors that more difficult before we had books and television influence how well an organism is able to adapt to a and, more recently, the internet. Other species also given environment. Biological constraints refer to pass information down through generations, fundamental aspects of biology that determine the although they are limited by how well they can kind of environment to which animals are able to communicate and store information. Also, this type adapt. Hens cannot be kept under water, nor can of adaptation is very time consuming and quite risky cows live in a desert, unless we are able to alter the – your offspring could easily die while you are environment to suit their needs. Behavioural teaching it the special skills needed to survive. plasticity refers to how flexible an animal can be Would it would be better if information could be passed down automatically, so that adaptations three key concepts you need to know about to made in one generation are hardwired into the next understand Darwin’s theory of evolution: individual generation? variation, biological fitness, and genetic selection. The concept of individual variation is simple, referring to the fact that every animal within a species is an individual. To an untrained eye, all giraffes might look identical. As you become more familiar with animals, however, you see individual variation in how they look and act. This comes from the genetic material each animal inherits. If you don’t know the basics of genetic transmission, you might like to spend some time at this website. It has tutorials which present information about DNA, genes, chromosomes, heredity and traits. Individual variation is important because it means that some animals are better suited to particular environments than are others. This is called biological fitness. In any natural system those animals less suited to the environment are more likely to get killed, while those that are better suited are more likely to stay alive. These animals are said to be ‘fitter’ in a biological sense. Animals who stay alive for longer are much more likely to pass their particular combination of genetic material down to the next generation, so the traits that made them more suited Jean-Baptiste Lamarck, in the late 1700s, was one of to the environment become more widespread. This is the first scientists to get really excited about called genetic selection and it is an indirect way for evolution, although it turned out that he was mostly an entire population to benefit from past experiences. wrong about how it worked. Lamarck proposed that Those animals that ‘fit’ the environment better are a change in the environment could cause changes in more likely to survive and reproduce – they are the needs of organisms living in that environment, selected by the environment because of their which, in turn, could cause changes in their particular combination of genetic material. behaviour. Because altered behaviour might lead to more or less use of a given structure or organ, he An important concept to grasp is that the traits that argued that such organs might become larger or make some individuals better adapted than others smaller. This is a fairly reasonable conclusion. In in one environment, can be detrimental in another addition, though, he argued that such changes would environment. As an example of this point, you need be heritable, producing gradual but continuous to familiarise yourself with the case of the Peppered changes in how organisms look and act. We now Moth. know that this is not how things work. You can work really hard to develop your muscles or your math ability, but this will not have any direct effect on your children’s muscles or math ability. While Lamarckian inheritance has been discredited, it is now well established that entire species are able to benefit from the experiences of parents and grandparents, although this happens in a fairly indirect manner. This type of adaptation, unlike individual adaptation, takes place over a very long time frame, and is the cornerstone of Charles Darwin’s theory of evolution. You probably already have some familiarity with this theory, but there are This example is drawn from a situation that occurred it contains great information about the basics of just outside London during the industrial revolution. evolution. Prior to the revolution, a species of moth, the Peppered moth, lived in the surrounding forests. Selection by humans as an adaptive force They were fairly light in colour and nicely Humans often alter the effects of natural selection camouflaged against the light bark of the trees, by practicing what is called artificial selection, which which protected them from predation. Every now is exactly the same as natural selection except that and again a dark moth hatched but, because it humans, rather than other parts of nature, are doing stood out against the light-coloured trees, it was the selecting. One really good example of how quickly eaten before it had a chance to pass on its natural and artificial selection can operate together genes. to produce a whole new type of animal is the With the advent of the industrial revolution, factories domestic dog. The first domesticated species was in London started belching out horrible black the wolf/dog. Scientists are not sure why smoke, and the bark of the trees became much domestication happened, but one popular darker. This gave the unusual dark moths a huge explanation is that when humans started living in advantage, whereas the light moths stood out, just groups, they adopted cute little wolf cubs and waiting to be eaten. For a more detailed explanation turned them into pets. of the adaptation of the peppered moth, check this Imagine that you are a child living about 20,000 video out. years ago and you and your friends find a litter of Darwin’s theory of evolution is important because it wolf cubs and take them back to camp. Your parents explains the link between individual variation and complain a little, but eventually give in. You each differences in biological fitness. In his day, nobody keep a cub until they hit puberty. Then things turn had any idea that genes existed, much less how they nasty. All of the wolf cubs start biting people and operated, but he was able to propose that the stealing food, so they are killed or run out of camp. selective process he had observed might explain In some other camp somewhere else the kids do the how species gradually evolve into something same thing, but this time one of the pups doesn’t different. And, most importantly for our purposes, get nasty when it grows up, so she gets to stay. She note that natural selection and individual adaptation goes out and gets pregnant and has her cubs in the work not just on physical traits but also on camp, where they are well socialised with humans. psychological ones and social ones. Our Again, most turn nasty at puberty and are killed, but relationships with other species have changed, and one or two are very placid and these get to live they will continue to change in the future, because happily ever after in the human camp. of natural selection and individual adaptation. In this scenario, pretty soon there could be many wolves able to adapt to living in close proximity to humans, so they might get shared from camp to camp. At the same time, perhaps those humans who liked wolves and encouraged them to stay around also gained some kind of survival advantage. Maybe having wolf/dogs around to clean up human waste prevented disease; maybe having them around gave humans an early warning system for when hostile strangers were approaching; maybe they helped with hunting so that humans with dogs were better fed than other humans. Whatever the reason, perhaps our ancestors who liked wolf/dogs fared If you need to revise evolutionary theory, check out better reproductively than did those who were dog this excellent video. It’s a full-length (50 min) haters, producing lots of little humans who were documentary but it gives you a really good genetically more inclined to like dogs. These children understanding of evolutionary theory if this is then grew up in a social group where dogs were something you are not familiar with. For a much accepted, becoming individually adapted to having shorter introduction to the theory of evolution dogs around. The end result could well be a change watch this video. This is a little bit controversial, but in the wolf-human relationship. Where we once saw wolves as predators or prey, now we see them as selected on the basis of their coat colour and type, companions and allies. Similarly, where they once different coloured coats turned up more and more saw us as competitors, now they see us as friends. frequently, and they also differed in length and This is co-domestication at work. This (less than 10 texture. Tail and ear carriage also changed, and the min) video discusses theory of how the wolf was foxes developed a wider range of vocalisations. domesticated. There were some physiological changes, too: they started having two mating seasons per year rather than one and they were generally far less reactive towards novelty. This shows how selective breeding by humans can have a profound effect on how species look and act, even in a relatively short time. In the case of the foxes, the basic neurochemistry of the brain was altered by human intervention. Maybe similar things happened in the human brain during the process of evolution. For more information about the Belyaev study, check out this recent article in National Geographic about the fox experiment, along with links to photos of the foxes as they look today. Domestication – the process of adapting to a domestic environment One way to describe what happened to Belyaev’s foxes is to say that they became domesticated, following the same pathway as some tame wolves did a few thousand years ago. But if foxes are capable of domestication, why weren’t they domesticated thousands of years ago as well? Archaeological records show that, after wolves were A really amazing example of a canine domestication domesticated some 20,000 – 14,000 years ago, it program involves foxes and a Russian scientist was a long time before any other animal species was named Dmitri Belyaev. Nearly 60 years ago he set living in human camps. Goats and sheep followed up a domestication project with silver foxes, which dogs, with cattle and pigs appearing some 9,000 were kept in Russia for the fur trade. When he began years ago in Asia. By 4,000 years ago, horses, his experiments, all of the foxes looked and acted in camels, buffalo, and fowl were living with humans virtually the same manner, appearing extremely and, in ancient Egypt, the cat had made an frightened of humans and quite dangerous to appearance. Surprisingly, all currently domesticated handle. However, due to individual variation, there animal species were permanent fixtures within were some foxes that were slightly less afraid of human societies by about 3,500 years ago. This is humans than others. In each generation, Belyaev an amazing bit of trivia and it raises two important selected those foxes that were least wary of humans questions: (and eventually friendliest towards humans) for breeding. He did not care what they looked like or Of all the thousands of species on the planet, how they acted otherwise -- all he cared about was why are only a handful of them friendliness. After about 30 generations, the friendly domesticated? foxes were very different in their behaviour than Why haven’t more species been domesticated were the ‘normal’ foxes. in recent years? Once humans knew how to keep records and control reproduction, why Here you can see a normal, non-friendly fox, and didn’t they domesticate zebras and lions and here you can see the result of selecting for frogs? Why stop with cows and pigs and fowl friendliness for many generations. Interestingly, the and cats? friendly foxes also look different than their original ancestors. Because they were no longer being The answer to these questions cannot be that Adaptation, as described above, is initiated by domestication was a bad idea. In fact, it has been genetic selection for characteristics associated with one of humanity’s most successful ideas yet. By domestication, and sustained over very long 2,000 years ago, farmers and livestock herders periods of captivity. dependent on domesticated animals had taken over the inhabited earth. Similarly, while many wild animals are now endangered, domesticated animals have been very successful in evolutionary terms. They have migrated to nearly all corners of the globe, and, in some ways, have been very well looked after by humans. So why aren’t more animal species living with us in the types of close relationships we have with domesticated species? To understand this, we need to reconsider the processes of natural and artificial selection. According to Price (2002), “Domestication is that process by which a population of animals becomes adapted to man and to the captive environment by some combination of genetic changes occurring over generations and environmentally induced dev- elopmental events recurring during each generation” (p.11). There are several important points to note about this definition. First, the definition refers to a population of animals rather than to individual animals or an entire species. Belyaev did not change the nature of all silver foxes, but only those who happened to live in the environment he controlled. Similarly, taming a wild kangaroo is not the same as domesticating it and it will not affect other kangaroos. This means it is The third important point to note about Price’s possible to have domesticated and non-domesticated (2002) definition of domestication is his claim that forms of the same species. genes and environment interact to produce domestication. Crucially, this means that some animals may start out better equipped to cope with domestication than others. This is really important. In her book called 'A Natural History of Domesticated Mammals' Juliet Clutton-Brock (1987) analyses the history of domestication. She begins by discussing an essay written by Francis Galton in 1865. Galton was a cousin of Charles Darwin who wrote a great deal about evolution. He claimed that there was no reason to believe that domestication occurred because some highly civilised person thought it would be a good idea, and no reason to think it resulted from careful experiments or a detailed analysis of species attributes. Instead, he thought that there were Second, domestication requires adaptation, not just probably many examples throughout history of captivity. This is important because some people humans and animals trying to live together in appear to think that keeping animals captive for different ways, and that it just happened that a few many generations will inevitably result in of these were successful enough to persist. The domesticated animals. This is not correct. following quote was written by Galton in 1865. It is by humans, changes in temperature and humidity, interesting that, even back then, people were infection and parasites. Of course, less plasticity is predicting the environmental crisis we now seem to required if the domesticated environment is very be in the middle of: similar to the natural one. Keeping pigs in a large open-range area is likely to require less adaptation “It would appear that every wild animal has had its than keeping them closely confined in modern chance of being domesticated, that those few which growing environments. fulfilled the above conditions were domesticated long ago, but that the large remainder, who fail Appropriate pre-existing behavioural traits are the sometimes in only one small particular, are destined third thing that is very important for domestication. to perpetual wildness so long as their race According to Price (2002), animals most suited for continues. As civilisation extends they are doomed domestication: to be gradually destroyed off the face of the earth as useless consumers of cultivated produce.” naturally live in large, gregarious groups - this prepares them for social interactions and they generally accept some kind of dominance hierarchy are not aggressive are not very sensitive to changes in the environment are sexually promiscuous rather than bonding for life, and typically have sexual behaviour based on male dominance and signalling by way of movements or posture, not female dominance and signals based on colour or other physical The contemporary writer Edward Price (2002) traits agrees with Galton’s claim that only some species are suited to domestication. He lists a number of produce young that are born in a well- what he describes as pre-adaptations for developed state and that can be easily domestication. These include the following: separated from their parents First, there needs to be some kind of requirement have a short flight distance from humans so for the animal within human society – what Price are easier to tame and control calls ‘a captive niche to be filled’. Price notes that have a small home range so do not become it is very rare for animals to be domesticated in unduly stressed by inactivity or captivity tropical environments, where food is readily available. Instead, domestication events occurred are generalist feeders rather than having when humans needed an easily-maintained and specialised dietary requirements that are transported source of food, or animals for difficult to maintain transport, clothing, protection, vermin eradication or religious reasons. This suggests that there may Finally, a really important characteristic is that the be some wild animal species who are perfectly animals should breed easily. Some animals, even suited for domestication, but who simply never when provided with what humans believe to be an found themselves in the right place at the right optimal environment, fail to reproduce. This limits time. human ability to manage them, much less domesticate them. This is particularly the case with Price’s second condition for domestication is that the fish and birds, many of whom will not reproduce animals’ behaviour should be fairly plastic. It seems without first migrating long distances to a specific self-evident that animals which are able to adapt environment that humans find difficult, if not easily to new environments are those most likely to impossible, to replicate. survive domestication. Domesticated species need to be fairly self-reliant from a young age, and they This (less than 10 minute) video shows a recap of the need to cope with diets and environments imposed above. If you want to know the answer to the question at the end of that video, watch this (less domestication. While locating genes for than 2 minute) one as well. One of the requirements domestication may be a way off, there does appear for domestication highlighted in the video explains to be at least one neurochemical which is involved. why lions and tigers cannot be domesticated: Dopamine is a very important chemical in the brain because they are large carnivores. However, wolves and is implicated in all kinds of processes in also fall into this category. What do you think made humans, including movement, memory, motivation wolves different from lions and tigers, and therefore and reward-seeking, cognitive abilities, immune able to be domesticated? system function, heart function, and kidney function. In humans, having too little dopamine can cause neurological disorders like Attention Deficit Hyperactivity Disorder, Parkinson’s disease, and social anxiety. However, having too much is associated with mental illnesses such as schizophrenia and psychosis. Dopamine is released in humans and animals when they obtain something they really want. It causes that pleasurable feeling of accomplishment when you finally get that perfect slice of pizza, or even a date (or sex) with someone you’ve had your eye on for a while. Drugs like cocaine increase dopamine in the brain, which is what makes them so addictive. Domestic animals generally have lower levels of dopamine than their wild cousins. This is true of Belyaev’s foxes, certain species of shrimp, and rats. The reduced amounts of dopamine in the brain may encourage domesticated species to be less aggressive and generally more relaxed. Maybe we should call it the ‘domestication neurochemical’! What this means about the psychology of human-­‐ animal relationships The fact that some animals, and only some animals, Is there such a thing as a domestication gene? are pre-adapted for domestication has important One of the modern approaches taken by some implications for our understanding of human-animal scientists to understanding domestication has been relationships within society. First, it means that we to try to locate domestication genes. Remember cannot simply domesticate wild animals for the sake Belyaev’s foxes? When he started selecting for of species conservation. We might think that we can tameness, he noticed that he also produced a much ‘save’ endangered species by rearing them in larger range of colour variation than was normal. This captivity but, for some species, this strategy may suggested that the genes for tameness are co- never be successful. Second, when some people located very close to those for colour, or perhaps argue that we have no business keeping domesti- even that the same genes code for both colour and cated animals in captivity and should let them all go some behaviour. In other studies, the same pattern back into a natural environment, we might rightly has been shown to occur in some species of rats challenge what they mean by this ‘natural and mice, with black rats being much more easily environment’ and whether this would be a good handled than brown rats (Keeler & King, 1942). outcome for the animals. While it is true that Although most behaviours are controlled by humans get lots of benefits from having animals multiple genes, it seems that some genes have within our society, and that some of these animals major effects on brain chemistry. These can are very poorly treated, it is also true that, for some sometimes affect both colour and certain animals, domestication is now their natural state. behavioural characteristics, some of which may For many, this has also had advantages. In one contribute to a species’ adaptability and, thus, their sense, domestication has always been a two-way street. Humans might play a role in choosing are (or were) forced into the relationship. But is this animals we want to have around for some reason, really how it happened? How much choice do we but animals also ‘consent’ to being domesticated by actually have? And is it true that animals are staying alive and reproducing successfully. Why essentially passive (or resistant) in the process of would they do this? It is not that they make a domestication, with humans capturing them and then conscious decision to be domesticated, but there controlling all aspects of their lives until a are potential benefits for the animals involved. domesticated species is miraculously produced. These include access to shelter and protection from Some authors have argued fairly convincingly that predators, disease prevention and access to this assumption is not justified. veterinary medicine, improved nutrition and improved care of progeny. In a nutshell, while domestication has had some horrible consequences, some of which will be discussed in later topics, it has also improved living conditions for some species which are perfectly well adapted to living closely with humans. We need to keep this in mind when we think about human-animal relationships. While the concept of domesticated animals being perfectly well adapted to a captive environment can be difficult to grasp, if we use our own species as an example, things might become less confusing. Imagine your ‘natural’ state. Does it involve a cave, clothes made from animal skins, countless children, many dying at an early age, freezing weather, no electricity or running water, hunger, long walks to find food, and perhaps regular battles with neighbouring tribes? Or does your ‘natural state’ look more like your present life, with all its comforts? How do you think the average prehistoric human would cope with being confined to a small but comfortable home, with an office job in a small cubicle and long periods of inactivity? How would Of course, if scientists are able to identify and then they manage electronics like computers and manipulate ‘domestication’ genes, this could iPhones, and would they close their doors and potentially have an enormous impact on some windows to use air conditioning? Would they enjoy human-animal relationships. Imagine if it became the benefits of contraception, or find it unnatural possible to insert domestication genes from one and strange? How would they deal with modern species into a different one? Do you think we could diseases like cancer, heart disease, and old age? end up with domesticated polar bears or kangaroos? Might this be a way to save endangered species or, Hopefully, this example illustrates for you how in changing them genetically to suit a captive difficult it is to determine what is natural for a given environment, would we make them a different species. It is also difficult to know whether ‘natural’ species than they were initially? is always best. Some humans appear to be poorly adapted to our current ‘natural’ environment and In a later topic we will discuss how humans are unable to cope with the pressures of modern living. manipulating animals genetically for a range of Disorders like depression and anxiety affect millions different reasons. Some people are uncomfortable of people worldwide. In general, however, we are well with this and argue that humans should not interfere adapted to our ‘captive’ lives, and our welfare would with nature, but of course this is something we have suffer greatly were we to be displaced backwards by been doing since we first began domesticating several thousand years. Might some animals be animals by using selective breeding practices. It is similarly well adapted to the domestic environment hard to imagine that changing a few genes around they currently inhabit? A critical difference, perhaps, could have any more impact than what we have is that we choose to live how we do, whereas animals already accomplished with respect to wolves and modern dog breeds such as the Chihuahua and different ways. Only some of these were successful Xoloitzcuintli. Later in the subject we are going to in evolutionary terms, and these are the ones that meet super-sized salmon, featherless hens and exist today. fluorescent green rabbits – all manufactured using In previous topics we explored human evolution and modern genetic technologies. considered whether we developed our capacity to Summary think and to communicate at least partly because of our interactions with animals. The fact that we did In this topic we first reviewed different types of so – that our brains evolved to think and talk about biological relationships, classified according to other species as well as other humans – whether one or both of the species involved is undoubtedly led to us being pre-adapted for harmed or benefits from the relationship. We then domestication. When wolves first decided, perhaps considered how both humans and animals have of their own accord, to move into our camps, we changed over time, so that the relationships that may were able to imagine the benefits that this might once have characterised our forms of interaction may bring, and we were able to provide those resources no longer exist. Things have changed, and things will that the wolves required to stay with us. Later we continue to change; so, it makes sense for us to help presumably used similar skills to imagine them change in ways that suit us. This topic covered domesticating other animals, and we were able to how these changes take place, delving first into the identify and select animals that were pre-adapted for learning mechanisms that drive adaptation of living in close proximity to human camps. We individual animals. We also explored Darwin’s theory undoubtedly made many mistakes along the way of natural selection and the basic principles of but, over a very long period of time, this resulted in genetic science and the adaptation of species over the species alive today – a human species very well time. You should now understand the concepts of equipped to live closely with animals, and a variety individual variability and biological fitness, and how of animal species very well equipped to live closely both species and individuals can adapt over time to with humans. better suit their environment. You should also understand that there are limits to adaptation. It is simply not the case that individual animals can adapt to every possible environment and nor is it the case that all animals within a species are equally able to adapt. Nor is every species suitably equipped to be domesticated. This is important to anyone interested in the ways that animals live within our society because, although many people assume that domestication is something humans have done ‘to’ some animals, this is probably not an accurate description. It seems much more likely that domestication is a process that has happened simultaneously to both humans and other animals, because of natural selective pressures. During the millions of years of evolution that preceded the arrival of our generation on earth, humans and animals probably lived together in thousands of  Topic 4 References and/or supplementary resources: Clutton-Brock, J. (1999). A natural history of domesticated mammals. Cambridge University Press. Keeler, C. E. & King, H. D. (1942). Multiple effects of coat colour genes in the Norway rat, with special reference to temperament and domestication. Journal of Comparative Psychology, 34(2): 241-250. Kunzl, C., Kaiser, S., Meier, E., & Sachser, N. (2003). Is a wild mammal kept and reared in captivity still a wild animal? Hormones and Behavior, 43(1), 187-196. doi:10.1016/S0018-506X(02)00017-X Price, E. O. (2002). Animal domestication and behaviour. CABI Publishing. Shipman, P. (2012). The animal connection: A new perspective on what makes us human. W.W. Norton and Company. Tansley, A. G. (1935). The use and abuse of vegetational concepts and Terms. Forest Ecology and Management, 16(3), 284-307. Winfreem R. & Kremen, C. (2009). Are ecosystem services stabilized by differences among species? A test using crop pollination. Proceedings of the Royal Society B: Biological Sciences, 276, 229-237. doi:10.1098/rspb.2008.070