Part 3 - Darwins Dilemma, Creationist Propaganda and Corrupt Christians

The previous post is available here.

Having ‘proved’ that fossils predating the Cambrian radiation are non-existent, and that all modern animal phyla appeared out of nowhere - in what the narrator describes as a “burst of creativity” - Darwin’s Dilemma the movie, then proceeds to ridicule Darwin the scientist. In their distorted reasoning, the creationist filmmakers think that if they can discredit a scientist that lived 150 years ago in Victorian England, somehow the audience will be convinced that the whole of modern science is erroneous. To initiate the strike against their biology bent Beelzebub, another carefully cropped quote is thrown to screen;

“Nothing distressed him more than the Cambrian explosion…” - Stephen J. Gould

For some unknown reason, creationists love Stephen Gould. Their infatuation may have something to do with a distorted view of Gould’s ‘punctuated equilibrium’ model; perhaps somehow the idea of a long stasis followed accelerated change translates to divine creation in the minds of simpletons? At any rate, Stephen Meyer or some other failed scientist from the Discovery Institute must have gotten this Gouldian morsel shorthand in a text message. They certainly didn’t get it from the page 238 of The Panda’s Thumb, the book in which Gould uses it to illustrate the lack of discrepancy between long past Darwinian predictions and modern paleontology.

It is certainly true that Darwin struggled with the lack of fossils predating the Cambrian radiation, speaking to intermediate fossils in Chapter 10 of the Origin of Species he wrote;

“Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against my theory.”

Of course, as with the Richard Dawkins quote yesterday and the Gould quote above, Darwin is here using the presupposition of a question as a lead to his explanation. And although the film in question is in the habitat of mining only the presumptive portions of these literary tools, the authors’ answers usually follow. In the case of Darwin’s true dilemma alluded to in the Origin of Species quote, he explains later in chapter 10 that,

“The explanation lies, as I believe, in the extreme imperfection of the geological record…. we continually overrate the perfection of the geological record, and falsely infer, because certain genera or families have not been found beneath a certain stage, that they did not exist before that stage. In all cases positive paleontological evidence may be implicitly trusted; negative evidence is worthless, as experience has so often shown…
Those who believe that the geological record is in any degree perfect, will undoubtedly at once reject my theory. For my part, following out Lyell's metaphor, I look at the geological record as a history of the world imperfectly kept and written in a changing dialect. Of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved, and of each page, only here and there a few lines. Each word of the slowly-changing language, more or less different in the successive chapters, may represent the forms of life, which are entombed in our consecutive formations, and which falsely appear to have been abruptly introduced. On this view the difficulties above discussed are greatly diminished or even disappear.”

Basically stated, what Darwin was implying was that, due to erosional processes, fossils are rare in the first place, and the oldest of all-the-fossils on Earth are rarer still. And he further predicts that despite these natural conditions, predecessor fossils are there and will be found as time proceeds and paleontological excavations are made. Darwin was right on-target with this prediction. In the 150 years since publication of the Origin of Species, numerous fossils have been unearthed, including those of the Ediacara biota, some from the Doushantuo formation and even the fascinating Markuelia fossil embryos – all predating the radiation vent! But, alas I guess these fine fossils don’t count… After all, as Paul Chien the head of the Discovery Institute’s paleontology section tells us in the film,

“to the paleontologist, the lack of intermediate fossils is well known.”

And Paul Chien should know, because he’s Chinese! As he later explains, “the Chinese community is honest about these problems and tries to explain them outside of Darwin.”

In addition to having an Asian heritage on his side, Paul Chien is a fellow of the Discovery Institute where he helps ‘spread the good word’ by translating Christian pseudo-science into the Chinese language. The worst part of Chien’s resume is that he’s also a biology professor at the University of San Francisco – tsk tsk San Fran.

Chien’s appearance marks a second transition point in the film’s diabolical plot. Leaving the fossils in the past, the modern sciences of evolutionary development and molecular genetics take center stage. In concert with this changeover is implementation of a new strategy – drawn the audience with science-ish jargon and convince them of life’s irreducible complexity. Leading this new front is Steven Meyer himself; holstered at his side is information theory. Brandishing this weapon he aims to shoot down “Neo-Darwinist storytelling” – by showing that modern genetics has nothing to do with evolution…


TO BE CONTINUED – AND CONCLUDED - IN PART 4



Condon, D. (2005). U-Pb Ages from the Neoproterozoic Doushantuo Formation, China Science, 308 (5718), 95-98 DOI: 10.1126/science.1107765


Dong, X., Donoghue, P., Cunningham, J., Liu, J., & Cheng, H. (2005). The anatomy, affinity, and phylogenetic significance of Markuelia Evolution Development, 7 (5), 468-482 DOI: 10.1111/j.1525-142X.2005.05050.x

Morris, SC (1995). Ecology in deep time Trends in Ecology & Evolution , 10 (7), 290-294

Part 2 - Darwins Dilemma, Creationist Propaganda and Corrupt Christians

Before picking up with the Richard Dawkins quote used to close yesterday’s post (Part 1 Available Here), I’d like to provide a little more background on some of the nefarious figures that contributed to bringing the fundamentalist film Darwin’s Dilemma to my living room.

The movie was produced by the Discovery Institute’s associate organization ‘Illustra Media.’ In this instance I use the phrase ‘associate organization’ very loosely because for all practical purposes Illustra Media is synonymous with the group known as ‘Discovery Media.’ Both media groups, Illustra and Discovery, receive the bulk of their funding from the Discovery Institute and both have Stephen Meyer as a lead consultant. Meyer is one of the Discovery Institutes original founders, and a key organizer of the intelligent design faction. For those readers unfamiliar with the Discovery Institute itself, I’d strongly encourage you to view Judgment Day: Intelligent Design on Trial, which details a 2004 federal court case in Dover, Pennsylvania. The NOVA documentary is provided free online by the Public Broadcast Service and very accurately summarizes the Discovery Institute’s deceitful and underhanded attacks on science education. To provide a little insight as to the Institute’s shameless objectives, consider that their mission statement outright states that the “point of view Discovery brings to its work includes a belief in God-given reason;” and that Discovery Media includes in its mission “to utilize every form of available media to present the reality of God's existence through compelling scientific evidence and academic research". Irrespective of one’s personal religious beliefs, sound scientifically minded inquiry can not be born of blatant biases and preconceived notions of causation. This is simply not how science works. To say that the Discovery Institute may be susceptible to high rates of confirmation bias is giving them too much credit. Speaking of biases, yesterday I reported that my in-home showing of Darwin’s Dilemma was courtesy of the Trinity Broadcast Network (TBN). Although you might be inclined to think that TBN suffers from the same religious biases as the Discovery Institute, that doesn’t appear to be the case; TBN has an altogether different bias – one that favors cold hard cash.

The Trinity Broadcast Network is the largest Christian television network provider in the United States and has media holdings in more than 70 other countries. I can sum up TBN credentials in six words- “It was founded by Jim Bakker.” Yes, Jim Bakker the televangelist, Jim Bakker the accused rapist, and yes Jim Bakker the convicted felon. If more evidence of the TBN’s ill repute is needed ponder that they are proud proponents of the religious practice known as the ‘prosperity gospel.’ Basically, the prosperity gospel teaches that a sinner can be forgiven for her/his wrongs if she/he donates money to the network. Yes, TBN is selling admission into heaven! I’m not sure what the price is though… And unfortunately, I can’t tell you how much income TBN makes from selling moral amnesty, because they refuse to disclose financial information for public inspection, or for that matter to Christian watchdog groups. So, in addition to dumbing-down its adherents with fake-science, TBN also steals their cash. In the science community this is referred to as a positive feedback cycle; the more dumberest you become, the more money you lose.

Getting back to the science…

Yesterday, I described how the high production quality of Darwin’s Dilemma allows for a visually exciting and even captivating viewing experience. As scary as this may be to admit, it’s absolutely true. The film is by far the ‘best’ anti-science propaganda film I’ve ever seen. The animation, narration and scene transitions are smooth and coherent; pseudo-science and misinformation aside, the film is good enough to rival most any that would appear on National Geographic or the History Channel. In regards to the science content presented in the film, at least up to the Richard Dawkins quote, a skeptic with some understanding of evolution and paleontology will see it for what it is – creationism; however, if seen through an uncritical eye it would appear wholly informative. Indeed, even those with a general understanding of science may at first be drawn to accepting the film’s premise; this in large part due to the awe and wonder inherent to the Cambrian Radiation itself. However, at about forty minutes into the feature the film takes a creationist turn; this happens right around the Dawkins quote. After Simon Conway Morris’s critique of the pre-radiation fossil record, the screen gives itself to the quote;


“It is as though they were just planted there without any evolutionary history”

-Richard Dawkins


In my assessment, this snippet is the first serious indicator of the film’s underlying evil purpose. Not only does the above Dawkins line – while out of context - seem to suggest the existence of a ‘planter’ and a shortfall in evolutionary knowledge, but it also happens to be one of the most frequently ‘abused’ evolution quotes in existence. It has been used and reused by creationists and fundamentalists the world over. This assertion can be verified by simply copying and pasting the whole sentence into a Google search engine; undertaking this exercise, I got back more than 10,000 hits. Incidentally, the quote itself has been clipped from page 229 of Dawkins’s 1996 book The Blind Watchmaker; when in context the quote is used in explaining that both he (Dawkins) and Stephen Gould agree that one, the pre-radiation fossils are few, and two, that the thin fossil record is no way indicative of divine intervention. Far from an admission of divine creation, the quote is used in The Blind Watchmaker to affirm that even biologists with differing perspectives on evolutionary mechanisms (see the citation below for an independent assessment of their incompatibilities) wholeheartedly endorse evolutionary agents as instigators of the Cambrian Explosion. At any rate, in Darwin’s Dilemma the Dawkins quote is used simply as a cap to Simon Conway Morris’s testimony, from there the film moves on to Creationism’s most hated of scientists – Charles Darwin. There we learn about the origins of Darwin's 'dilemma.'


ONCE AGAIN GETTING A BIT LONG... TO BE CONTINUED...


Reference:
Shanahan, T. (2001). Methodological and contextual factors in the Dawkins/Gould dispute over evolutionary progress Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences, 32 (1), 127-151 DOI: 10.1016/S1369-8486(00)00025-X

Darwin’s Dilemma, Creationist Propaganda and Corrupt Christians

Earlier this week the Trinity Broadcasting Network aired the Discovery Institute’s film ‘Darwin’s Dilemma: the mystery of the Cambrian fossil record.’ The feature length, allegedly-documentary movie has been promoted as an exploration “of the Cambrian explosion and the scientific controversy that still surrounds it.” Because of the evolutionary and science-based subject matter dealt with by the film, I thought that a private screening was in order, so when Saturday afternoon rolled around, I parked myself on the couch with a couple slices of cold pizza and hit play on my DVR’s remote…

Wow, the film really blew me away! To set the stage, let me first explain that being an enthusiast of science and nature documentaries, my DVR is pre-programmed to search and record all shows that include certain key words in their descriptions or titles. Occasionally, these key words, like ‘evolution’ or ‘fossils’ for example, result in the unintentional recording of creationist crap, and more often than not, this crap comes from the Trinity Broadcasting Network (TBN). About twice a week, the TBN broadcasts ‘science education’ programs with devious names like “Teaching Origins Objectively;’ but these shows don’t usually pose much of an inconvenience. They’re not a problem because I’ve conditioned myself to delete these recordings the very second that a party line or half-truth is identified – thus I rarely need to endure more than five minutes of these mostly low quality, poorly produced and obviously disingenuous shows.

Getting back to ‘Darwin’s Dilemma,’ as I started to watch, I was instantly caught off guard by the film’s production quality! The imagery was great; at the opening there was a well-animated Anomalocaris swimming happily in the Cambrian sea, and then after failing to out-swim an undersea avalanche, he was vividly buried and fossilized. Anomalocaris was an ancient animal that resembled a cross between a trilobite and a modern shrimp; it inhabited the world’s oceans about 520 million years ago. Comforting me through the Anomalocaris’s life and death drama was a spirited music score and a narrator that spoke with clarity and ease, like a wise grandfather detailing a long forgotten tale. As I continued to watch the paleontological spectacle unfold, I listened carefully to my knowledgeable patriarch, waiting for mention of a god, intelligent design or other clue to the movie’s shifty agenda – but it didn’t come.

I continued to watch...

Then a quote appeared on the screen;

"The Cambrian Explosion was the most remarkable and puzzling event in the history of life…” -Stephen Jay Gould

At first glance I thought that the creationist gig was up; but then, after a moment’s thought, I found myself in agreement with statement. The Cambrian Explosion was a pretty significant event, and although Stephen Gould’s quotes are often mined and used out-of-context by religious evil-doers, this wasn’t the case in this situation… The Cambrian Radiation was – and is – puzzling. I kept watching.

The story line moved from the demise of the introductory Anomalocaris to the history of the famous Burgess Shale. The narrator, while seamlessly transitioning between historic black and white photographs, elaborated on the rarity of unearthing quality fossils from geologic strata, he then verbally underlined the scientific value of those recovered from Canada’s Burgess Shale. He discussed Charles Walcott’s field seasons and the paleontological digs key to uncovering the mysteries of the Cambrian metazoans.

Then the film flashes to Cambridge University where we meet evolutionary biologist and renowned Cambrian expert Dr. Simon Conway Morris, whom promptly describes the Burgess fossils as “miraculous.”

I cringed.

I’d be willing to wager that Morris didn’t intend the word “miraculous” in the same sense that it is frequently used by the religious minded, but non-the-less I felt a deepening sickness come over me. Simon Conway Morris is a widely respected scientist, and he has openly explained that he participated in the ‘Darwin’s Dilemma’ film while unaware that it was to be torqued and twisted into pseudo-science. Unfortunately, had I not known about Morris’s plight, his cropped dialogue in the film would seem nothing short of fully endorsing the Intelligent Design scheme - truly a shame.

As the Cambridge interview proceeded, Simon Conway Morris went on to congenially list many of the questions and difficulties surrounding the study of the Cambrian Radiation Event. As I listened to his enthusiastic detailing of a lacking pre-Cambrian fossil record, poorly understood Proterozoic ecology and complications arising from the embryological development of animal body designs, I became aware that although Morris has hundreds of published articles to his credit - most of which offer answers to the very questions he lists in the film - none of his studies or findings are being mentioned. As one example of many, I recall a 1998 piece in which he specifically criticized “blanket assertions” about the Cambrian radiation. In the film Morris was being portrayed as an expert with no answers; furthermore, in the process of describing the past blockades to science’s Cambrian comprehension, he was actively shooting down out-dated notions about the radiation event. The end result of the exchange was a sneaky, almost imperceptible ‘time shift’ during which Morris’s critiques of science-past are superimposed on science-current. His onscreen persona is presented as asserting that modern biology has no way of explaining what happened during the Cambrian Radiation. In primary support of this false-claim is a reported lack of fossils predating the Cambrian diversification – a lack of intermediate fossils between pre-Cambrian protozoa and the rise of the Cambrian’s multicellular animals.

Just as Morris’s on-film character convinces the audience that the Cambrian fossils are “miraculous” and without predecessors, a new quote takes the screen;

“It is as though they were just planted there without any evolutionary history…” -Richard Dawkins


CONTINUED IN PART 2 - HERE


Morris, S. (1998). The evolution of diversity in ancient ecosystems: a review Philosophical Transactions of the Royal Society B: Biological Sciences, 353 (1366), 327-345 DOI: 10.1098/rstb.1998.0213

Wetland Plant of the Week #35

Aronia arbutifolia

Red Chokeberry

The red chokeberry is a medium sized shrub displaying minimal branching, gray bark and alternately arranged leaves. It’s one of two species of Aronia found in the eastern United States; the other species being the black chokeberry (A. melanocarpa). Aronia arbutifolia is common to stream banks, seepage slopes and hydric flatwoods that possess sufficient water to satisfy the plant’s Facultative Wet habitat preference. The leaves of the plant have a visible gland at the tip, a toothed margin and small red or purple spots along the midrib. The white-to-pink flowers emerge in spring and exhibit five petals. In addition to the attractive flowers, the aesthetically pleasing bright red berry-like fruits of Aronia arbutifolia have made it popular with horticulturalists as an ornamental.

Aronia arbutifolia is one of about 3000 species included in the Rosaceae Family. Despite the rose family’s general familiarity with both botanist and non-botanist alike, the group’s phylogeny is not understood all that well. Our current understanding of the Aronia Genus is in large part derived from the sequencing of several nuclear and chloroplast loci back in 2007. That study placed the chokeberries in the Maloideae subfamily. This Maloideae subfamily also contains the genus Malus (crab apples) and for that reason is sometimes referred to as the “apple group.” Although resolution of the group’s phylogeny has somewhat improved since then there is still plenty of work to do in understanding their evolutionary past.

The plant photo was taken two weeks ago near Panama City, Florida.

Potter, D., Eriksson, T., Evans, R., Oh, S., Smedmark, J., Morgan, D., Kerr, M., Robertson, K., Arsenault, M., Dickinson, T., & Campbell, C. (2007). Phylogeny and classification of Rosaceae Plant Systematics and Evolution, 266 (1-2), 5-43 DOI: 10.1007/s00606-007-0539-9

The Discovery Institute Sues CA Science Center

The Discovery Institute, a PR group that seeks to promote misinformation and quash science, has filed a lawsuit against a California Science Center for refusing to disclose certain public documents. The lawsuit follows the Science Center’s cancelation of a pro-intelligent design video at their IMAX Theater.

The film in question, “Darwin’s Dilemma: The Mystery of the Cambrian Fossil Record,” features evolutionary scientist Simon Conway Morris - a recognized expert on the Cambrian Explosion and the Burgess Shale. Morris’s involvement in the film has raised questions, though he has stated during interviews that he wasn’t aware the film was a creationist documentary until after its release.

“Darwin’s Dilemma” was broadcast earlier this week on a fundamentalist christian network that’s included with my DirectTV subscription; the movie anxiously sits on my DVR awaiting review – I’m curious to see Morris’s role in the propaganda.

For more info on the suit see this news article.

To read more about the Morris controversy click over to this September post at Laelaps.

Murderous Insights into Carnivorous Vegetables

Wow!

I felt compelled to post the below link.

The linked (free) paper was recently published in the Botanical Journal of the Linnean Society. It makes the argument that there are more carnivorous plants in nature than are currently recognized by botanists.

It also describes some plants, and plant characteristics, that might represent ‘proto-carnivorous’ tendencies.


Hmmmmm…


Definently worth a look; here’s the abstract:
Darwin's interest in carnivorous plants was in keeping with the Victorian fascination with Gothic horrors, and his experiments on them were many and varied, ranging from what appears to be idle curiosity (e.g. what will happen if I place a human hair on a Drosera leaf?) to detailed investigations of mechanisms. Mechanisms for capture and digestion of prey vary greatly among the six (or more) lineages of flowering plants that have well-developed carnivory, and some are much more active than others. Passive carnivory is common in some groups, and one, Roridula (Roridulaceae) from southern Africa, is so passively carnivorous that it requires the presence of an insect intermediate to derive any benefit from prey trapped on its leaves. Other groups not generally considered to be carnivores, such as Stylidium (Stylidiaceae), some species of Potentilla (Rosaceae), Proboscidea (Martyniaceae) and Geranium (Geraniaceae), that have been demonstrated to both produce digestive enzymes on their epidermal surfaces and be capable of absorbing the products, are putatively just as 'carnivorous' as Roridula. There is no clear way to discriminate between cases of passive and active carnivory and between non-carnivorous and carnivorous plants – all intermediates exist. Here, we document the various angiosperm clades in which carnivory has evolved and the degree to which these plants have become 'complete carnivores'. We also discuss the problems with definition of the terms used to describe carnivorous plants.


Click the citation below to view this free article:

Mark W. Chase, Maarten J. M. Christenhusz, Dawn Sanders, Michael F. Fay. Murderous plants: Victorian Gothic, Darwin and modern insights into vegetable carnivory. Botanical Journal of the Linnean Society, 2009; 161 (4): 329 DOI: 10.1111/j.1095-8339.2009.01014.x

Prehistoric Guinea Pigs from Egypt

A study recently published by the Proceedings of the National Academy of Sciences describes how modern day representatives of the Phiomorpha and Caviomorpha groups diverged approximately 37 million years ago.

The phylogeny detailed in the article was derived through combination of biogeographical, genetic and fossil evidence, and serves to demonstrate that the Caviomorpha, a group that includes modern-day guinea pigs, separated from the Phiomorpha during the early Eocene epoch between 34 and 40 million years ago.

Prior to divergence, both groups were bound by the rodent infraorder Hystricognathi and were restricted to Afro-Arabia. In sync with the rise of modern mammals during the Eocene, members of the Cavimorpha parted ways with the Phiomorpha and emmigrated to South America, possibly by rafting or other chance dispersal event. The Phiomorpha remained behind in Afro-Arabia where they radiated into a variety of genera, including the extant genus Thryonomys – commonly known as cane rats.

Key to the study’s finding was morphological examination of fossil assemblages excavated from the Fayum Depression of northeast Egypt. The mandibular and maxillary fossils recovered from the site revealed a mixture of both primitive and derived features. This fossil data was amalgamated with independently calculated genetic estimates to narrow the timing for the early Eocene divergence.


Sallam, H., Seiffert, E., Steiper, M., & Simons, E. (2009). Fossil and molecular evidence constrain scenarios for the early evolutionary and biogeographic history of hystricognathous rodents Proceedings of the National Academy of Sciences, 106 (39), 16722-16727 DOI: 10.1073/pnas.0908702106

Evolution is in the Veins of Our Captors

The human race has been enslaved by evolutionarily superior organisms.

In the beginning there was but inorganic matter. From these lifeless substances came the organics which later gave rise to legion-minded protobionts. The protobionts in time beget prokaryotic cells, and with this pivotal step the guiding hand of evolution took charge and asserted the symbiotic conception of the eukaryotes. Since the self-proclaimed commencement of evolution’s command, the human ancestral line has arrogantly clambered from simple beginnings towards its present summit; however, in their hasty climb humans failed to notice their captor’s gradual rise to global dominance.

Abiogenesis from inorganic matter to life was the first of several milestones in our current masters’ conquest of the animal kingdom. During these first tentative steps, the primitive ancestors of the tyrannical angiosperms underwent adaptation to feed on the then abundant atmospheric carbon dioxide. Through undertaking a process known as photosynthesis, some early plant-forms gained reproductive advantage and quickly out-competed their rivals. In time, their numbers became so great that oxygen – a byproduct of photosynthesis - accumulated in the biosphere to such extent that it triggered a catastrophic transition to an oxygenated planet. In hindsight, this rapid transition, called the ‘Great Oxygenation Event,’ can be viewed as a first step in the angiosperms’ selfish remaking of the Earth, and as foreshadowing the eventual enslavement of all humankind.

Initially, constrained anatomy affectively limited the plants’ ability to channel the xylem tissues required for harnessing the sun’s rays. Xylem tissues are essential to photosynthesis because it is their job to convey water and nutrients throughout the plant. Early plants lacked sufficient internal structure and architecture to serve as pathways for xylem transport; this physically restricted the amount of energy that could be generated through photosynthesis. In other words, because of a lack of adequate venation, the radiation of angiosperms was kept in-check. However, this all changed during the Cretaceous Period.

Over the course of evolutionary history, natural selection tinkered at the physiology of the angiosperms, incrementally improving their clumsy and inefficient application of photosynthesis until eventually, about 120,000,000 years ago, the density of the angiosperms’ veins dramatically increased by 300-400%. The upsurge in venation meant that the plants’ xylem tissues more frequently made contact with individual plant cells; this pushed the capacity of the angiosperms’ energetic processes far beyond what they could achieve previously. Newly acquired energy surpluses were promptly invested in reproduction and as a result angiosperm populations exploded the world over.

Having maximized their capacity for photosynthetic production, the angiosperms diversified and radiated into an enormous variety of species, and in the process of doing so molded the world’s landscapes and ecosystems to meet their own needs. Finally, about 10,000 years ago, the plants made their strike against Homo sapiens.

Like bee’s manipulated into service through bribes of nectar, plants lured humans with delicious offerings. They willingly sacrificed their leaves, roots and stems to obtain the blind loyalty of humanity. Since the Neolithic Agricultural Revolution, some 10,000 years ago, the people of Earth have been enslaved by angiosperms.

People have transplanted angiosperms on every continent, expanding the plants distribution beyond what they could have accomplished on their own. Humans actively clear thousands of square miles to seed monocultures for the most powerful of the angiosperm aristocracy. Humans reap minerals from the earth to compose fertilizers for these overlords. As if afflicted with Stockholm Syndrome people blame themselves and the burning of fossil fuels for recent rises in atmospheric carbon dioxide… It’s too coincidental; it must be part of the angiosperms’ monstrous plan!

Now, with implications ranging into what seems like science fiction, humans apply molecular genetics to enhance angiosperm DNA… When will the human race be freed?


Brodribb, T., & Feild, T. (2009). Leaf hydraulic evolution led a surge in leaf photosynthetic capacity during early angiosperm diversification Ecology Letters DOI: 10.1111/j.1461-0248.2009.01410.x

Greg Laden is Hosting Circus of the Spineless 45

Circus of the Spineless #45 is up over at Greg Laden’s Blog.

It’s a one-stop shop for the best in spineless blogging.

Click-over and take a look!

The Circumvention of Compulsory Sex

Males are sexually coercive. During initial encounters with the opposite sex, they will go to great lengths to impress and entice; they’ll offer gifts, sing, dance, and do whatever else is necessary to win a female’s affections. However, should these preliminary advances be rejected, the males from a multitude of different animal species will unhesitantly apply the tactics of deceit, intimidation and even brute force to satisfy their reproductive drives.

Through forced couplings males enhance the spread and flow of their genes within the larger gene pool. By mating with both those females that accept his flirtations and those that don’t, the total number of a male’s sired offspring in the population is increased. This strategy provides the male with a reproductive leg-up over his rivals - the other males in the population. Energetically speaking, the tactic of repeated mating comes at a bargain price, because unlike females, males don’t usually incur the taxing reproductive expenses associated with pregnancy, tending to offspring, or for that matter even production of female reproductive cells – the ova.

In most vertebrates, female and male gametes differ in size and structure; this phenomenon is referred to as anisogamy. The female gametes (ova) are larger in size than that of the male gametes (sperm). Ova are larger because, in addition to containing the female’s DNA, they provide all of the nutrition and protection required for the resulting embryo’s development. Spermatozoa by contrast are merely vehicles for delivering the male genetic compliment and are far less costly to manufacture and send. In other words, sperm are cheap, eggs are expensive.

Although cheap sperm and compulsory sex are effective tools for propelling the male’s genes into the bodies of future generations, they do so with little regard for the reproductive goals of the female’s genome. Recall from yesterday’s discussion, that the female gender of a species is typically better positioned to be the ‘chooser’ when selecting potential sexual partners; this is in large part due to the above described costs associated with eggs, pregnancy and child rearing. Through selecting only the most fit, well-matched mates, females are able to reap the benefits of their own inclusive fecundity and improve their own reproductive fitness. In opposition, sexual coercion eliminates the female’s choice and adversely impacts her reproductive fitness.

Reproduction drives the process of natural selection. As a consequence of this biological tenet, a decline in a group’s reproductive fitness is countered in one of two ways; extinction or adaptation. Females challenged with deteriorating fitness often undergo morphological and behavioral adaptation to mitigate for the coercive sex practices of males. Just as selection favors the advancing genes of the male, it also favors those traits that enforce the female’s fitness. As weapons in the back-and-forth battle for reproductive victory, the female may brandish many weapons; she may practice avoidance, she might form coalitions with other females or a dominant protective male, she could incite male-male combat, or her physiology could adapt to delay egg deposition or to interfere with the transfer of the coercive male’s sperm. The behavioral and physiological possibilities are nearly endless.

As a case in point, the female ‘agile frog’ (Rana dalmatina) shares a habitat with two-different species of male frogs; the males of her own kind, and those called ‘European common brown frogs’ (Rana temporaria). Both species of male frogs utilize coercive sex as a reproductive tactic, and both will force themselves on the female agile frog. However, if she is subjected to forced amplexus (frog sex) by the male ‘common brown,’ the resultant discharge of expensive eggs will not be profitably fertilized. Because the common brown is a different species, the fusion of his sperm with the agile frog’s ova will not result in the development of viable frog embryos. In this instance, coercive sex results in the female wasting an entire clutch of eggs that could have potentially carried her genes into the future. To mitigate for the loss of eggs by forced sex, the female agile frog will ‘intentionally’ delay egg-laying in hopes of discouraging the male’s incessant reproductive efforts. If after time the male doesn’t seem to loose interest, the female will release a reduced quantity of eggs. Thinking his mission a success, as a response the male will then release his sperm onto the eggs and part ways in pursuit of the next female. By using the somewhat sneaky, though affective, reduced-eggs scheme, the female exerts ‘cryptic choice’ as a method of insuring her reproductive investment and safeguarding her fitness. This case highlights one of many examples in which a female has manipulated a compulsory sex encounter to circumvent a potential decrease in her fitness.


Hettyey, A., Baksay, S., Vági, B., & Hoi, H. (2009). Counterstrategies by female frogs to sexual coercion by heterospecifics Animal Behaviour, 78 (6), 1365-1372 DOI: 10.1016/j.anbehav.2009.09.006



Rana dalmatina Photo by Fabio Turel

The Sexy Stench of the Opposite Sex’s Genes

Also posted to The Faster Times

There are many ways to attract potential sexual partners. Some animals show-off with elaborately choreographed song and dance routines, others entice through the display of brilliant coloration, and yet others forego personal flare and solicit the opposite sex by bribing them with food or real-estate. Although the methods utilized to attract mates vary widely, the drive to reproduce is hard-wired in all of life. The genetic compliment held by each organism extends its reach into the external world with aspirations of replication and conquest. According to some recently published research, females of one primate species use their nose to select those sexual partners hosting the most apt of these aspirant genes.

Generally speaking, the female gender of a species is often better positioned to be the ‘chooser’ when selecting potential sexual partners; they have the final say as to how far a relationship proceeds. Females are conferred the gift of mate-preference because they, unlike males, take on the costly biologic and energetic burdens associated with pregnancy and the rearing of young. In the natural world, toting around offspring and locating ample food-stuffs to feed those progeny represent liabilities to the mother. Because she endures these hazards, she is provided the opportunity to decide with which males to mate. But given that females are the ‘deciders,’ on what grounds are their mate-selections made, and what criteria do they weigh and measure prior to committing to a costly reproductive venture?

‘Choose, but choose wisely’ is the mantra of the discriminating female when seeking-out male suitors. Through selecting only the most fit, well-matched mates, females are able to reap the benefits of their own inclusive fecundity and be better enabled to garner the evolutionary dividends of more numerous and healthy offspring. In regards to the beastly species known as Homo sapiens, human fertility clinics can utilize modern molecular techniques to perform genetic assessments; however, ‘good genes’ typically aren’t identified by non-human kinfolk in laboratory settings. Rather than admission to fertility clinics, in the wild evaluation of mates is undertaken on the fly using an organism’s innate sensory capabilities.

In its simplest form, avoidance of certain physiological cues such as developmental deformities can aid a female in filtering-out unworthy genetic sets. Unusual appearances, irregular gaits or abnormal vocalizations of male callers tend to stand-out to females and are almost always avoided. In other cases, elaborate courtship rituals, male-to-male fighting or induced ovulation tactics may be summoned into play as means of determining the superlative mate. Some primate species, like the mandrill for example, use their nose to guide their choice of sexual partners.

Mandrills are a variety of Old-world monkeys that inhabit parts of Equatorial Africa. They are highly social primates and can be found living in troops consisting of more than 1000 individuals. Recent research conducted jointly by scientists from the United Kingdom, France and Gabon suggests that the female mandrill is able to read the genome of potential mates through her nose. Because the male mandrills don’t offer anything to the females as a direct benefit – like the before mentioned tactic of bribing with food – the females endeavor to mate with those males possessing different, though complimentary, genetic characteristics.

By reproducing with partners holding diverse genomes the female improves the robustness of her line’s immune system. More specifically, the major histocompatibility complex (MHC) is a multi-gene family found within the genome of vertebrates that plays a key role in facilitating the immune system’s response to disease. Basically, by possessing greater diversity in the MHC, an animal’s immune system is more enabled to combat a larger range of foreign proteins. Through reproducing with male mandrills having a differing MHC, the female mandrill enhances her offspring’s capacity to thwart illness and disease. This ability to stave sickness is critical for an animal that resides in a hot, wet habitat with an abundance of bacteria and parasites. As stated previously, she distinguishes diverse MHCs through application of her olfactory apparatus – her sense of smell.

Male mandrills attract the females by rubbing their scent-glands against trees and rocks throughout their home territory. This effectively publicizes their MHC for the female’s review. If after assessing the male’s advertised MHC the female determines that the male possess sufficiently aspirant genes, she will choose him as a sexual partner.


SETCHELL, J., CHARPENTIER, M., ABBOTT, K., WICKINGS, E., & KNAPP, L. (2009). Opposites attract: MHC-associated mate choice in a polygynous primate Journal of Evolutionary Biology DOI: 10.1111/j.1420-9101.2009.01880.x

Photo Courtesy of Joyrex

Any Evolution Bloggers Care to Feature a Post?

Any fellow Evolution Bloggers Care to Feature a Post?

The online news site ‘The Faster Times’ has a new evolution correspondent – me!

In addition to posting original write-ups I’m afforded the opportunity to feature links to other evolution related blogs and/or news stories. If anyone has a post they’d like to share, let me know in the comments below, or via email.

FYI - I’ve already snatched a couple of posts from Catalogue of Organisms, Deep-Sea News and Myrmecos (a few of my favorite blogs)

Also, to serve as a ‘test post’ and introduction at the site, I posted the below short narrative a few minutes ago.


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Why Evolution?

Having just taken on the post of Evolution Correspondent here at The Faster Times, it seems fitting that I begin with a justification for this column’s existence.

Evolution is life’s central theme, and, as such, it has maintained a preeminent standing in the human mind; it holds our attention more than any other science. Even the earth’s surrounding cosmos in all of its complexity, though assuredly fascinating, is often no more than a transient curiosity to those of us not actively employed in the field of astronomy or otherwise engaged in the labors of the physical sciences.

As it happens, astronomy is neglected as a casual social topic for precisely the same reason that biological evolution is embraced. Although both sciences are formally approached through the tenets of systematic inquiry, and informally admired for their ephemeral beauty, evolution - unlike astronomy - holds in its grasp ideas key to finding our place - our human place - in the larger scheme of things. Said differently, even supernovas are eclipsed by the human ego. Whereas the scale and inorganic composition of the stars may preclude many of us from connecting to them on personal and philosophical levels, we all have opinions on the questions of biological origin, design and purpose. How did we get here? Where do we fit in nature? Where are we heading? These are the questions we strive daily to fit into our senses of self, our morals and our politics.

Sex, lust, sympathy, altruism, familial bonding and the rise of human consciousness are but a minute sampling of the myriad of human-centric issues that can be interpreted and better understood through biological evolution. And this says nothing as to the magnificence of nature apart from humankind; from bacteria to elephants, evolution speaks volumes. It explains why the grass is green, how viruses infect, how bats see with their ears, and why cheetahs hunt. Oak trees, tyrannosaurs and humans - evolution explains it all.

As an ecologist, the interpretation of the natural world is a prerequisite of my profession; however my fervor for the subject arises not out of necessity, rather it is born of an innate curiosity that is compounded by a heartfelt awe of nature’s splendor. Nonetheless be forewarned, though evolution is a truly passion-felt study I am not a writer by trade, and evolution’s life and death struggles are sometimes difficult to accurately convey in words. This is why I encourage you all to send suggestions, comments, criticisms, or personal insults deemed appropriate. Critiques can be included here as comments, or sent to me via email; a response will be returned for each in a reasonable amount of time.

A Darkiling Beetle, a Wasp, a Fritillary and an Egret

Random photos from the field; taken last week just south of Tampa, Florida.

Possibly Isomira pulla ???

A species of the Sceliphron genus ???

A couple of Gulf Fritillaries; Agraulis vanillae

Great Egret; Casmerodius albus

Wetland Plant of the Week #34

Limonium carolinianum

Sea Lavender

Despite its common name ‘sea lavender’ is a member of the Plumbaginaceae Family, which means that it isn’t really a ‘lavender’ at all, as lavenders belong to the Lamiaceae Family. One of the plant’s unique characteristics is that it’s one of only a handful of the Limonium genera’s 120 species with a range limited to North America; the majority of the genera’s members show a much more global distribution. Here in Florida, the Obligate can be found near saltwater or brackish marshes, or as with the one in the above photo, in mangrove swamps.

Limonium carolinianum is an herbaceous perennial with a woody rhizome and alternating leaves. The leaves themselves are basal, generally elliptic in shape and have a leathery feel when touched. The flowers display five stamens, and a five-lobed, whitish colored calyx with a corolla that ranges from blue to lavender. The fruits of the sea lavender bear a single maroon colored seed, which as with the plant’s range mentioned above, represent another unique characteristic. More specifically, the seeds’ morphology and structure have undergone adaptation as to tell-the-tale of plant’s favored mode of geographic conquest.

The brownish-red seeds of the sea lavender are relatively large and display a sheen that likely attracts birds. The plant’s habitat preference for saltwater proximal real-estate when combined with the sheen displayed by its seeds may work cohesively to facilitate dispersal of its genome. As Charles Darwin pointed out on page 361 of the Origin of Species,

“Living birds can hardly fail to be highly effective agents in the transportation of seeds.”

This is likely true of Limonium carolinianum, a plant species that has adapted to near-sea environments that are frequented by shore birds.

Biologically assisted seed dispersal mechanisms can be thought of as primarily working along one of two primary lines. One method of dispersal, called epizoochory, relays on seeds being externally attached to the hair, fur or feathers of animals. Once attached, the seeds are carried with the animal as it moves across the landscape. The second mode of animal derived seed transport is called endozoochory; in this instance the seeds are eaten by an herbivore or frugivore and then deposited elsewhere with the animal’s feces.

Although the possibility of water facilitated seed dispersal is not ruled-out, the seed morphology of Limonium carolinianum increases the plausibility for endozoochory.


FIGUEROLA, J., & GREEN, A. (2002). Dispersal of aquatic organisms by waterbirds: a review of past research and priorities for future studies Freshwater Biology, 47 (3), 483-494 DOI: 10.1046/j.1365-2427.2002.00829.x

Hints of a Catastrophic Paleoclimatic Event from Manny the Mammoth

In an effort to gain insight into the challenges posed by climate change, I just spent the last couple of hours watching the animated feature film “Ice Age 2 – The Meltdown.” The plot of the cartoon centers on a group of anthropomorphized prehistoric mammals (a mammoth, saber-toothed tiger, sloth and a halfwit saber-toothed squirrel) as they flee an impending flood and their certain extinction. Interestingly enough, the floodwaters in the movie purportedly result from a period of global warming and the associated thawing of their fictional ice-aged world. Initially, the characters in the film celebrate the rising temperatures with lakeside antics, but their clowning around comes to an abrupt end when they realize that their short-term fun-in-the-sun will inevitably end with substantial losses in lakeside real-estate, an ecosystem on which they’ve come to depend.

All considered I enjoyed the cartoon; mostly because of its paleoclimatological accuracy. Well, maybe it wasn’t all that accurate, but the underlying theme wasn’t too far-off…

Parallels between the feature and the real paleontological past can be glimpsed when consideration is given to the thermal fluctuations and water linked extinctions portrayed in the film. To explain, the impending floodwaters in the movie were precariously dammed by a mile-high glacial wall. It was the gradual disintegration of this frozen barrier that established the dramatic timeline for the lead mammals escape from danger. The waters bound by the glacial front had accumulated through the receding of the glacier itself, and should the wall be breached the waters would be freed to reap havoc. Although such a physical setting may seem a bit far fetched, it just so happens that between 12,900–11,500 years ago similar lakeside conditions may have contributed to the extinctions of numerous North American mammal species.

Characters from the ‘Ice Age 2’ ; glacier and glacial lake (Lake Agassiz?) in background.

During the Wisconsin glaciations about 12,000 years before the present, a massive continental ice sheet covered most of what is today the United States and Canada. As the Wisconsin came to a close, rising temperatures instigated its receding glaciers to form a colossal lake; roughly centered on modern day Manitoba. The lake was uniquely positioned in such a way that a combination of topography and its inclusive glacial blockades trapped the discharge of meltwater. The glacial melt, being unable to drain, resultantly accumulated in a water body that covered nearly half of a million square kilometers – Lake Agassiz. As in the animated movie, once sufficient hydrology was achieved to overcome its restricting geography and ice, the water was released in a catastrophic flooding event of incomprehensible immensity. However, unlike the cartoon’s scripted drama, the direst impact to fauna 12,000 years ago wasn’t the risk of drowning; the biggest consequence of the flood was its affects to global climate.

The enormous quantity of water released from the rupture of Lake Agassiz’s glacial banks, as opposed to flowing directly southward, chose to exit by way of the Saint Lawrence River. Following the St. Lawrence, the freshwaters moved eastward and into the North Atlantic. Once in the North Atlantic, the vast icy water cooled the warmer North Atlantic Current, and rapidly diluted the saline gradients that help drive its heat-conveying waters. Known as thermohaline circulation, variations in ocean water density create flow patterns that convey heat from regions proximal to the equator to those areas located more pole-ward; the constituent variations in density are brought about by surficial heat and saline content. The rupture of Lake Agassiz impacted the thermohaline circulation of the North Atlantic Current, altered heat transfer to the northern hemisphere, and drastically changed the Pleistocene climate of the North American Continent. The rapid climate change associated with the Lake Agassiz event is known as the Younger Dryas stadial (a ‘stadial’ is the name assigned to a period of cooling temperatures).

During the Younger Dryas stadial, mean annual temperatures throughout large portions of the Northern Hemisphere plummeted by as much as five-degrees Celsius. The drop in temperature caused some regions to re-glaciate, despite what had until recently been a warming trend. Climate change forced ecosystems into flux, and likely contributed to the extinction of several genera of mammals – The End Pleistocene Extinction Event.

The End Pleistocene Extinction Event marked the end of the road for some of the characters portrayed in the Ice Age movie, saber-toothed cats, giant sloths, mastodons and similar mammals. As a matter of fact, a recent article in Science collaborated the extinction chronology for more than 30 genera of Pleistocene fauna; the study used data from FAUNMAP to determine that the extinctions occurred nearly simultaneously.

Although much is known about the Younger Dryas stadial, its exact contribution to the End Pleistocene Extinction is still largely a matter for debate. Complicating the issue is the immigration of Clovis people into North America at about the same time that the Younger Dryas was putting a strangle-hold on the climate. The Clovis may have participated in the mammals’ disappearance through hunting – the Overkill Hypothesis.


Faith, J., & Surovell, T. (2009). Synchronous extinction of North America's Pleistocene mammals Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0908153106

Evolutionary and Developmental Biology - The Making of the Fittest

Sean Carroll lecturing on evolutionary and developmental biology. The talk is largely drawn form his book "The Making of the Fittest," which if you haven't read I'd highly recommend.

You'll want to fast forward to about 18:30 due to a lengthy wait before Sean's start and the removal of a copyrighted video used as an introduction.

From Promiscuous to Palatable, the Making of a Thanksgiving Day Entree

“For the truth the turkey is in comparison a much more respectable bird and withal a true original native of America... he is besides, though a little vain & silly, a bird of courage, and would not hesitate to attack a grenadier of the British guards who should presume to invade his farm yard with a red coat on.” (Benjamin Franklin, 1784)

As demonstrated by the above quote, Benjamin Franklin admired the turkey for its courage, and although the bird may have been somewhat “vain and silly,” in his evaluation it would have served as a better emblem for the newly constituted United States than does the bald eagle, which Franklin would describe in the same transcript as “a bird of bad moral character” and as one that “does not get his living honestly.”

In reflecting on Franklin’s impeachment of the eagle’s morality, it becomes blatantly apparent that his basis for turkey endorsement was not derived from the appraising of the two birds’ sexual fidelity or familial loyalty. If Franklin would have objectively weighed the family values displayed by the bald eagle against those shown by the turkey, he would have undoubtedly praised the eagle for its habit of committing to more-or-less monogamous relationships, and he would have scorned the turkey’s shameless and promiscuous lifestyle.

Despite Franklin’s misinformed backing, the mate-choosing habits of the wild turkey (Meleagris gallopavo) have long been known to diverge from those standards held by the majority of human cultures. Turkeys are sexually dimorphic with the seemingly arrogant males of the species being substantially larger than the females and displaying a showy, red-colored head and neck. Vulgarly hanging from the head of the beastly male are fleshy folds of skin called ‘wattles’ that are composed of erectile tissue that can be engulfed by blood to signal agitation or arousal. Changes in the size and color of wattles can be paraded in combination with raised feathers and loud boisterous calls (i.e. gobble, gobble) to signal potential mates or to intimidate rivals.

Furthermore, in contrast to the typically monogamous bald eagle, turkeys commonly practice polygyny; this means that a single dominant and territorial male will guard a harem of hens. However in some cases, particularly when local populations become over-crowded, small licentious groups of roving males may share a territory – though, of course, they’ll still scrap for female access.

Through mating with multiple females, and guarding those females from rivals, male turkeys, being insensitive to the reproductive aspirations of others, selfishly increase the number of offspring in the population that bear their genes - said differently, their genes experience greater frequency in the gene pool. Genes are also important to the self-indulgent female turkey.

The male’s propensity to mate with multiple females means that he has little time to contribute towards the proper rearing of young, or to providing any type of direct benefit to the female. Not foreseeing any direct benefits herself, the female turkey grants sexual access to those males with the best and brightest displays. In addition to wattles and the red-colored face and neck mentioned above, male turkeys flaunt feathers with red, green, gold and iridescent coloration. The overall brilliance of the male’s colors provides the female with clues as to his health and genetic makeup.

Despite the dominant male’s watch, the female turkey - far from being chaste herself - also strives to maximize the occurrence of her genes in the population. Like the male turkey, she’ll mate with multiple partners. To illustrate the female’s wanton ways even more, consider that in a study conducted by Berkeley’s Alan Krakauer about 45% of turkey nests sampled during a study of the turkey’s genetic reach were found to contain eggs derived from multiple parentages. The genetically sampled broods contained not only eggs from multiple males, they also were found to contain the eggs from multiple females!

Even beyond the female turkey’s flagrant granting of sexual access to multiple males, the California study revealed that females practiced a quasi nest-parasitism during which they would mate with the father of a neighbor hen’s clutch, and then lay the eggs from that clandestine joining in the nest of the neighbor – leaving the ‘cheated spouse’ to care for the young born of her rouge and mischievous mate’s digressions.

In light of Benjamin Franklin’s personification of the turkey as a “respectable bird,” it becomes difficult to comprehend the process that he undertook in achieving his conclusions of 1784… Unless of course in addition to his many other famous accolades, Franklin also happened to be a knowledgeable naturalist. Perhaps he wasn’t making a statement about the turkey’s morals and ethics; maybe he was making a statement about the bird’s fecundity…

Or, as yet another possibility, perhaps the vain, silly and promiscuous turkey holds more commonality with the citizenship than we care to admit…


KRAKAUER, A. (2008). SEXUAL SELECTION AND THE GENETIC MATING SYSTEM OF WILD TURKEYS The Condor, 110 (1), 1-12 DOI: 10.1525/cond.2008.110.1.1

Sex was a Costly Affair for Ceratopsian Dinosaurs

In a recent article published in The Anatomical Record several scientists, including Florida State University’s resident dino-osteologist Gregory Erickson, constructed a life table for a population of 80 bird-hipped dinosaurs.

Note, a ‘life table’ is a common tool used by population ecologists/biologists to interpret the birth-to-death maturation cycle of an organism. Essentially, a life table can be thought of as a listing of a population’s members with a corresponding age identified for each individual. Through examination of how the table’s age-ranges are distributed scientists can make inferences regarding the population’s ecology.

Drawing reliable conclusions on the subject of population-level processes can be difficult, particularly when that population happens to be extinct and is only known from the fossil record. Without numerous, quantitatively significant, representatives from a population, discussions of maturation rates, reproductive cycles and mortality rates are all but impossible. However, a mass kill event documented in the Lujiatun Bed of the Lower Cretaceous (Yixian Formation, Liaoning Province of China) provided the Erickson led team with the rare opportunity to do just that, study the demography of an extinct population of dinosaurs – specifically the species Psittacosaurus lujiatunensis.

Compared to the ‘lizard-hipped’ dinosaurs (saurischians) relatively little research has been undertaken in understanding the life history and population dynamics of the Ornithischia (bird-hipped), this makes the case of P. lujiatunensis all the more significant. Through histological analysis of the growth rings found within the fossil bones of the ceratopsians, – analogous to counting the growth rings in a tree – Erickson was able to estimate the age of each population member; the frequency of the age-ranges were then correlated to body size estimates. The result was that, like modern birds and mammals of comparable size, the life history of Psittacosaurus lujiatunensis reflected a pattern in which

“[h]igh attrition in young individuals gives way to lower stabilized values once a threshold size is obtained; however, later in ontogeny mortality rates increase (typically from the effects of senescence) leading to the extinction of the cohort.”

In other words, risk of death was found to be at its greatest when the dinosaurs were young and small – possibly because of vulnerability to predation. Once achieving a certain size and becoming less vulnerable, mortality rates decreased. Mortality risks would then increase again as the dinosaurs got old; through the natural ageing process the senior members of the population would once again become vulnerable to predators, disease, and etcetera.

In addition to the vulnerable young and old members of the Psittacosaurus lujiatunensis population, incidences of increased mortality were also found for those ceratopsians around the age-range associated with reaching sexual maturity. In this case, energy and resources devoted to the pursuit and winning of mates, as well as the rearing of young once a mate was found, likely conspired to cause escalated mortality levels during the reproductive years.


Erickson, G., Makovicky, P., Inouye, B., Zhou, C., & Gao, K (2009). Initial Insights Into Ornithischian Dinosaur Population Biology
The Anatomical Record, 292 (9), 1514-1521