SciBlogs

Archive 2009

misleading medical-science stories – & why most published research findings are false Alison Campbell Dec 28

2 Comments

It’s been pointed out to me that this post could be construed as dissing the EPP drug & its producers. This was not in any way my intention – the post was about the fairly poor reporting around a couple of medical science stories, ending with a wish that science journalists were more aware of the fact that much medical research tends (for a whole lot of perfectly good reasons!) to be ‘wrong’. (Hopefully this awareness would be followed by a decline in the hyperbolic reports about new breakthroughs & discoveries…)

Two stories in this morning’s Herald caught my eye – & made me sigh. One announced the imminent release of a ‘UV vaccine’, & the other elevated another fruit to the level of ‘superfood’. Both were examples of how not to present research findings to the public.

The first (originally from the UK paper The Telegraph) carries the headline UV protection drug prevents skin cancer & the first paragraph tells readers that [an] anti-sunburn drug that protects even the fairest-skinned people from skin cancer and ultra-violet rays could soon be made available to the public. It’s difficult to assess all the claims made in the article because, unfortunately, the actual research study on which this story appears to be based has yet to be published. However, there are a number of statements in the story that set my teeth on edge (beginning with ’the results [of the study] will be published soon’).

The drug in question (afamelanotide) has been developed by an Australian company to treat people with a condition called EPP, or  erythropoietic protoporphyria. Porphyrins are chemicals involved in a number of important biochemical processes within the body, including the production of red blood cells. The metabolic pathway your body uses to produce porphyrins can be interrupted by any one of several different mutuations, with the result that intermediate chemicals build up in the body. In the case of EPP (a rare disorder that affects less than 1 in 200,000), a mutation sees an excess of the chemical protoporphyrin in patients’ blood & skin – & in the skin it absorbs and reacts with light to give an extremely painful burning sensation. Individuals with the most severe (& extremely rare) form, congenital EPP, can’t tolerate any natural light, as their skin blisters & burns on exposure. Not nice at all.

It sounds as if the drug – which has just gone through a 12-month trial in EPP patients – acts to stimulate eumelanin production in the skin (not ‘between light and a person’s skin’, as the newspaper story would have it), providing a protective barrier against the worst of the sunlight. However, I couldn’t find anything in the company’s own available documents to suggest that it might also protect against skin cancer – and anyway, while skin cancer is more common in fair-skinned individuals, it does still affect those with more heavily pigmented skins. (A tan is not a 100% guarantee of immunity from skin cancer.) For example, the frequency of melanoma in African Americans is 1 in 100,000 (compared to 22 in 100,000 for US Caucasians). In any event, if afamelanotide did ‘prevent’ skin cancer, then you might expect to see it licensed  approved for this use – but the US FDA has approved it for treatment of further clinical trials in people with EPP, & this is how the company concerned sees it being used[it] is proposed that afamelanotide will assist those patients who are most severely affected by UV and light, with the aim of improving their quality of life.

So the absolute statement that the new drug ‘prevents skin cancer’ is misleading, at the least. And while the drug may well reduce the rates of skin cancer in EPP patients, where any sun exposure is damaging, there is as yet nothing to demonstrate that it would have the same protective effect in the wider population. Nor should it be marketed to that wider population, as it sounds as if there is the potential for damage to immune & cardiovascular systems unless use of the drug is carefully monitored. Unfortunately, this information comes at the end of the news story, which otherwise hypes up the new pharmaceutical to the population at large.

The other story (also not yet on the Herald website, but carried in The Guardian in the UK) is called Fruit could be answer to hospital superbug. The latest addition to the ‘superfood’ pantheon is the pomegranate (which must be something of an acquired taste – one which so far I have yet to gain). We’re told that [s]cientists have discovered the power of fruit as a potential new weapon in the fight against MRSA and other hospital superbugs. Now, methicillin-resistant Staphylococcus aureus (MRSA) is a real nasty, resistant to methicillin & other related penicillin-type antibiotics, so the finding that a novel treatment may be available is cause for cautious optimism. And apparently a combination of pomegranate rind, vitamin C, & a metal salt ‘greatly enhanced [the] infection-fighting properties’ of this particular fruit. But not against Staph.aureus - the study on which this report seems to be based used the a multidrug-resistant strain of the bacterium Pseudomonas aeruginosa (Gould et al. 2009). A picky point, but how hard is it to be accurate? Would this detract from the story?

The article quotes one of the research team as saying that "It was the mix that fantastically increased the activity – there was synergy, where the combined effects were much greater than those exhibited by individual components…"  And then goes on to say that The tests were conducted using microbes taken from hospital patients. Scientists found that pomegranate rind mixed with metal salts was most effective against MRSA, while adding vitamin C helped tackle other common hospital infections.

But – and there are at least a couple of big ‘buts’ here… How well does this concoction compare to other currently available drugs (like vancomycin) that are still effective against most strains of MRSA (or of P.aeruginosa)? The story doesn’t tell us; the way it reads, the study looked at pomegranate rind, alone & variously combined with the other two ingredients. This is borne out by the abstract of the research paper itself, in which the authors conclude that [t]hese results warrant further investigation of PRE as a potential source of new antimicrobial agents. And – we don’t actually know if the pomegranate mixture would have the same antimicrobial effects in humans. Why not? Because these preliminary trials were in vitro ie on bacteria growing on agar in petri dishes. (To be fair, the article does – eventually – get around to pointing this out.) There’s a very long way to go indeed before this one makes it into regular use in hospital care – something the authors of the paper were careful to say, but which the article’s headline, & its first several paragraphs, gloss over.

All this makes me wonder whether a paper by John Ioannidis – published 4 years ago & freely available on-line – ought to be required reading for journalists writing stories about medical ‘breakthroughs’. Writing in PLoS Medicine, Ioannidis makes the point that in the field of medical research, ‘most published research findings are false’. (I need to emphasise here that he is talking about medical research – his essay has been used elsewhere in attemtps to support claims that most research in all fields of science is false, which is not necessarily the case.)

Ioannidis begins by noting that [p]ublished research findings are sometimes refuted by subsequent evidence, with ensuing confusion and disappointment. No surprises here, to anyone working in science; this simply reflects how science operates. Hypotheses are tested, & tested again, & it’s by no means out of the ordinary for an hypothesis to be overturned as a result of this rigorous evaluation. Unfortunately I suspect many non-scientists find this confusing. Having been sold the line that science gives us ‘the truth’; people can’t really be blamed for thinking, well, if scientists were wrong about this, what else are they wrong about? (They can be blamed if they abuse this misunderstanding in others to promote their own particular agenda, however.)

Anyway, Ioannidis goes on to point out that a number of factors can influence the production (& dissemination) of research findings that are false ie not a good reflection of what is actually going on in the biomedical system being studied. One of these is bias: the combination of various design, data, analysis and presentation factors that tend to produce researh findings when they should not be produced. (This can also at times obscure ‘true’ research findings, by the way.) Inefficient use of data, conflicts of interest (potentially a real problem with commercial development of pharmaceutical products), and a failure to notice when findings are statistically significant, can all have an impact on how research findings are presented.

There’s also an unfortunate tendency to trumpet findings by single teams of researchers, viewing their work in isolation at a time when there may be several different teams investigating the same topic. This can be exacerbated by pressure to publish & to get results out there. As Ioannidis says, [w]ith many teams working on the same field and with massive experimental data being produced, timing is of the essence in beating competition. Thus, each team may prioritise on pursuing and disseminating its most impressive ‘positive’ results.  In addition, size of the study (or size of its sample population) is important - studies with only a few patients involved may show a ‘positive’ outcome when in fact the apparent results are due to chance alone (or to some other factor that the design of the study failed to take into consideration).

Required reading? I think so – but I know it’s not likely to happen any time soon. "Gee whiz" & "latest scientific/medical/technological breakthrough" stories are perceived as more attractive to readers, & for whatever reason scientific accuracy seems to take a back seat. Which is a real pity, as it distorts the public view of what science is & how it operates, at a time when more than ever we need people to have at least some understanding of the nature & value of science.

Sigh.

S.W.Gould, M.D.Fielder, A.F.Kelly, W.El Sankary & D.P.Naughton (2009) Antimicrobial pomegranate rind extracts: enhancement by Cu(II) and vitamin C combinations against clinical isolates of Pseudomonas aeruginosa. British Journal of Biomedical Science 66(3): 129-132

J.P.A.Ioannidis (2005) Why most published research findings are false. PLos Medicine 2(8): e124. doi: 10.1371/journal.pmed.0020124

 

australian red beech Alison Campbell Dec 27

No Comments

We saw this lovely tree on the shoreline at Cape Tribulation. The flowers last just a day before their petals fall. I took this particular photo because I liked the way the fallen petals exposed the colourful reproductive structures – I’m always on the lookout for images to use in my lectures.

red beech flower.JPG

This reminds me that Charles Darwin’s grandfather, Erasmus, wrote a long poem about plants which talked about their reproductive features in what was probably regarded as fairly salacious in its time. Take this verse, for example (the words in capitals are genus names):

"With vain desires the pensive ALCEA burns/And, like sad ELOISA, loves and mourns./The freckled IRIS owns a fiercer flame,/And three unjealous husbands wed the dame./CUPRESSUS dark disdains his dusky bride,/One dome contains them, but two beds divide."

Erasmus’ metaphors makeit sound as if he’s talking about all sorts of hanky-panky – but under it all he’s talking about the arrangement of stamens & carpels & how their number & arrangement relates to plant taxonomy a la Linnaeus. I fear my lectures are quite staid by comparison!

what researchers really mean Alison Campbell Dec 26

No Comments

Researcher Translation

From xkcd – & thanks to Orac where I saw it first.

I wouldn’t mind a hovercar…guess I’m not in the right area  :-)

may your christmas be filled… Alison Campbell Dec 25

No Comments

… with good things:

wonderful company

pleasant surprises

and good food

but perhaps not too much of that last one – you don’t want to end up like Winston:

 

 

 too much catmas.jpg

 

botanical architecture Alison Campbell Dec 22

No Comments

Plant roots don’t just grow down under the soil surface. A few posts back I wrote about the aerial roots of strangler figs: beginning as thin hair-like structures, they thicken into strong cables & eventually their interlaced networks engult the trunk of the hapless host tree. Then there are the pneumatophores of mangroves and bald cypresses, their pores & air-filled internal spaces allowing the tree roots to obtain oxygen directly from the air (an adaptation to life in anoxic soils). And of course, there are buttress roots.

If you’re familiar with NZ trees, you may have seen pukatea, with its ‘plank buttresses’: thin flap-like extensions that rise up from the roots & extend up the base of the stem. We saw very similar buttress roots in the Daintree rainforests:

Alison & buttress roots.JPG

You can see from this picture how high these buttresses rise above the ground – there’s one behind me & others to the right of the image. (According to wikipedia they can be nearly 5m high in some specimens, so my tree is just a tiddler really!) Many tropical trees have similar structures: they’re most commonly seen in swamp-growing plants. In mature trees these roots may be asymmetrically distributed around the trunk & longer on the side facing into the prevailing wind (those on the leeward side tend to be taller). That would be an interesting subject for a field study!! You’ll see similar structures in gothic cathedrals – the following photo shows the soaring arch of a flying buttress on Notre Dame cathedral in Paris. These elegant structures help to support the weight of imposing mediaeval buildings, allowing architects to build higher while decreasing the odds of a catastropic collapse as the building’s mass increased.

Notre Dame flying butresses.jpgThe usual view of buttress roots is that they function in the same way, providing additional support for the tree – something which would be particularly useful in the sodden soils of swamps. I’ve heard it said that the buttress roots of plants inspired medieval architects to design their own soaring supprt arches. (But then, most buttress-forming trees go in the tropics, & few mediaeval architects would have made it so far south… Perhaps this tale of life imitating art is a case of a nice just-so story?) Anyway, reading about the Daintree after our visit, I saw the suggestion that the roots don’t act in this way (& – anecdotally! – our guide, Ross, commented that he often saw fallen trees whose buttress roots had not supported them particularly well). Instead, the guide book said, the curving flanges of the roots channel nutrients into the area around the tree, preventing valuable minerals and other materials from being washed away in heavy rain. You can see those curving structures here:

buttress roots.JPGSo which is the more likely explanation? A 1999 paper examined the function of these specialised roots, comparing how effective buttressed & non-buttressed roots were at anchoring tropical trees (Crook, Ennos & Banks, 1999). These authors commented that buttress roots had ‘sinker’ roots extending downwards into the soil from the ends of the buttresses, something that ‘non-buttress’ trees didn’t have (although both types of tree had tap roots). In anchorage tests, where the trees were subjected to lateral forces, the buttressed trees performed much better, being considerably less likely to be overthrown. (My engineering colleagues would say that the buttress roots function as ‘tension & compression members’.) So that strongly supports the ‘usual’ view.

But the idea that explanation might be ‘better’ than another could well be a false dichotomy: the roots could well serve both functions. (As my friend Rose has said, we do tend to go for single, simple, reductionist explanations, and this is a pity because it can divert us from the beauty of a fuller, more complex situation.) Rainforest soils are often thin & surprisingly low in nutrients: forest trees put out shallow, lateral ‘feeder’ roots to garner as many nutrients as possible. As that last photo shows, curving buttress roots hold fallen leaves & other debris close to the tree. It had rained heavily the night before we went into the forest & you could see in places how materials had washed down & become trapped in the network of above-surface roots, which would surely tend to maximise the plant’s ability to obtain the nutrients it needs.

One structure, at least two functions, both advantageous to the tree & so likely to have been strongly selected for. The simplest, single explanation may not always be the full story :-)

M.J.Crook, A.R.Ennos & R.Banks (1999) The function of buttress roots: a comparative study of the anchorage systems of buttressed (Aglaia and Nephelium ramboutan species) and non-buttressed (Mallotus wrayi) tropical trees. Journal of Experimental Botany 48(9):1703-1716

 

 

cassowaries: crucial to rainforest ecology Alison Campbell Dec 21

No Comments

This is the only photo we got of a cassowary, on our recent jaunt to Australia. (I’ll stop rubbing it in soon, I promise!). She was sitting in the corner of an enclosure at the Habitat in Port Douglas.

female cassowary.JPG

Like our own kiwi, cassowaries belong to the ancient flightless group of birds known as ratites. Cassowaries are rainforest birds, & in Australia as the rainforests shrank so did the cassowary population, so that now there are only about 1500 left in the wild, 150 of them in the Daintree National Park (DNA data from the birds’ dung was used to gain an accurate estimate of population size). And this poses a problem for the forest, because the cassowaries play a crucial role in distributing the seeds of many of the trees.

During our trip to the Daintree we visited Noah Creek, where our guide told us there are 3 resident cassowaries: one large female and 2 smaller males. (Like our own moa, cassowaries are sexually dimorphic in body size.) He described taking one party through & meeting one of the males on a track: the male had his chicks with him & casually sauntered down the path, whle Ross & his clients stood stock-still & watched (probably with equal parts of wonder & fear – cassowaries have a reputation for aggression & can do a lot of damage if aroused. However, a 1999 review found that most cassowary attacks on humans were by birds that had previously been fed by people. It seems that feeding changes their natural behaviour so that they lose their fear of people, becoming bold & confident. That same review found only 1 death from 221 attacks – & the deceased individual had tried to kill the bird in the first place!). We weren’t so lucky, but we did see signs of the birds’ foraging & he showed us some of the things they eat, including the cassowary plum:

cassowary plum fruit.JPG

This sky-blue fruit is about 5-6cm long. Its pale blue skin covers only a thin layer of flesh; much of the inside of the cassowary plum is taken up by a large, fibrous-skinned fruit, and the whole thing is far too large for most birds to swallow. Which is where the cassowary comes in. It swallows the fruits whole &, after a fairly fast passage through the bird’s gut, the seeds are egested in its large faeces ie with a nice side order of fertiliser to get them started. In fact, it seems that the seeds are more likely to germinate when they’ve passed through a cassowary, than when they haven’t.

In fact, your typical dollop of cassowary dung contains a lot of large seeds (not my photo – it’s from bunyipco):

[dung.jpg]

You can probably see where this is going. Although other animals also eat the rainforest plants’ fruit & distribute their seeds (eg the white-tailed rat is the only other animal to eat cassowary plums, presumably because it too has evolved ways of dealing with the toxic alkaloids the fruit contains), cassowaries are probably the most significant agent of seed dispersal. They eat the fruits of around 150 different species of plant, & it’s estimated that around half of these plants are entirely dependent on these big birds to disperse their seeds. But cassowaries face a number of threats to their existence – habitat fragmentation and loss, vehicles, dogs & feral pigs, & disease. If they should disappear, their loss would probably have significant effects on the ecology of the rainforest. In other words, cassowaries are a keystone species – take them away & the whole ecosystem may change irrevocably. Not a happy thought.

great balls of sand Alison Campbell Dec 20

No Comments

We went for quite a few walks on the beach while we were in Port Douglas, usually in the early morning before things got too hot! We were surprised by the near-total lack of shells washed up on the sand (the copious cuttle-fish ‘bones’ didnt’ count). And fascinated by the way that the sand between high & mid-tide was usually covered by little balls of sand.

mud snail mud balls.JPG

On closer inspection we could see that among the soft sandy beads were holes dug down into the substrate:

Cow Beach, crab holes.JPG

When we first saw all this, we thought we were looking at the wastes expelled by buried shellfish, but when we watched carefully we saw that it was all produced by well-camouflaged, sand-coloured crabs, scurrying around among the sand balls and diving down into the holes at the first sign of danger. Some of those holes were quite large; neither of us was game to put a finger down to seek for an inhabitant.

big crab hole & balls.JPG

And while there were definitely crabs of many sizes living in the intertidal zone, we suspected that there could also be crabs of more than one species. Some of the sand balls were quite poorly formed while others were very precisely rolled, and they also differed in how they were arranged around the hole. In some cases they were arranged into neat circular walls, while other crabs seemed to hurl their balls out any old how. You can see why we found them so fascinating. (The locals probably thought to themselves, ‘crazy Kiwi tourists, spending so much time noses down & bums up on the beach!’)

A quick google found out that this behaviour is common in fiddler crabs. These little animals are detritiovores, bringing gobs of sediment to their mouths & sifting through this to find anything edible, The left-over sand or mud is formed into balls & deposited around the entrance to the crabs’ home burrows. But we weren’t seeing fiddler crabs, because ‘our’ crabs had symmetrical pincers (in fiddler crabs one of the front claws is much enlarged, & used to signal to the neighbours, marking territories & attracting mates.). ‘Our’ crabs turned out to be ghost crabs, & our suspicion was correct – there is more than one species living on Port Douglas’s Four Mile Beach.

As for the differences in sand-ball construction & distribution patterns, in some species at least this may be related to courtship & territory displays. (It would be safe to describe the various walls & heaps & scatterings of sand as a visual display.) I couldn’t find a lot of easily accessible material on ghost crabs. But there’s some experimental data on fiddler crab ball-building - & some questions to get you thinking about how to interpret this – at this site by the Association for the Study of Animal Behaviour. It certainly looks as though female fiddler crabs find big piles of balls extremely attractive :-)

a whale of a community Alison Campbell Dec 19

No Comments

 ’Community’ is one of those words that has different meanings in science & general use. Every time I set an essay that asks students to talk about biological communities, someone will tell me about ant communities, or monkey communities, or human communities. But a biological community is a group of populations from several different species, living & interacting in a particular area.

There are at least two schools of thought when it comes to considering the nature of a biological community. One is that the various species that make up a community have evolved together, & that a particular type of community will always have the same general makeup & structure. Another is what you could call an ‘individualistic’ model: members of any given community come together by chance. I was moved to write about this when I came across a website detailing the weird & wonderful members of a community based upon the decaying carcase of a dead sperm whale that lies 2900m below the surface of the ocean – surely one from the ‘individualistic’ end of the spectrum, as the community could form only when the whale’s corpse arrived at the bottom of the sea, & there’s surely no way of predicting when & where that might happen. (With the proviso, of course, that many colonisers may well arrive in larval form, dispersed widely throughout the water column, so there will be some species in common.) The particular community that’s the focus here includes hagfish**, snails, crabs, fish, crabs, sea anemones, octopuses - & of course, bone-eating worms!

Find another deceased & sunken whale, & you will almost certainly find a different assemblage of species. Ah, the wonders of the deep-ocean decomposition/recycling system! :-)

** Hagfish have neither jaws nor a bony skeleton, and the cartilagenous supporting rod called a notochord is retained throughout their life. They’re scavengers & produce large quantities of slime when handled, a characteristic that has seen them also dubbed ‘snot eels’. (‘Rock snot’ aka Didymo, snot eels, bone-eating snot-flowers – did those naming these various species have something of a preoccupation with nasal exudates??)

preparing for the future Alison Campbell Dec 17

No Comments

Just catching up on my ‘official’ reading, including the Education Review. The November 13th issue (see? I said I was behind!) included a series of articles to do with the government’s draft Tertiary Education Strategy (or TES for short). One in particular caught my eye as it was related to something I wrote a while ago, on choosing school subjects carefully so that they support your future study plans. (Yes, it’s that time of year again – we are frantically busy in the Dean’s office working on students’ applications to enrol for 2010.)

The New Zealand Vice-Chancellors’ Committee (NZVCC) indicated more could be done at secondary schools to realise at least two of the goals of the TES. It said subject choices and performance at secondary school were among the barriers preventing more young people and more Maori and Pasifika people from gaining degrees.

"… a particular block toyoung people advancing successfully from secondary to degree level study s the lack of continuity between secondary school and university. Students need advice from year 9 onwards to prepare them to go on to university study, particularly about appropriate subject choices."

I’m not going to open the ‘performance’ can of worms; there are so many factors that can affect how well a particular student performs, and at least some of them are outside the reach of the school. But subject choices – well, let me start by saying that yesterday I had to decline someone who wanted to enrol in the Bachelor of Engineering on the grounds that they hadn’t taken maths or physics in their senior years at high school… It really is so very important to think carefully about your future career options and aspirations, & make sure that the subjects you study at school will support those intentions.

Of course this applies to all students, whatever career they intend to enter on leaving school. I know perfectly well that not all those in year 13 will be coming on to university study (& perhaps NZVCC could have recognised that in their statement). But you still need to start planning ahead, so that you don’t close any options off too early.

And I want to say up front that any ‘lack of continuity’ cuts both ways. University lecturers need to be aware of school curricula in their particular subjects, & to structure their first-year courses so as to bridge students in to university learning. As a secondary-turned-tertiary teacher,  I know all too well that there can be some quite significant gaps between students’ prior learning at school and what tertiary teachers assume their ‘new entrant’ students to know (& this personal anecdote is strongly supported by the findings of a PhD thesis that I supervised),

Because of the wide range of students’ future career aspirations, universities can’t expect that schools will focus solely on preparing their senior students for university study. There are so many differences – not just in the curriculum – between the final year of high school & the first year of university, & I believe those of us responsible for first-year teaching have a responsibility to assist students in making the transition between the two. This is spelled out by the Australian Learning & Teaching Council:

The curriculum and its delivery should be designed to be consistent and explicit in assisting students’ transition from their previous educational experience to the nature of learning in higher education and learning in their discipline as part of their lifelong learning. The first -year curriculum should be designed to mediate and support transition as a process that occurs over time. In this way, the first-year curriculum will enable successful student transition into first year, through first year, into later years and ultimately out into the world of work, professional practice and career attainment.

And this would be a win-win outcome for all concerned.

owlcat. definitely not coming to a place near you, any time soon Alison Campbell Dec 15

No Comments

Owlcat:

owlcat - why evolution is so interesting.jpg

Makes me chuckle when I think about it. Not just because Lolcats make me LOL (they do), but also because the idea of an owlcat epitomises a standard creationist argument. It goes something like this: if evolution is true, how come there aren’t any crocoducks/owlcats/<insert laughable hybrid here>?

This is an example of the ‘straw man’ argument. No evolutionary biologist would suggest – except in jest – the concept of a crocoduck, or an owlcat (no matter how sweet this hypothetical beast might look). This is because ducks & crocodiles, cats & owls, are all modern species, far removed from any last common ancestor.

(In the case of owls & cats, very far removed indeed; mammals & reptiles (including birds) last shared a common ancestor around 300 million years ago, & have followed divergent evolutionary paths since then. Birds appeared on the scene much more recently, evolving from a group of dinosaurs known as maniraptors during the Jurassic period.- and (contrary to what this straw-man claim implies) there is a rather nice series of transitional fossils that lets us trace the ancestry of this clade.)

Thus true transitional fossils will not look like some fusion of their modern descendants – there is too much time & too many gradual transitions between them. As Richard Dawkins puts it:

The demand for a crocoduck is based on the misunderstanding that there should be intermediates between modern animals and other modern animals.

Unfortunately (for the creationist camp) this isn’t how it works. Dawkins again (using leopards & rabbits as his pair of modern species):

You start with any modern animal you like, such as a rabbit, and put her next to her mother and then her mother in a chain that goes back in time a very long way until you hit the common ancestor with some other animal such as a leopard. It would no longer look like a rabbit but more like a shrew.

You call that the hairpin bend and you turn round and start going forward in time. You just keep taking the fork that leads to the leopard and in time you’ll get to the modern animal.

So, while owlcats are cute, & crocoducks giggle-making, any request that evolutionary biology should produce an actual animal simply betrays a profound misunderstanding of how evolution operates.

Network-wide options by YD - Freelance Wordpress Developer