Monday, 28 September 2015

Evolution is a lie? Try telling that to the thousands of scientists who use it every day

One of the main reasons I accept the fact of evolution is that in my professional life as a doctor, the evidence for it is overwhelming. Comparative genomics declares the truth of human-ape common ancestry. Population genetics confirms that it is impossible for the entire human race to descend exclusively from two people living 6000 years ago. The human genome, far from being an elegant model of design precision is a sub-optimal structure that causes disease and which bears the hallmarks of its evolutionary origin. Furthermore, evolutionary principles are of increasing utility to medicine, from casting light on the frankly bizarre and sub-optimal nature of human anatomy and developmental biology to the emerging science of evolutionary medicine. I can no more deny the fact of evolution than I can deny the atomic structure of matter or any other uncontroversial fact of nature.

It's not just medicine in which evolutionary principles are of considerable utility. Agriculture is another area in which recognising the fact of evolution pays considerable real-world dividends, as Andrew Hendry et al pointed out in a 2011 review article in the journal Evolutionary Applications:
Evolutionary principles are now routinely incorporated into medicine and agriculture. Examples include the design of treatments that slow the evolution of resistance by weeds, pests, and pathogens, and the design of breeding programs that maximize crop yield or quality. Evolutionary principles are also increasingly incorporated into conservation biology, natural resource management, and environmental science. Examples include the protection of small and isolated populations from inbreeding depression, the identification of key traits involved in adaptation to climate change, the design of harvesting regimes that minimize unwanted life-history evolution, and the setting of conservation priorities based on populations, species, or communities that harbor the greatest evolutionary diversity and potential. The adoption of evolutionary principles has proceeded somewhat independently in these different fields, even though the underlying fundamental concepts are the same. We explore these fundamental concepts under four main themes: variation, selection, connectivity, and eco-evolutionary dynamics. Within each theme, we present several key evolutionary principles and illustrate their use in addressing applied problems. We hope that the resulting primer of evolutionary concepts and their practical utility helps to advance a unified multidisciplinary field of applied evolutionary biology.
That of course puts the evolution denialists in our community - particularly those who are laypeople with zero professional qualifications in evolutionary biology who do not understand the subject well enough to comment on it, let alone offer an authoritative opinion on it - in the curious position of making outlandish claims about evolution being 'science falsely so-called' which are flatly refuted by the fact that this 'science so-called' has real-world, tangible applications. Ours is an age in which the ability to critically evaluate claims made in lectures is as simple as checking mainstream scientific sites via smart phones and other devices, a fact which should remind evolution denialists in our community to exercise caution and intelligence before making claims that can readily be debunked. Credibility once lost is never regained, even if frantic attempts to substitute intimidation and misrepresentation for factuality are employed.

As the article is freely available online and is accessible to the educated layperson, there is no point in a detailed review when the authors have already done a splendid job. However, the take-home summary is worth reprinting if only to show that this 'science falsely so-called' actually has the runs on the board when it comes to actually being of practical benefit to medicine and the life sciences
  1. Understanding phenotypes (as opposed to just genotypes) is important because phenotypes interact with the environment, come under direct selection, and have ecological effects.
  2. Individual and population mean fitness can improve more rapidly through plasticity than through genetic change – at least in the short term. Genetic change, however, will often be necessary to finish any recovery.
  3. In the study of adaptation, the examination of specific genes is often insufficient. Adaptation will usually involve many genes, which highlights the importance of a quantitative genetic approach.
  4. Standing genetic variation in fitness-related traits is nearly ubiquitous, and so is likely to be the initial fuel for evolutionary change in response to environmental change.
  5. New mutations become important when standing genetic variation is absent or depleted. New mutations will be particularly important for organisms with short generation times and large population sizes (e.g., viruses, bacteria, and some insects and plants).
  6. Small population sizes, and especially bottlenecks, can lead to genetic problems. These problems will apply more often to current fitness (e.g., inbreeding depression) than to future evolutionary potential.
  7. Current trait distributions are a product of past selection. Evolutionary history can therefore help to understand the current state of affairs and to predict responses to future environmental change.
  8. Some evolutionary change is not possible because of limited genetic variation, trade-offs, or physiological constraints. Identifying these limits is difficult but can aid attempts to slow unwanted evolution.
  9. The phenotypes of organisms are an integrated complex of traits in association with each other. These associations influence the rate and trajectory of evolution.
  10. Natural selection generally favors traits that improve individual-level fitness, whereas humans often care about population-level traits, such as productivity or yield. Cognizance of these different levels of selection can be used to tailor evolutionary trajectories as desired.
  11. Phenotypic differences among populations or through time are usually adaptive, rather than the product of genetic drift. Exceptions do exist, particularly for very small populations or for traits under relaxed selection.
  12. Human activities impose particularly strong selection. Adaptive phenotypic change will be the result, and at least some of this change will be genetically based.
  13. Selection can be manipulated to help or harm organisms, but the resulting contemporary evolution can hamper these goals. Manipulating the dimensionality or timing of selection can have desired demographic effects while reducing undesired evolutionary effects.
  14. Allelic interactions alter natural selection in important ways. For example, recessive alleles are often sheltered from selection, which can be exploited to slow the evolution of resistance.
  15. Manipulations of connectivity that alter gene flow are an important management tool. Gene flow can be increased to reduce inbreeding or increase evolutionary potential. Gene flow can be decreased to reduce impacts of cultured organisms on wild populations.
  16. Adaptive evolution influences population dynamics and sometimes allows evolutionary rescue. Such effects are not inevitably large, and so an important topic becomes the conditions under which they will be important.
  17. Adaptive evolution will alter how organisms interact with their environment and can therefore influence community structure and ecosystem function. These effects are particularly pronounced for organisms that have large ecological effects (e.g., keystone species, foundation species) or that are very numerous (e.g., pathogens, pests, and weeds).
Full article is here: