"The form, then, of any portion of matter, whether it be living or dead, and the changes of form which are apparent in its movements and in its growth, may in all cases alike be described as due to the actions of force. In short, the form of an object is a 'diagram' of forces..."

-D'Arcy Thompson

Course Theme

This course is about the form of organisms and how organs and body parts behave.  It deals with size, symmetry, shape, texture, colour, topography, materials etc.: with all structural features of the bodies of plants and animals.  The course is part comparative biomechanics, part physiology, part morphology.  We ask especially how forces are translocated and how body parts work to achieve mobility.  The aim is to examine organisms and hypothesize the history revealed in their morphology.

Analysis of what an organ does has a nested complexity.  It is simple to say ‘a bird’s wing functions in flight’.  But the detail of form and behaviour of flying is really quite complex, with layers of related adaptation.  The mechanism of flight involves underlying physics -- air flow generating lift and drag -- and it also involves adaptations of bone and muscle, feather barbules, air sacs and lungs.  Structural flight adaptations differ for different bird species: they are not the same in an albatross that soars, an ostrich that runs, or in a hummingbird hovering to draw nectar.  Comparison of flight adaptations in multiple taxa is part of our approach.

'Why' is an evolutionary or historical question and this course is also about the history of organs: why have structures evolved to develop with certain features of shape, size, stiffness, elasticity, colour, etc.  Why have these features come to exist in certain taxa while other features are lacking?  Organism body parts are largely the product of selection in particular ecological contexts.  Inherited body-part forms vary and individuals are selected in different habitats because their morphology allows them to be more fit.

The computer age has given us unparalleled virtual exposure to organisms and so yes, there are lots of web-sourced animal and plant pictures in this course; but real experience is still always to be preferred over a picture.  It is better to actually wander through a dark rainforest, dive on a coral reef or wade in a spruce bog, than to experience these habitats and their organisms in a movie.  So labs are important because they are real rather than virtual.  In the lab we study and dissect the real body part.  (A better lab would of course be a walk in a rainforest.)  The 10 or so labs, somewhat independently of the lectures, tour major body systems: integument and skeletal [locomotion], digestive, circulatory,nervous, reproductive, excretory etc.

To describe structures we use pictures, words and also drawings.  Why draw where it is so easy to take a picture?  Because drawing is a technique in its own right, a study method that pushes one toward insight.  By trying to capture shape manually you come to understand how it might transmit force.  Drawings properly done are filters: they filter out the unimportant and filter in the relevant – they illustrate just the relevant features.  Drawing (scientific drawing) is a significant component of the labs in Bio 325.

Imagine it as isn't: in arriving at hypotheses of structural adaptation it is a useful thing to visualize a structure in a form other than the way it now appears.  Imagine a different shape or stiffness, then ask how the structure might work in this alternative form.  Would the altered shape promote survival in the animal or create problems?  For example: beetles have two wing pairs, one on the middle segment of their thorax, one on the next segment rearward, the metathorax.  The anterior wing pair is very different from the posterior: they are of thick strong cuticle and relatively less flexible.  The metathoracic wings are thin, semi-transparent elastic membranes, with a pattern of flexible veins.  How might these two sorts of wings work if one pair had the features of the other?  Would the beetle fly as well?  What would happen to a beetle living with membranous forewings?  In the process of thinking about this imagined change, the likely adaptive roles of these structures become clearer  -- but you do need to know something about how beetles live.

You will need a mental filing system for the diverse taxa encountered in lecture examples.  So learn more than you now know about the major animal phyla and their diagnostic features.  You should know the common families of plants.  I will mention these larger taxa in passing but it is good to have access to an introductory biology text (or to consult the web).

The history of animals and plants is written on their bodies for those who will read.

Marking Scheme

Midterm test (in lecture Oct. 6) . . . . . . . . . . 10%
Labwork (drawings, quizzes) first half. . . . . .5%
Labwork Bellringer first half . . . . . . . . . . . . 10%
Labwork (drawings, quizzes) second half. . . 5%
Labwork Bellringer overall . . . . . . . . . . . . . 20%
Final Exam . . . . . . . . . . . . . . . . . . . . . . . . . 50%