Differences in Tadpoles – Trying not to get Caught Out by Anthropomorphism

The weekend has brought a number of staff members into the Everything Dinosaur offices, to do the various chores that we have been assigned.  However, we still get plenty of time to sit outside in the sun during our coffee breaks and to observe the many hundreds of tadpoles in the office pond.    As Sir David Attenborough observed in his latest episode of the excellent Radio 4 series “Life Stories”, some animals are easier to distinguish from others of their species.  Humpback whales for example, when they dive, their large, crescent shaped tail flukes often rise clear of the water.  The undersides of these tails are white with black markings.  Each whale has distinct tail markings and when these are photographed they can be used to help identify that individual whale if it is spotted in the future.  From these simple observations scientists have been able to build up a comprehensive picture of the voyages made by individual whales of different species.

Looking for differences in our tadpole population is somewhat more tricky, but not impossible.  Although the animals were hatched within just a few days of each other their variation is remarkable and in only a few minutes, a number of identifying characteristics can be determined.  For example, at first glance the tadpoles all seem to be the same colour, but this is not so, some are darker than others, some are black, some are more a shade of brown.

Not All Tadpoles Are The Same

Frog spawn in the office pond.

Picture credit: Everything Dinosaur

Tadpoles

The tadpoles are all the same species – The Common Frog (Rana temporaria), but even after two weeks differences can be observed in the population.  Identifying individuals without intruding too much (by marking them for example), is complicated by these animal’s rapid growth rate, after all, those that survive will undergo a dramatic metamorphosis in a few weeks.  But certainly, differences between individuals in terms of their size, growth rate, colouration, body length, degree of fluking on the tail can all be made out.

Genetically, all these tadpoles will be slightly different – this is a result of the way in which they were produced – with two parents providing genetic material to the offspring.  Although, we wish to try to avoid being accused of anthropomorphism individuals may have different behaviours.  It might be too much to regard these as different personalities and to label tadpoles as introverts and extroverts as individuals may behave in contrasting ways to others of their kind.  For instance, those tadpoles that are the strongest swimmers have been observed swimming across open stretches of water, perhaps seeking food resources that they can exploit.  Other tadpoles, not as well developed as their siblings remain in the same part of the pond for long periods.  Their growth may be restricted as they are less mobile and therefore less able to find food than some of their counterparts.

Interestingly, mobility in tadpoles residing in our office pond was in previous years we suspect, likely to lead to those tadpoles actively swimming in open water to be predated upon.  There used to be a population of water boatman in the pond.  These aggressive invertebrates would attack and eat any tadpoles that they could catch.  As the water boatman were nektonic (swimming actively in the water column), they were more likely to predate those tadpoles that ventured into open water without cover.  This year, however, we have not observed a single water boatman in the pond.  We suspect that the cold winter killed off our population.  There is now an absence of nektonic predators of tadpoles in the pond. The removal of a predator may enable more tadpoles to metamorphosise and make it to the froglet stage and this environmental change could favour those “bolder” nektonic individuals who venture out into open water.  This subtle change in the predator/prey balance could have an effect on tadpole numbers surviving and influence the type of tadpole “personality” likely to survive into the summer.

We shall continue to observe with fascination.

In the meantime, visit Everything Dinosaur’s website: Everything Dinosaur.

Dinosaur Balloon Art – Not as Easy as it Looks

Weekend took us to my niece’s birthday party (she is four today).  During the fun, festivities and games, the entertainer did some balloon art.  He made swords, teddy bears, giraffes and all sorts of animals for the children.  Not wishing to be left out, one of the Everything Dinosaur team members who attended requested a dinosaur.  Mr Dazzle (the name of the entertainer), explained that he could do dinosaur balloon art, but his repertoire would be slightly limited as he had thirty enthusiastic and very excited four-year olds to manage.

Dinosaur Balloon Art

True to his word, he produced a grey, long-necked dinosaur a few minutes later (see pic).  It certainly had a long neck and legs and it was a very credible effort, not withstanding the fact that it had no tail.

Our Balloon Dinosaur

Picture credit: Everything Dinosaur

Interesting that he choose to depict a sauropod as a grey animal.  As the largest land living animal today (African elephant) is regarded as being grey by many observers, this may have “coloured” our perception as to the colour of the largest type of extinct terrestrial animal – Sauropoda.  The colour of these herbivorous dinosaurs is very much open to speculation, but most illustrators do depict these large animals as coloured grey.  Hatchlings, may have been very differently coloured from adults, perhaps camouflaged to enable them to hide in the undergrowth to avoid predation.  Nice balloon dinosaur though, although a colleague said it reminded them of some of the bizarre Cambrian life forms preserved in the Burgess Shale deposits of British Columbia.

Visit Everything Dinosaur’s award-winning website: Everything Dinosaur.

Brontomerus mcintoshi Research Helps School Pupils Get to Grips with Palaeontology

Pupils at Sacred Heart Primary school, Blackburn, have been travelling back in time to visit the age of Dinosaurs in a range of teaching activities. The budding young palaeontologists in Miss De Piano’s Year Three class, were given the chance to name their very own prehistoric animal.

Students had been getting to grips with fearsome creatures such as Tyrannosaurus rex and Velociraptors as well as marvelling at peaceful plant eating giants such as the armoured Stegosaurus and the huge Diplodocus. This was part of the school’s science week events organised, to coincide with National Science and Engineering Week, by one of the school’s teachers – Mrs Smith. They were given the chance to look at some of the research carried out on a new species of long-necked dinosaur – Brontomerus mcintoshi.  This dinosaur, fossils of which have been found in Utah, (United States), has only just been formally named and scientifically described.

In total, fragmentary remains of two dinosaurs were discovered in the same quarry, one adult and a much smaller juvenile.  The name Brontomerus means “thunder thighs”, in recognition of an enlarged anterior portion of hip-bone associated with the remains of the smaller specimen.  Scientists have suggested that the expanded hip bone served as an anchor for large leg muscles, giving this particular dinosaur very strong legs.

The Age of Dinosaurs

For the young scientists in Miss De Piano’s class the challenge set by Everything Dinosaur was to consider how animals change as they get older.  If animals change as they grow, could they come up with an alternative name for Brontomerus once they had reviewed the fossil evidence?

The class was split into two groups for this part of the dinosaur teaching session, each group was given the task of answering questions on chickens, however, one group was asked to describe a chick, whilst the other portion of the class described an adult bird.  Although each group was asked the same questions, it soon became clear to the pupils that a chick looks very different when compared to an older bird.

Based on this, and with an overview of the fossil evidence of Brontomerus provided by Everything Dinosaur, the class set about creating their own names for this type of dinosaur.  All part of the fun when it comes to teaching about dinosaurs in school.

Organisms Change as they Grow

The 1:35 scale PNSO Torosaurus models (Aubrey and Dabei). The adult Torosaurus figure has an articulated lower jaw. the adult Torosaurus is very different in appearance than the juvenile. Picture credit: Everything Dinosaur.

Picture Credit: Everything Dinosaur

The Torosaurus in the picture (above) is from the PNSO range of prehistoric animal figures.

To view this range: PNSO Age of Dinosaurs Figures.

The chicken was used in this dinosaur workshop to illustrate issues related to ontogeny (how organisms grow), helpful in explaining to the students differences in the fossil skeleton of the adult compared to the juvenile dinosaur.

The pupils worked on the theory that, if this plant-eating dinosaur really had very strong limbs, perhaps it could rear up onto its hind legs to help it to graze on parts of trees that other dinosaurs could not reach, just like a Gerenuk antelope in Africa does today.

A wide variety of alternative names were thought up, a few examples from the clever pupils were Two-legosaurus, Standuposaurus, Treeasaurus, Anteloposaurus and our personal favourite Vegesaurus.
It was a real pleasure visiting Sacred Heart Primary and helping the children with their dinosaur experiments and showing some of our fossils.  Our thanks to all the students, teaching assistants and teachers who helped make the day so special.