‘Asexual’ lizards and pioneer plants
Published: 3 December 2011 (GMT+10)
Lizard parthenogenesis is a built-in ‘fall-back’ enabling isolated females to propagate in the absence of males. New Scientist blunders on pioneer plants.
This week’s feedback deals with whether parthenogenetic lizards (where the females grow and develop embryos without fertilization from a male) were on the ark and whether we misconstrued the order plants are likely to colonize new habitats in. CMI’s Dr David Catchpoole replies.
T.W. from the Netherlands writes:
Dear member of CMI,
A few days ago, someone asked me a question which I cannot answer myself. The question was if parthenogenetic animals (like some “lesbian” land lizards), entered the ark of Noah. And if so, how can there be male and female of them when they only come in females?
Could you please tell me what the answer is of this question?
God Bless you,
CMI’s Dr David Catchpoole responded:
Thanks for your enquiry—to my knowledge, the first time we’ve ever been asked such a question!
Your question prompted me to read up on ‘lesbian lizards’. The Komodo dragon is one example of a lizard exhibiting such parthenogenetic reproduction. It’s worth noting that:
- Parthenogenetic reproduction mainly occurs in island lizard populations.
- It’s very rare that it is the only method of reproduction in those populations. (E.g. in the Komodo dragon population, it’s been estimated as accounting for no more than 75% of offspring.)
- When sufficient males are present, parthenogenetic reproduction is limited, i.e. normal sexual reproduction has primacy over the parthenogenetic option.
Considering the above points, it seems that parthenogenetic reproduction is a built-in ‘fall-back’ option enabling female lizards making landfall on isolated islands to propagate the species in the absence of any males. Once males make landfall, normal sexual reproduction resumes.
So your questioner can be answered using the above points. Point out to him that parthenogenetic reproduction was more likely to have come to the fore in the post-Flood world, as the land and air creatures dispersed from the Ark’s landing site. Though we cannot be adamant about the pre-Flood world, the context and language of Genesis 1 would appear to indicate a single land mass was likely. In which case, sexual reproduction would predominate, therefore all the various kinds of lizards and other creatures in which we see parthenogenetic capacity today would have had both male and female members. While taxonomists have a tendency to label an all-female lizard population on an island as being a separate species to other lizards, the biblical definition of ‘kind’ is much broader. So, the idea that Noah didn’t have male members of a lizard kind to take on board the Ark is plainly bizarre. Note, too, that a [single un-fertilised] female lizard can found an island population in the absence of any other lizard—no male or [other] female is required for parthenogenetic reproduction, notwithstanding the ‘lesbian lizard’ tag pinned on them.
I hope that helps.
T.W. wrote back to express his thanks for the answer:
Thank you very much for your answer. Yes, it is a very sufficient answer. I was almost afraid that there was a mistake in the book of Genesis, so thank you again.
Grahame G. from Australia writes in response to Surtsey still surprises.
An acquaintance of mine has questioned the statement in the seventh paragraph that “it was not the expected lichens and mosses which were the ‘early invaders’, but flowering plants” and how this doesn’t make sense biologically.
I now quote from this person: “Flowers have much more complex means of reproduction than lichens and mosses—they can cast seeds to the wind (Think Dandelions). This enables flowers and other more ‘advanced’ plants to send seeds miles away (sometimes around the world) for them to germinate on distant soils. Lichens and mosses can really only easily reproduce in their own vicinity. For those mosses and lichens to ‘Limp aboard’ so late in the game is not surprising in the least. They had to arrive, probably on floating debris from the mainland. It comes as no surprise that flowers would show up first. That article is also making a disastrous comparison—Surtsey is being colonized by existing organisms from a nearby land mass. New life forms are not spontaneously appearing. It is not a valid example of evolution, or abiogenesis, which is precisely why Creation.com seeks to promote it as ‘proof’ that evolution must be false.”
From what I can gather in your article it was the researchers who were surprised, not that CMI thought they were.
Perhaps this would be a good opportunity to directly address the fallacies in the argument and provide more detailed support of the statement made, or if it is the case, to correct/improve the statement/article.
“And biologists, too, have been surprised. ‘From the first, the speed, ingenuity and sheer unpredictability of nature’s colonisation of Surtsey wrong-footed them.’ For example, it was not the expected lichens and mosses which were the ‘early invaders’, but flowering plants.”
Dr David Catchpoole responds:
I agree with your friend’s comment that biologically there’s no reason to presume that lichens and mosses would precede flowering plants in the colonization of Surtsey. But it was the New Scientist article which pointedly referred to the surprising lack of any “evolutionary adaptation to the surroundings”. If it hadn’t been for the necessarily constrained word limits for Creation magazine articles, I (as author) would have been delighted to reproduce whole slabs of the New Scientist article, to make it clear to readers that it was New Scientist, not CMI, making the statements about scientists being surprised at the way Surtsey was recolonized. Here are two key extracts, from the Fred Pearce article in New Scientist, which do indeed make it clear that it was the scientists who were surprised, not that CMI thought they were:
“It was, some said, like the world being born afresh. It was like Mars, said NASA scientists, who saw a resemblance to the surface of the Red Planet. It is doomed, said others, predicting that the island would be eroded away within a few years. All have been confounded.”
“The scientists swiftly declared Surtsey a nature reserve to which they would control access. But from the first, the speed, ingenuity and sheer unpredictability of nature’s colonization of Surtsey wrong-footed them.
“Everyone guessed that the most visible early invaders would be lichens and mosses, brought by sea birds or blown on the winds from neighbouring Icelandic islands. No [sic] so. Instead it was flowering plants and grasses that took the lead. The sea rocket was no fluke. It settled in and was swiftly followed by lyme grass and sea sandwort, cotton grass and ferns. It was 1967 before mosses arrived, and lichens only limped aboard in 1970.
“A further mistake was to assume that all the colonizers would be local Icelandic species. Far from it. … Visiting geese and snow buntings, ravens and whooper swans bring seeds and insects from distant lands.
“Snow buntings brought the seeds of bog rosemary from Britain in their gizzards. And while Surtsey’s first slugs and earthworms were Icelandic, many of the insects came from mainland Europe. This was an ecosystem created, in the first days, largely by accident. There was no complex evolutionary adaptation to the surroundings nor even a replication of ecosystems on neighbouring islands. What came, came.”1
I think your friend should be congratulated on spotting the weak thinking in the New Scientist article. Similarly, he should be encouraged to apply the same discernment and analysis to evolutionary thinking in general. Maybe he could be persuaded to genuinely compare the evolutionary claims about what happened in the past with the biblical account of history with a view to seeing which best makes sense of the evidence surrounding us today.
Nigel M. from New Zealand asked if circumcision is a ritual implemented by God “to correct a design flaw”. Dr David Catchpoole responds:
No, it is not a ritual to correct a ‘design flaw’. But that is not to say that in a post-Fall sin-cursed world that circumcision does not have health benefits. Uncircumcised Allied soldiers serving in desert areas during World War I were much more prone to infections (i.e. underneath the foreskin) than their circumcised peers. That is eminently understandable under the conditions of being in a desert environment, under military privations, with a shortage of water for daily ablutions. But in more comfortable and hygienic conditions, with plenty of water for daily washing, being circumcised or not circumcised is of minimal, if any, health significance.
- Pearce, F., The fire-eater’s island, New Scientist 189(2536):48–49, 28 January 2006. Return to text.