Mark Ridley (zoologist)

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Not to be confused with another science writer with a similar name, Matt Ridley.
Mark Ridley
Born England
Nationality British (English)
Fields Zoology, Evolutionary biology
Institutions University of Oxford
Thesis The comparative economics of reproductive behaviour (1987)
Doctoral advisor Richard Dawkins

Mark Ridley (born 1956) is a British zoologist and writer on evolution.

He studied at both Oxford and Cambridge in the 1980s (his doctoral advisor being Richard Dawkins), was a professor at Emory University, Atlanta, U.S.A., and - as of 2005 - works at the Department of Zoology, Oxford University. Ridley has worked on the evolution of reproductive behaviour and written a number of popular accounts of evolutionary biology, including articles for the New York Times, The Sunday Times, Nature, New Scientist and The Times Literary Supplement. He claims to be honoured to be frequently confused for Matt Ridley, another writer on evolution who is also from the UK.[1]


Mark Ridley was born on September 8, 1956 in Bury St. Edmunds, Suffolk, England. He is the son of Rex and Ann Ridley. He was a former student of both Oxford University and Cambridge University in the 1980s where he studied zoology and biology. He obtained his B.A. in 1978 from Oxford University and his M.A and Ph. D in 1982 from Cambridge University. Mark Ridley emigrated to the United States in 1989. While in the United States he also was a professor at Emory University in Atlanta, Georgia from 1989-1995. Currently, he works at Oxford University in the Department of Zoology. His contributions to evolution are numerous. He has received the Gibbs Prize from Oxford University in 1978, was inducted into the British Society for Historic Science in 1980, and also received the Rolleston Memorial Prize in 1983. His achievements in the field of biology particularly evolution are shown clearly through his work and awards. Mark has published eight different works and continues his research (please refer to Table 1). Many other writers have written reviews about his contribution to evolution. Kenneth Korey reported, “in many places Ridley is a competent guide through complex material” (Gale Biography, 2002). "I think Ridley's book is one of the best texts available for students of evolutionary biology" reports Geoffrey C. Trussell of Northeastern University. It is evident that in the eyes of others Mark Ridley is appreciated for his assistance. Mark’s area of expertise is concentrating and interpreting evolution as well as Darwin’s primary texts, such as The Origin of Species and The Descent of Man.


How to Read Darwin (2006)

Evolution has always been a topic that is considered hard to understand. People have trouble examining and understanding it. It is a theory that takes some time for one to clearly grasp. However, over the years, Mark Ridley has used a question-and-answer approach to explain how Darwin carefully tackled problems by trying to show the reader how to understand specific arguments, “Mark Ridley uses a question-and-answer approach to explain how Darwin carefully tackled problems, and shows here how the reader can understand Darwin's arguments by first working out which question Darwin had implicitly set himself to answer” (Lehane, 2010). This is beneficial because his process helps the reader stimulate intellectual thought which helps facilitate the reading and obtain a better understanding. Critics report, “Mark Ridley’s thought process can be compared to the scientific method. He has a concise way to tackle a problem and delve into finding the solution” (Lehane, 2010). Therefore, one can assume that Ridley attempts at helping the evolutionary audience is simple and understandable. Ridley begins by explaining to his audience the question Darwin had once questioned himself. This is helpful because it gives the reader a clear outlook on the perspective of the reasoning of the person who did the original questioning. From there he portrays to the reader how to understand the question in order for it to be easier to interpret. William James coined the phrase “stream of consciousness” trying to explain internal monologue and the thinking process. Mark Ridley does just this in his book How to Read Darwin (2006). He tries to help the reader’s stream of conscious by giving them an easier approach on how to review Darwin’s theories. Mark Ridley takes it upon himself to be not only a student of Darwin but a teacher to all of Darwin’s supporters. This text is a detailed 119 pages of Ridley’s ideas on analyzing and discussing the different methods of understanding the various concepts of Darwin.

Evolution has always been a confusing topic; Ridley’s effort to help to want to help others is a contribution to evolution itself. Before one can clearly understand complexity it is essential to learn about the basics. This understanding is a big contribution on his part. Not only is he trying to further the theory of evolution but he is also trying to help others move at the same pace as himself and other evolutionists. He is essentially looking out for the good of all humans interested in evolution to help prevent confusion and to help further knowledge. Mark Ridley took a pause from his research and realized that this work is indeed hard to read and developed this text to aid people to help prevent the struggling that he went through when trying to analyze Charles Darwin’s literature.

Scientific Contribution[edit]

Natural Selection and genes

“The genetic variety produced by sexual reproduction offers many possibilities for how a population of organisms might change over time” (University of Wyoming, 2005). Natural selection is a key entity of deciding who the winning mate will be. Traits associated with reproduction evolve playing an essential role in reproductive isolation. Ridley speaks of the courtship methods of various animals, “Songbirds sing, frogs croak, fruit flies dance and throw up. The reason is probably what Darwin called female choice - females tend to breed with the males who sing, and who sing loudest and longest” (Ridley, 2000). Ridley makes a contribution to this topic by attempting to answer why females chose those mates who display odd behavior. He believes the answer to this question is due to an animal’s way to assess gene quality. Genes influence behavior, which in turn influence mate choice. Natural selection chooses genes that will benefit a species helping them survive and rejects those of no further use. Ridley explains alteration of gene activity also passes down from generation to generation. The common trend of females mating with males who show odd behavior is popular due to social interaction. Social interactions in animals also trigger changes in the nervous system that also alter gene activity. There are many pieces of behavior that are influenced by genes.
Studies have shown that mutations in genes occur when reproducing, “A human being makes 200 or so copying mistakes every time he or she breeds” (Ridley, 2000). The mutations are slowed down through the mating process. According to Ridley, an individual encounters two problems when attempting to assess the gene quality of another individual. “One is how to tell which suitors have good genes, and which have bad” (Ridley, 2000). Zoologist Peter Garson studied the European wren and discovered males who spend much of their time displaying and building nests are the most successful in being chosen by the female wren. “Data collected in one of two years suggested that individual females may show a preference for males with the largest number of complete but vacant nests” (Garson, 1980). The males that are successful in nest building are at top of the selection pool allowing their genes to move forward and be passed on. This is a proactive experience in which time and effort put into nest building will give the female wren confidence in the male, which ultimately makes courtship and reproduction possible. In addition, this also eliminates mutations from occurring slowing down the gene evolving process. More so for humans then animals, Ridley says “the second problem is that, during courtship, you are accompanied by the equivalent of a smooth-talking salesperson” (Ridley, 2000). A courting male may not portray his defects to the female because his primary interest is to use his better attributes to win the challenge at hand. A reference can be made back to the odd behavior that males show. Ridley’s reasoning of odd behavior proves that it does help distinguish males from the group making them stick out to the females.

Ridley shows that courtship has been shaped during evolution by allowing a fast assessment of gene quality in a way that is not open to wrong. His study that was directed towards animals can also be considered for humans. A healthier male is more likely to win over a female than a sick over weight male. Again courtship will solidify the gene process by the decision the female makes. If she chooses the healthier more fit male then their offspring’s will most likely be healthy as well. However, if she chooses the obese male their offspring can ultimately get or become carriers of the diseases that obesity may pass on. The gene selection process will evolve more towards a negative way than a positive one for the offspring. Therefore, which mate will the female chose? She will most likely be more impressed with and want to pursue the healthier male.


Ridley stresses the topic of fecundity. This is a topic that most evolutionist do not talk much about. However, Ridley does a great job in introducing and developing the importance of this topic through his text and studies. According to the online medical dictionary fecundity is defined as, “the ability to have children, usually lots of them with ease” (MedicineNet, 1996). Fecundity is also when females produce more offspring than can survive. This concept is indeed universal in nature; in every species more eggs are produced than can survive on to the adult years. Darwin specifically studied the fecundity of elephants. In Darwin’s words, “The elephant is reckoned the slowest breeder of all known animals” [Ricklefs and Miller, (2000]. further research on the fecundity of elephants shows that over a female elephants main breeding life span, the females produce exactly one calf every four years. “This is a fecundity rate of 0.25 including calves of both sexes” (Patterson, 1988). This is a slow reproduction rate in elephants. Elephants are considered endangered species. The fewer of them that there are the harder it will be for them to mate and carry on their breed.

Mark Ridley influences the thinking of his audience by showing an approach other than what Darwin described. Darwin proved his point of low reproductive rate using the elephant as a prime example and conversely, Mark Ridley explains high reproductive rates through the Atlantic Cod. Mark Ridley explains fecundity using the Atlantic Cod, “The fecundity of females increases with size and age. A 40 inch female may lay about 3 million eggs, and a 50 inch female up to 9 million eggs in one spawning season” (Dave, 2010). Furthermore, not looking at size but at age “An average 10-year-old female cod lays about 2 million eggs in a breeding season, and large individuals may lay over 5 million” (Ridley, 2003). Out of the 2 million eggs only two survive. The two eggs that survive on average are the ones that will successfully continue to exist living. These are the eggs that will one day reproduce to continue the cycle of life. This is important in understanding evolution because the eggs that do evolve into fish and continue living are successful in reproduction. Fecundity varies depending on which animal is being considered. As seen above, it can be either a high reproductive rate or a low one. Fecundity is closely related to fitness. Fitness is a term describing the measure of reproductive success, “In evolutionary theory, fitness is a technical term, meaning the average number of offspring left by an individual relative to the number of offspring left by an average member of the population” (Ridley, 2003). “Those individuals who leave the largest number of mature offspring are the fittest” (Kimball, 2010). The production of a large number of offspring is a measure of fitness. Fitness for the Atlantic cod is measured by the number of fertilized eggs they produce because they provide little to no care for their young. Both Darwin and Ridley stress the condition of fecundity perceiving it from different perspectives. All in all, Ridley along with other evolutionists believe organisms produce more offspring than the given limited amount of resources will allow to ever survive.

HIV affected by Evolution

Another point that Mark Ridley stresses is the evolution of drug resistance in HIV. “The increase in the frequency of drug-resistant HIV is almost certainly driven by natural selection” (Ridley, 2003). Reproduction, heredity, variation in individuals among the members of a population, and variation in the fitness of organisms are all characteristics that HIV possesses. A virus like HIV is prone to better and faster reproduction because it will develop the ability to resist drugs. Therefore, Ridley makes a point to prove that the HIV population when put in this type of situation evolves. Natural selection can cause adaptation or also cause a population to remain constant. Some features of HIV allow it to easily facilitate widespread resistance also due to its high mutation rate.
Another study was conducted, comparing “the rate of emergence of thymidine analogue mutations (TAMs) and major protease inhibitor mutations in adherent patients who remained on stable treatment with a thymidine analogue and/or protease inhibitor after the onset of virologic failure” (Goetz, 2006). This study proved that it was necessary to alternate the treatment plan in order to make it effective once again, “In patients kept on the same virologically regimen for a median of 6 months, there was considerable accumulation of drug resistance mutations” (Cozzi, 2007). The HIV became unaffected by a certain type of drug that was being used because it adapted to the environment it was being placed in. The virus evolved and as a result did not respond to the medicine whose purpose was to destroy the virus. Efforts are being made to find an alternative that will be more efficient; “The World Health Organization advocates a public-health approach rather than an individual-based approach to HIV treatment in order to make treatment more uniform and more available to all patients throughout the world” (Gilks, 2009). Both Ridley’s example and Goetz’s example prove that virus’s have the capability to evolve when they are exposed to the same drug over a period of time.
Mark Ridley’s example of the HIV virus portrays an example of adaptation. Ridley uses his knowledge to contribute to evolution by portraying how viruses can adapt and mutate. His study on HIV ties in perfectly will natural selection and evolution. Nearly all drugs currently used to treat this disease stop working after a period of usage and as a result cause AIDS.


In conclusion, Mark Ridley has been a powerful contributor to the topic of evolution. Ridley has made both literary and scientific contributions. He has written books such as How to Read Darwin (2006) to help his audience understand how to interpret topics revolving around evolution. Fecundity is a topic that is considered but not delved into. Mark Ridley through his text portrays to the reader the importance of fecundity and how impacting it is in obtaining a greater understanding of evolution. He uses his knowledge to explain natural selection in both a human and animal perspective. He has also done work in finding the “evolution” in viruses such as HIV. Further readings on Mark Ridley can be done. Currently, he is working at Oxford University where he continues to be a zoologist and further examine evolution.

Published works[edit]


  1. ^ Dawkins, Richard (2008). The Oxford book of modern science writing. Oxford University Press. p. 59. ISBN 978-0-19-921680-2. OCLC 180014200.