Anatomical directions (land vertebrates)

 Another of my old articles from my previous website. This one is about the names of the basic anatomical directions. Albeit confusing at first, this jargon is actually pretty useful once you get the hang of it! 

(I introduced the topic with a silly short poem...)

Right is wrong. 

It should be left. 

Left right there. 

Hehe, no, seriously...

There are four main contrasting pairs of terms of directions in anatomy. Note that these apply mainly to tetrapods, or four-limbed vertebrates, to which dinosaurs do belong, but many animals such as molluscs, insects and spiders do not. However, since this site is about dinosaurs, these are the most relevant ones. 

These terms rely on the fact that tetrapods have a distinct head, trunk and tail, four limbs, and clear up and down sides. 

Dorsal means toward and beyond the animal’s back, and ventral means toward and beyond the animal’s belly. Note, however, that most tetrapods have their trunk lying horizontally, unlike in humans (and kangaroos!), meaning that their back faces upward, and their belly downward. Therefore, dorsal and ventral may loosely refer to up and down. So, the ribs would be located ventrally to the spinal column. We could apply this to the skull too, for example by saying that the upper jaw is dorsal to the lower jaw, or that the tooth sockets lie ventrally to the eye sockets. Moreover, stegosaurs are characterised by large plates on their backs, which we could call dorsal plates (in this case, maybe the word dorsal refers more to the fact that the plates sit on the actual back of the animal, but they are nevertheless the most dorsal part of the stegosaur).  

Anterior refers to structures toward the tip of the snout, while posterior is used for things toward the tip of the tail. In simple terms, this means forward and backward, since most tetrapods have their snout facing forward, and so on. Thus, the forelimbs are located anteriorly to the hindlimbs, and the hip region lies posteriorly to the rib cage. Ceratopsians, including Triceratops, have a special beak-like bone (called the rostral bone) attached anteriorly to their upper jaw. Stegosaurs had formidable spikes on the posterior end of their tails. 

Proximal and distal apply chiefly to the limbs (and sometimes to the tail). Proximal means closer to the trunk, while distal means further away from the trunk. Thus, the fingertips are the distal ends of the forelimb, and the femur (thigh bone) is proximal to the knee cap. Many theropods had the distal end of their pubis (a bone in the hip region facing ventrally, or downward) formed like a boot.

Tetrapods, like many other animals, have a clear midline that separates the body from top to bottom into two identical but mirror-imaged halves (the line of symmetry). Referring to this so-called sagittal plane, we use the terms lateral, meaning away from the midline, and medial, meaning toward the middle. The shoulders are generally lateral to the skull, while the tail would be medial to the shoulders. Some nodosaurs (a type of ankylosaur), eg. Edmontonia, had enormous spikes extending forward and laterally from their shoulders. 

These terms can of course be combined. The two subgroups within Dinosauria, Saurischia and Ornithischia, are usually distinguished by the former having the pubis facing anterioventrally (i.e. forward and downward) and the latter having it oriented posterioventrally (i.e. backward and downward). The characteristic neck frill of the ceratopsians can be said to be facing posteriodorsally (backward and upward), while it is also expanded laterally (broadened). In addition, one can refer to structures running along a bone or an axis: theropod teeth had serrations running proximodistally along the edge – that is, they extend from the proximal to the distal part of the tooth. 

How would you describe the direction of Edmontonia's shoulder spikes, using the combined formal terms? 

This system is rather useful, being fundamentally simple (although the words may be confusing if you are not used to them) and concise, and understanding these will surely help you understand more formal texts, especially descriptions. Trust me: once you get the hang of it, you will find it very convenient! 

Making better world members – the IB learner profile

On Boxing day and close to a new year, I think a little self-reflective post is in order. The end of a year is always a good time to enjoy what has passed, and dream of what is to come, and I feel it is a shame that I never really take the time to think enough about what has changed – around and within me – in the year. We should all give a few moments to think back on what we have achieved, what we have gained, and what we have lost.

Now that I have (two) blog(s), I have a good excuse to sit down and do this thoroughly and share it with anyone who might feel the same, or different – likewise, I urge you all to do the same! The best way to search your soul could be to tell others about yourself, explain your thoughts, describe your history, and illustrate your dreams.

In this post, I will not torture you by going through all or most of my calm, not very eventful life. I only want to focus on a single thing: my development as person in this world. So, this will be both about how the way I view the world has changed, and how this new perception has influenced me as a person.

The University of Bristol (where I began to study this semester) has a barely noticeable tab on its student webpage that encourages students to pursue what they call a Personal Development Plan (PDP), which aims to – through rigorous reflection and self-evaluation – evoke the student’s strengths and weaknesses and to produce a plan to help the student promote his/her talents and work on his/her shortcomings. This all sounds very good, but the whole purpose of it, they say, is to enhance the student’s employability – to make one more attractive on the job market.

I wouldn’t object to that! But, I have had a hard time motivating myself to go through all that paperwork to tick squares, rate my confidence in a set of skills from one to five, make up some sort of plan of how to improve a prioritised bunch of my weaknesses. I have never been much for reflection, I admit, and this system is not helping at all.

Dinosaur discussion or essay topics: examples

This is another of my articles from the abandoned webpage, one that sought to inspire young students to explore the wealth of unanswered questions on the subject of dinosaurs.

Here follows a couple of examples of topics for discussion, for fun, or for a school essay, if you like. But, first I wish to distinguish between different ways of analysing a topic (I focus on analysis, since topics for mere description should not be hard to find, in addition to the fact that texts that only describe rarely make good essays, and it is impossible to build a debate on descriptions). To discuss means both to give a detailed account of an issue, but also to consider more than one perspective. Consequently, a topic for discussion must be a topic where there are, or could be, several different, sometimes completely opposite points of view. Moreover, as in any debate or essay, you wish to reach some form of conclusion, so it is essential to actually compare and evaluate the different perspectives, rather than just stating them. To compare and contrast strictly means only to describe (or maybe discuss) similarities and differences, but usually implies assessment of their importance and/or implications (implication in this sense refers to the results or effects of an argument, discovery or revelation). To evaluate is to assess something, usually an argument, a piece of evidence, or a model. When you evaluate, you usually point out strengths and weaknesses, and weigh them against each other to reach a conclusion to whether the argument or evidence is strong or weak overall.

As you might notice, the distinctions between these forms of analysis are very fine: a discussion does not exclude comparison or evaluation, and evaluation is in essence a comparison. However, it can be worth its weight in gold to be clear about what these terms imply. If you are asked to write a comparative essay, you are not expected to evaluate evidence; you would probably not loose points for doing so, but you might well be wasting precious time. Knowing exactly what kind of answer is expected is, of course, even more crucial for exam writing, where you are under considerable time pressure and need to give precise answers. Moreover, not answering the demands of a question does not impress the examiner, while giving a strictly focused answer shows that you know what you are doing.

Let us move on to the more fun part: the topics. In some cases, I provide brief examples both to show why this is a topic worth looking into, and to aid you in your search for more information. The idea is for you to dig deeper on your own, and discover the myriad of different views and explanations, and to realise why this is or was a topic of controversy.  

How/why did the dinosaurs grow so enormous? Here, you can discuss advantages and disadvantages of having a large body, and evaluate which you believe would have been the main advantage(s). (Given that the dinosaurs did grow enormous suggests that the advantages did outweigh the problems.) There are several examples of advantages, including invulnerability from smaller animals, lower rate of heat loss (larger bodies give off heat much slower, so it is easier to keep warm), and the ability to travel farther. Some disadvantages would be restricted movement (especially in places like a dense forest; this is why most large dinosaurs lived in the open plains), higher food requirements, and several physiological constraints. Moreover, you could spice your discussion with an investigation into why some dinosaurs did not grow so large; a handful of dinosaurs weighed less than a kilo (e.g. Compsognathus, Archaeopteryx, Sinosauropteryx), and a great deal of theropods and some ornithopods weighed under a tonne (e.g. the dromaeosaurids, or “raptors”, ornithomimids, most oviraptorids, and the hypsilophodontids). Understanding why these preferred a more modest size may shed some light on why other dinosaurs favoured gigantism instead.

Last day

Yesterday was the last day of term. Most of us have gone home, though I will stay over the weekend (the flights were cheaper on Monday!) and finish off some studying. Of course, I felt really sad about leaving this place and these wonderful people, but we all had happy goobyes, and I come closer and closer to fully realise I will see my family and friends again when I go back to Sweden! (I have known that for a loooong time, but as usual with me, it takes time for it so sink in and for me to really realise it... Sounds a bit daft, I know! hahaha!!)

So what I will be up to these two days before departing is basically packing and studying. We have so-called Progress Exams in January. I thought I would write a short post on study tactics – how to think about and organise your studies so that you cover both as much width and depth as possible with hopefully minimal effort. I give these tips to anyone who might be in a similar situation and in need of some ideas of how to make the most of one's time.

Our Progress Exams are all multiple choice questions, which means that we are given about five or more alternative answers to each question and must choose the correct one to receive the mark (one per question). Usually, some of the questions are really tricky, where the several alternatives makes you more unsure of what to think, and may thus sometimes be harder than clear short-answer questions. Multiple choice questions are meant to test understanding of main concepts and factual knowledge. The questions may be considerably specific on a narrow topic; rarely, they address major concepts – you are expected to be able to use your understanding of the subject to figure the more detailed problems out!

I love multiple choice questions! They are generally easy and fun; I enjoy in particular the trick questions. The norm is to be given at least one minute of time per question (we have fifty questions in an hour), so answering the 'easy' ones quickly gives you more time on the harder problems. This sounds obvious, but evoking that thought gives you a clue on how to study for multiple choice questions: (1) make sure you really understand all major concepts; (2) revise details. If the 'way of thinking' of the subject is your second nature, and if you have an additional set of detailed facts fresh in your head, you should be able to complete the examination smoothly and painlessly!

Our exams at the end of the year, however, will be both multiple choice questions and essay questions. The essay part will consist of several long-answer questions, out of which we will choose a given number and answer in essay form.

Preparing for essay questions is quite different from for multiple choice questions: indeed, the need to understand all major features and terms is essential, as are details – they make your essay more impressive. However, essay answers demand substantially more indepth and exhaustive knowledge on a subject. You definitely need broadth of knowledge, since you do not know what subtopics the given questions will relate to, so if you study only a few topics, there is a great risk of not having enough questions that you can answer! However, to make a really good essay, you also need deep and detailed knowledge. The more you have to say about the subject the better, and the more precise and appropriate your examples are, the more you will show that you know what you are doing.

How could I do this without going to too much trouble, then? My suggestion is to think about what topics to spciallise in! Assess each topic on (a) how much you have to say about it/how interested you are in learning more about it; (b) how likely it is that there will be a question on it; (c) how many other topics this one may relate to. The first point determines the depth, the second tells you how useful it could be to speciallise in this topic, and the third determines the broadth of questions you may be able to answer from that single topic. This is how you can minimise effort: by making sure you pick topics there is indepth knowledge easily available, by making sure you enjoy the work, by not reading (much) on topics that are unlikely to be of use, and finally by choosing topics that may relate to several larger areas and/or specific examples that can be used for many different topics.

To give an example, one of our biology courses, Diversity of Life, covers evolutionary theory, and the evolution and classification of unicellular organisms, land plants, fungi and most types of animals. It is highly likely that at least one question will be on evolution, since it is such a debatable area. Thus, to prepare for a question on evolution, I will look for and learn examples from as many of the different types of organisms we are taught about, and relate those to ideas on evolutionary theory. These examples will also prove helpful when discussing questions regarding these organism groups only, and I will make sure that is extract examples that relate to as many different possible questions there could be on the exams.

I hope these tips can ease some study pain for you, and wish you all a merry christmas, and a weird and wonderful new year!!

When life gives you lemons...

... make lemonade!

Sharing a small refrigerator with a bunch of careless students who prop it full of their food, and leave dripping liquids and open packages of sandwich spread (they don't even have the sense of putting a plastic bag around it) can be hellish when it gets to the extreme.

Luckily, it has not been awfully bad in our frigde yet, but I am still reluctant to keep my lunch food stored in it. Another funny thing is that the heater in our room does not work. We keep it warm solely by floor heating – which is not ideal, since the English heating systems seems to work in bursts of extreme warming and periods of rest for the temperature to cool down, instead of maintaining an even temperature...

... Anyway, my point is: if our room is freezing, why bother putting my food in that horrendous fridge? I just leave some of the stuff on my windowsill! (Although, most of it won't fit there, so it has to go in the fridge.)

Not quite what I meant, but a similar principle, haha...

Image from http://salls-country-life.blogspot.co.uk/2011/08/simple-peachy-pleasure.html

A new blog!!

I just created and designed a new blog! The Bluest Ice will be about current issues related to environment preservation and international development. The blog is still incipient, but I hope to give it a good kick start this week (if my workload permits), so please do check it out any time soon!

I made The Bluest Ice a separate blog in order to keep the topics apart and so avoid confusion – I want this blog to remain centered around paleontology, and The Bluest Ice to be focused on topics related to the problems of today. However, I will probably make cross references between the blogs to keep the viewers of either alert for other potentially intersting texts, and, if any topic overlaps the two, I will of course write a coupled posts for both.

The other reason I decided to create an additional blog was to more effectively promote awareness of various charitable groups and organisations that work toward a better world for us. In this way, I hope to be able to reach out to a wider audience, which is what these types of organisations need. (Thus, I apologise if such inclusions to this paleoblog will cause dustirbance, but please understand I do this with good intentions.)

Ever heard of the MSC? Want to know what it does? Then look out for the coming post on The Bluest Ice!

A note on the taxonomy post!

I just realised when revising plant biology that I forgot to mention that the typical taxon name endings I descrbed in the post on taxonomy rules only apply to animals!! Plant (and probably other organisms) have different conventions for ending names of orders, families, subfamilies, etc. This is because Linnaeus, who engineered the basics of the texonomic system, initially classified all life as either plants or animals (he also tried to classify minerals in a hierachical system...), so he probably intended the different norms of nomenclature to make distinction clearer.

In plants, the order tends to end with -ales and families with -aceae. There may be more conventions, but these are the ones I am aware of.

I apologise and hope my unclearness has not caused any inconvenience!