Although the history of evolutionary biology dates back to 1858, it was not until the 1970s and 1980s that a notable number of universities included it in their departmental working titles. Concerned with the descent and modification of species over time, evolutionary biology, despite its gradual development, is now widely regarded as an important branch of science. Speaking with Editor Jonathan Miles, President of the European Society for Evolutionary Biology Professor Brian Charlesworth sheds light on the development of this interdisciplinary field.
What is evolutionary biology?
Evolutionary biology is mainly concerned with the 'why' question of biology, as opposed to the 'how' question, which asks how proteins operate inside cells, and how cells communicate with each other during development to create the mechanisms of the biological machinery. Evolution, in contrast, provides an answer to the question: 'Is what we see in the modern world of living organisms the product of a long historical process that has shaped the machinery that underlies their working?'
Evolutionary biology is a diverse area as it concerns everything in biology including, for example, the history of life as revealed by the fossil record. You can also look at the functioning of the components of the whole organism, and try to interpret them in terms of the idea of adaptation and natural selection, where weeding out less efficient variants has produced machinery that works rather well. Evolutionary biology also looks within populations to try to understand the relationships between the characteristics of an organism and its biological fitness; the effect of a particular trait on the survival or the reproductive success of an organism.
What role does DNA play in evolutionary biology?
You can study the history of life by comparing living organisms among themselves and trying to reconstruct their evolutionary history – for example, from the similarities in their DNA sequences.
We currently get enormous amounts of data from DNA sequences, which means that we can examine evolution in considerable detail at the level of the DNA itself, as well as regarding the organisation of the DNA and the genome. Modern technology provides us with vast amounts of information, so this field covers virtually the whole range of biological phenomena.
However, looking at it from the perspective of 'how we can make sense of this' – in terms of what we understand about the basic mechanisms of evolutionary change – there's a strong theoretical structure that is unusual for biology. As a result of this, people make mathematical and computer models based on their understanding of what we think is going on, and try to relate this to what we actually see in the organisms. This has had a long history that goes back to the beginning of the 20th Century.
When genetics was first discovered, the rules were used to try to infer what is expected to be seen when the basic evolutionary processes of mutation and natural selection were put into models, and then relate them to the data you can get from populations. This is very successful at the moment, because of the explosion of data coming from DNA sequencing studies.
What are the research priorities in the field?
A priority area in Europe with public policy implications is the evolutionary biology of an infectious disease. This can be studied by using the sequences of the genomes of these organisms, employing clever techniques to model how rapidly these diseases are changing, and then trying to pin down what is causing disease outbreaks, such as the recent swine flu epidemic.
Another big area is evolutionary genomics, which uses modern technology to generate large amounts of data on the DNA sequence of almost any organism, so that related species can be compared and their evolutionary history can be worked out. Perhaps more importantly, the entire genomes of different individuals from a population can be sequenced, and consequently the variability between individuals can be examined. A great deal of emphasis has been placed on trying to identify variants related to various kinds of disease, and a lot of work has been done on this in humans. Genomic data can also be used to answer 'tree of life' questions, which try to look back to the beginnings of life and relate the major groups of organisms together.
There is also a lot of interest in 'evo-devo' – trying to relate the process of development that we see to evolutionary questions, for example: 'How does a wing evolve in terms of the kinds of genes that are involved in controlling the development of the wing, and can you relate those processes to the selective forces that produced it?' Obviously, we know that wings are used for flying, but sometimes it's not so obvious why something is doing what it is doing.
Overall therefore, there is a great deal of interaction between basic information that comes from molecular and cell biology, and the kinds of questions that evolutionary biologists have traditionally been studying.
What areas of evolutionary biology are mainly researched in the UK and Europe?
There's a strong emphasis in the UK and Scandinavia on behaviour ecology, which is the study of animal behaviour in their natural environment, and trying to interpret what animals do in relation to what kind of natural selection has been acting on them to make them do what they do. What is perhaps not so strong in Europe is the more genomic and molecular approach to evolution, which is better represented in North America.
Probably the weakest area of research in Europe is the study of evolution in the plant kingdom, which is important since we eat plants. This used to be quite strong in the UK, but whilst there is currently a lot of molecular biology done on plants, there is very little evolutionary biology, and that's probably true in France and Germany as well. People should perhaps be thinking about trying to encourage research into this area a bit more.
Why does evolution matter in society?
The intellectual importance of evolution and its interest for the general public cannot be overestimated. What evolution is telling us is that organisms – including humans – are the product of around 3.5 billion years of history, and we have a pretty good idea of what is driving it. This basically involves the kinds of ideas that Darwin proposed 150 years ago – modern evolutionary biology has confirmed a lot of Darwin's ideas, especially natural selection being the cause of adaptation.
We now have strong insights into how this is working: the bottom line is that we humans are nothing special; we're just one twig of a tree produced by a long history. This is important as it means that we're all part of the living world, with implications for the conservation of the natural environment – we should be aware that we have intricate relations to animals, plants and microbes.
What is the practical importance of this area of study?
Microbes can do a lot of evolving very quickly, and can consequently do a lot of damage if we stir things up too much, so disease and evolution are clearly of practical importance. Also, it's probably little known that many of the methods that have been traditionally used in animals and plant breeding to improve them from a human point of view are based on ideas and methods from evolutionary biology. In order to go forward, even with genetic manipulation based on modern technology, we have to have an understanding of the consequences of messing around with the genomes of creatures, and that involves input from evolutionary biology.
Do you see evolutionary biology as a growing research field in the UK?
There is a good deal of practical importance to what we do, and there is a need to fund both the applied aspects of the field and the basic research that underpins this, so I would like public policymakers to be made aware of that. The field is relatively small compared with the rest of biology (possibly around 10% of the funding goes to evolutionary biology and about 90% for molecular and cell biology), and consequently the community feels itself to be a little bit of a minority that is more than somewhat outnumbered by the people studying the mechanistic areas of biology (the 'how' questions, rather than the 'why' questions). However, I think we have something very important to offer.