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All this week we're celebrating Darwin and the advances in evolutionary theory that have built upon his work.

Darwin famously delayed his masterwork, On the Origin of Species, over concerns about how it would be received.

He was right to be worried. The implications of his theory of evolution by natural selection undermined established beliefs about humanity's special place in the world and turned man into just another animal - with apes for cousins and worms for ancestors.

It provoked hostility at the time and has been used since to justify everything from colonialism and class warfare to the holocaust. So how should we think about human evolution now?

'These negative associations are not really valid as evolution is not a political vehicle facilitating forms of cultural over-lordship but rather an unconscious force applicable to the entirety of our species,' Oxford's Timothy Clack, who studies archaeology and biological anthropology, told me. ' We are all Homo sapiens and all share the same evolutionary history.'

Driven to destruction?
Timothy believes that our evolutionary drives are at odds with our modern way of life and this conflict is having a dire effect on our physical and mental health, as well as the environment:

'Rates of diabetes, obesity, heart disease and high blood pressure soar because our bodies are unfit for purpose in environments where we consume vast amounts of fat and carbohydrate and levels of physical activity are in decline. We have insatiable appetites for high-calorie foods because in the evolutionary past they were rare and on those infrequent occasions when they were encountered, for example on finding a honey-rich beehive or a clutch of bird eggs, it made sense to gorge oneself. Unfortunately there is no off-switch and the availability and low-cost of these food items nowadays results in their over-consumption.'

The other problem is that we no longer behave like the hunter gatherers we evolved to be and burn off any excess calories: stamina and an athletic frame are hardly necessary to hunt down food in your local supermarket. 

It's not just physical, according to Timothy humans also miss out on the rich and long-lasting social bonds fostered in tight-knit hunting bands of up to 100 members. He comments: 'Real friendships are in shorter supply than ever before because our geographic mobility, frequent relocations, endless commitments and levels of exhaustion deny us the time necessary to develop them. '

Under the influence
Yet despite this mismatch our inherited evolutionary drives remain very powerful and are used by everyone from advertisers to politicians to influence us.

Timothy explains: 'Models are used to promote things because we respond positively to attractive people. By playing on our evolutionary disposition good advertising helps us accept that any particular product is sexier, newer and better than the competition. We learn that status is enhanced with possession. At the same time consumerism is linked to our compulsion for territorial marking and resource acquisition; both of which are important for attracting mates.'

'Both the sexes have voyeuristic predispositions and these evolved on the savannah at a time when sex was a public enterprise. We may have placed intercourse modestly behind the bedroom door but flirting and other performances of attraction still take place in the open. Sex appeal has taken on greater significance in the modern media culture where the image has replaced the word as the primary means of communication. Politicians are getting younger and more attractive because these qualities correlate with sex appeal. We generally afford the good-looking more trust and confidence.'

Going against Nature
So is the battle against our evolved instincts hopeless?

'The good news is that not all of our evolutionary heritage is harmful. Certain qualities like innovation, emotion, empathy, sociality and language can be embraced. The bad news is that the more negative traits will be difficult if not impossible to shake. There is a little room for optimism, however, for in recognising negative traits we can strive to mitigate their impact.'

'Natural selection may have been the human architect but thanks to the many adaptations it implanted we find ourselves in pretty exceptional territory. Our self-awareness and ability to comprehend the evolution and future of our species uniquely places us to resist impulses and drives. Culture bestows on us the means to refrain from antisocial behaviours, even those that may have some fashion of evolutionary basis. In certain locations over the course of three generations we have seen major steps in the fight against racial segregation, sexual inequality and religious persecution. Therefore we must not deploy evolution as an excuse for in doing so we legitimise the worst of our character.'

Dr Timothy Clack is the author of Ancestral Roots a book exploring the links between modern day problems and our evolutionary past.

Read more of our Darwin special: worms & vertebrates

All this week we're celebrating Darwin and the advances in evolutionary theory that have built upon his work.

I asked Peter Holland of Oxford's Department of Zoology about early vertebrates, worms and us:

OxSciBlog: How has genomic science changed how we think about evolution?
Peter Holland: Genomics hasn’t changed the way we think about evolution at a fundamental level – I mean, even before genomics we knew that evolution is a fact consistent with all biological knowledge, that all life on earth diversified from one origin, and that the dominant forces underpinning evolution are mutation and selection. But what genomics has done is added colour and detail to that picture.

For example, sequencing of genomes has given us new insights into the different types of mutation, not only small changes to individual genes, but big mutations that copy whole sets of neighbouring genes in tandem, or duplicate entire genomes.

And we should not forget the technological advances that genomics has driven, such as faster, cheaper DNA sequencing. This now enables researchers to deduce the past history of life on earth using hundreds of genes at a time, not just one or two, with some major new insights into the true tree of life.

OSB: How far back can we trace the basic body plan of vertebrates?
PH: All vertebrates share the same fundamental body plan, with a complex head built from moving ‘neural crest’ cells, a subdivided brain, segmented blocks of muscle and a skeleton of some sort. Only vertebrates have all these features together, and even the oldest vertebrate fossils show signs of them.

Interestingly, when we look at our closest non-vertebrate relatives (amphioxus and sea squirts) we find some of these features in rudimentary form, implying that the extinct vertebrate ancestors also had these rudimentary structures.

So when the first vertebrates evolved, perhaps 550 million years ago, evolution just elaborated on what was already present, by adding some new cell types such as bone, cartilage and an adaptive immune system.

OSB: Why, in terms of evolution, are genome duplication events important?
PH: In 1882, the satirical magazine Punch published a cartoon about Darwin entitled ‘Man is but a worm’. We now know that actually ‘Man is but four worms’, because at the origin of vertebrates the whole genome – every gene – was duplicated twice. Many of the extra genes were lost after this event, but vertebrates still retain more genes than most invertebrates.

It is tempting to suggest that these extra genes were recruited for new roles, allowing new tissue and cell types to evolve, and in fact there is evidence to support this hypothesis.

However, this does not mean that genome duplications are always associated with adaptation – for example, the squid and octopus lineage evolved anatomical complexity without genome duplication, while teleost fish experienced a genome duplication without obvious increase in complexity.

OSB: What major questions about the evolution of early vertebrates remain to be answered?
PH: We don’t have a good handle on the timeframe – we need more fossils to give us better dates. We also don’t fully understand how new genes gain new roles, and this is notoriously difficult to study. And finally it has been difficult to work out how lampreys and hagfish fit into the history  – did they branch off before the two genome duplications, after, or in between? This last point has spawned many heated discussions!  

Peter Holland is Linacre Professor of Zoology and Associate Head of the Department of Zoology at Oxford.

To most people the idea that ants communicate using sound is pretty surprising.

So how much more surprising is that these ant sounds (in particular queen ant sounds) are mimicked by the pupae and caterpillars of an ant parasite: the Rebel's Large Blue butterfly?

As The Times, amongst others, reports this is exactly what a team including Oxford's Jeremy Thomas have demonstrated in research published in this week's Science.

The original idea came to Jeremy some 15 years ago when he was recording the stridulations of worker ants and caterpillars and noticed similarities between calls of certain species. He realised that these sound signals might explain his observation that sometimes worker ants treated the caterpillars like ants queens when the caterpillar's chemical and behavioural signals only mimicked those of ordinary ants.

However, it would be over a decade before audio equipment was sophisticated enough to prove whether or not the idea was correct. 

The team tested the theory by recording and then playing back the sounds made by queen ants to workers in a nest. Jeremy told Lewis Smith in The Times: 'When we played the queen sounds they did 'en garde' behaviour. They would stand motionless with their antennae held out and their jaws apart for hours - the moment anyone goes near they will attack.'

In short, the right sound signals cause workers to protect and care for an invading caterpillar as if it is their queen.

Such a discovery is especially important because the Rebel's Large Blue (Maculinea rebeli) is an endangered species, Jeremy notes: 'The new findings will play a key part in designing a successful science-led conservation strategy... Any such strategy must be based on an excellent understanding of the intimate interactions between the butterfly and its ant host.'

'There is also an urgent need to investigate whether acoustical mimicry has evolved among other, rare, social parasites that infiltrate and exploit ant societies.'

Professor Jeremy Thomas is Professor of Ecology at Oxford's Department of Zoology and a Professorial fellow of the Centre for Ecology & Hydrology

The work was carried out by researchers from Oxford University, the Centre for Ecology & Hydrology and scientists from the University of Turin, Italy.

This week the government announced a new five-year strategy to improve the quality of treatment of dementia in England.

Neil Hunt, chief executive of the Alzheimer's Society, was quoted on BBC Online as saying: ‘One million people will develop dementia in the next ten years. This is a momentous opportunity to avert a dementia crisis that could overwhelm the NHS and social care.’

Gordon Wilcock, Professor of Clinical Geratology in the Nuffield Department of Clinical Medicine at the University of Oxford, chaired one of the major working groups that contributed to the content of the strategy. Professor Wilcock is also Vice President of the Alzheimer’s Society, which ran the various working parties.

I asked him about the strategy and his own work as director of OPTIMA – the Oxford Project to Investigate Memory and Ageing.

OxSciBlog: Why do we need a national dementia strategy?
Gordon Wilcock: Dementia has languished behind many other illnesses in terms of a comprehensive strategy to ensure early diagnosis, treatment and support. It is estimated that there are at least 700,000 people in the UK with dementia, and in most cases the effect of their illness has a major impact on their family and those that care for and about them.

The consequences of dementia also make a major demand upon the resources of both the NHS and social service provision. Anything that can reduce this burden of illness will have major benefits not just for patients and their families, but also within the health and social service caring environments.

OSB: What are the challenges ahead in providing high-quality care for people with dementia and their families?
GW: One of the major challenges is the sheer number of people with the condition who need to be assessed and managed. An equally important challenge however is the need to educate people, both lay and professional people, about dementia and the need to do something positive about it. Providing resources for new services in the current economic climate is also going to be challenging. 

OSB: What outcomes will you be looking for as the strategy is implemented?
GW: I would expect to see a steady increase in the number of people assessed and appropriately diagnosed with dementia, and adequate support provided for them and their families. This is a five-year strategy and I would hope that at the end of this period, everyone with dementia will have access to a specialized clinic, to whom GPs can make referrals having themselves better understood the problems of dementia and how to initiate assessment. 

OSB: What are the priorities for OPTIMA?
GW: OPTIMA’s priorities include improving both diagnosis and treatment, and also to increase our understanding of risk factors that contribute to the development of the diseases that cause dementia. We would like to make it possible to diagnose people before they are significantly impaired and offer them new treatments, as these become available, to slow down the rate at which their brain cells fail.

OSB: What are the challenges for research?
GW: The biggest challenge at the moment is developing tests that will identify the disease processes that are going to cause dementia before they have actually done so. There are a lot of new treatments in development, and some in clinical trials, that may slow the disease such that the onset of dementia may be delayed significantly. Identifying people at this early stage is very important.

Dementia research is also exploring new approaches to treatment, based upon the underlying changes in the brain that affect brain cells. Coupled with this, however, is the need to develop tests that will show whether or not a potential new drug is really going to be helpful. This will probably involve more sophisticated use of brain imaging techniques, and also biochemical changes that can be measured in the blood and cerebrospinal fluid.   

You are starving, a prolonged drought means the nearest remaining food lies across miles of desert full of hungry predators ready to gobble you up: what do you do?

If you are a Desert locust you undergo a Jekyll & Hyde style transformation and turn from a shy, solitary individual into a gregarious, swarming migrant.

As reported in (among others) BBC Online, The Times and The Independent scientists including Oxford's Mike Anstey have finally identified the specific changes in the nervous system that affect this transformation: in particular the role of the brain chemical serotonin.

Previous research at Oxford had tracked down the physical stimuli that kick-off the change in lifestyle - a tickle of the locust's back leg was found to be the most powerful stimulus.

Part of Mike's work involved pinpointing the timeframe for the change in locust behaviour - something which happens before a stimulated insect changes body shape and colour. Once that was established the researchers could examine a range of chemicals in locusts to see which ones change as a result of the physical stimulation.

'Surprisingly, the only chemical that increased in the two to four hour timeframe it takes for the locusts to become gregarious was serotonin,' Mike told me. 'Although we had no idea that serotonin would play such a critical role in the process, it makes sense that serotonin is the culprit since it is well-known as a chemical found in the nervous system of other animals (including humans) which mediates behavioural changes towards others.'

In locusts an increase in serotonin causes them to be attracted rather than repelled by other locusts. Essentially the food shortage makes them 'switch' to the sort of safety-in-numbers strategy used by other animals in which a large pack of individuals moving as one confuses predators, enabling them to migrate in greater safety.

So why don't locusts live in swarms all the time?

'Although they are safer than predators they are at high risk of being cannibalised by other members of the swarm, which happens quite often!,' Mike explains. 'Switching to the gregarious phase is really the lesser of two evils - individuals will certainly die of starvation if they do not migrate and are only quite likely to die by migrating.'

The findings are evidence that serotonin is responsible for behavioural changes that occur as a result of interactions with others across a wide range of very different animals: from insects to humans.

Dr Mike Anstey completed the work whilst at Oxford's Department of Zoology.