This article is from
Creation 17(1):22–23, December 1994

Browse our latest digital issue Subscribe

The guppies and the nematode...
Selling evolution to the masses

by Jerry Bergman


A good example of how evolutionists try to argue their case to the public was found in an article by Shannon Brownlee, 'Sex, Predators and the Theory of Evolution', in a U.S. News and World Report.1 The article quoted two intriguing studies which showed the enormous adaptability of animals.

According to the report's author, the researchers in one study moved 200 guppies from the base of a 6-metre (20-foot) waterfall in the Aripo River to the waterfall top.

At the waterfall base, predatory fish known as cichlids prey only on adult guppies, and at the top of the waterfall the only predator is the killifish which devours only younger guppies. This was the major difference in the environment, and the one on which the researchers focused.

After 60 generations, the guppies in the new location at the waterfall top reached sexual maturity nine days earlier than their downstream cousins. They were also larger when they gave birth and had fewer offspring.

Together, these responses facilitated survival in their new location and can be explained by natural selection: the larger guppies and those that matured earlier were less likely to be killed by the killifish, thus selecting for earlier maturity and larger size.


A second study showed that certain nematode (roundworm) parasites were found to cause the male jungle fowl to have dull eyes and combs, making it less attractive to females.

Although the nematode lives in the animal's gut, it changes the outward appearance of its host so that it is less likely to mate. The females prefer males that do not have the traits that the parasite causes, thus (not surprisingly) those males with resistance to the parasite will have more offspring.

From these studies, the report makes the amazing statement:

'Taken together, studies such as Resnick's and Zuk's strike a resounding blow to all who would doubt the veracity of evolution. It has taken more than a century, but Darwin's theory is finally being put to the test, and it is coming through with flying colors ... until very recently, Darwin's ideas remained unproved. Now, for the first time, studies in the wild are rigorously demonstrating the particulars of how evolution works.'

It is interesting that evolution, which many evolutionists have been insisting is fact for generations, was unproved until recently, according to this report. But the proof offered is hardly convincing (nor does it appear that the researchers themselves said this).2



Such claims vividly reveal the bankruptcy of naturalistic evolution theory today; when examined closely, this research does not help evolutionists at all. As Brian Charlesworth noted in the journal Nature, referring to David N. Resnick's work with the guppies:

'Such studies merely show that genetic variability of the kind postulated in the models can be exploited by selection: they do not prove that the invoked selective agents are actually responsible for producing the observed differences.'3

In the case of the parasite, those jungle fowl already possessing the genetic information which made them more resistant were more likely to pass on this information to their offspring. How is this fundamentally different from the well-known observation that mosquitoes already resistant to DDT are more likely to survive to pass this 'resistance information' on to their offspring? In both cases, the evidence fits directly into a creation model, with selection operating to cull and thin out (not increase) the (created) information already present.

There are thousands of examples of animals and plants which, when they are placed in a new environment, adapt in an amazing variety of similar ways. This is only one illustration of the large inborn repertoire of responses to environmental pressures that many animals possess.4

Creationists fully recognize this means of facilitating adaptation, but are willing to go only as far as the evidence leads them. Conversely, evolutionists extrapolate these examples far from what the data show, hypothesizing that natural selection evolved bacteria to men. They do this even though such examples do not demonstrate how the new information required for such a transformation arose.5

It is reasonable to suppose that, if the guppies were returned to the base of the waterfall they would revert back to their original form.



Tom McIver, in a summary of a work by the eminent biologist, Professor D'Arcy Wentworth Thompson, said that Thompson had argued in 1917 already that natural selection 'only eliminates the unfit and is not progressive', and therefore cannot create.6

Thompson showed that the genetic make-up of an organism was designed to produce much variety in the animal type in order to aid adaptation. He called this process 'direct adaptations' and, in contrast to evolutionary theory, it occurs after only a few generations 'in response to immediate physical, environmental forces, rather than by the accumulation of hereditary adaptations.'7

Today we know of the work by Barbara McClintock on gene units called transposons. These 'jumping genes' can move from one location on the genome to another to turn genes on and off, naturally producing variety by complex genetic mechanisms. This is only one of several means, such as sexual recombination, that produce variety from existing (created) information in an organized way, facilitating adaptation.

New 'proofs' such as the guppies and the nematode are regularly voiced by evolutionists and just as regularly forgotten. The tragedy is, the general public is told that these discoveries 'prove' evolution, without being given the opportunity to find out that the true explanation supports creation and gives absolutely no comfort to those looking for an explanation as to how molecules evolved into man.


  1. Shannon Brownlee, 'Sex, Predators and the Theory of Evolution', U.S. News and World Report, August 13, 1990, p. 60.

  2. David N. Resnick, 'Genetic determination of offspring size in the guppy (Poecilia reticulata)', The American Naturalist, August 1982, Vol. 120, No.2, pp. 181-188; David N. Resnick et al, 'Experimentally induced life-history evolution in a natural population', Nature, Vol. 346, July 26, 1990, pp. 357-359; David N. Resnick, 'Plasticity in age and size at maturity in male guppies (Poecilia reticulata): An experimental evaluation of alternative models of development', Journal of Evolutionary Biology, Vol. 3, 1990, pp. 185-203.

  3. Brian Charlesworth, 'Life and Times of the Guppy', Nature, Vol. 346, July 26, 1992, p. 313.

  4. David N. Resnick, Heather Bryga, and John A. Endler, 'Experimentally induced life-history evolution in a natural population', Nature, Vol. 346, July 1990, pp. 357-359.

  5. Evolutionary theory of course claims that mutations (inherited copying mistakes) are the source of the raw material. But this is another question altogether — whether observed mutations demonstrate the supply of adequate 'uphill' information. Survival benefit is not enough — a loss/defect may give such a benefit (wingless beetles on windy islands are less likely to be blown away and drowned).

  6. Tom McIver, Anti-evolution; An Annotated Bibliography, McFarland and Company, Inc., Jefferson (NC), 1988, p. 272.

  7. ibid, p. 273.