BE/BIO 105: Introduction to Biomechanics

Monday, Wednesday, Friday, 2:00-3:00, 102 Steele

Instructor: Michael Dickinson flyman@caltech.edu Teaching Assistants: Peter Wier: weir@caltech.edu Sawyer Fuller: minster@caltech.edu Text: Comparative Biomechanics: Life’s Physical World Steven Vogel, Princeton, 1st Edition

Schedule:Lectures – M W F (2-3pm)

Monday & Wednesdays – standard lectures Friday – lecture & discussion on assigned reading (required)

Office Hours (MD)– Wednesdays (3-5pm) 207 Keck

Grading: There will be 2 take home exams (33% each) and homework (33%)

Grading policy: Homework will be handed out (and posted) in class on Friday. Homework is due by 5pm the following Wed. (deposit box outside Keck 207). Each day an assignment is late results in a 10% reduction in score (compounded daily).For take home exams, the daily reduction rate is 20%. For these purposes, each day is defined from 5pm to 5pm. Please take note, Keck Hall is locked at 5pm each day.

Gwyneth Card

flight initiation

voluntary

escape

Integrative Approach

central nervous system

musculoskeletal system

motorcommands

dynamics& environment

kinematics & forces

Behavior

sensory systems

sensory feedback

olfaction

mechano-sensory

vision

Comparative Biomechanics:The application of physics and engineering to study principles of organismal design

A short history of biomechanics

Part 1. The Greeks

Socrates469-399 b.c.

Good points: fostered interestin natural world.

Bad points: liked hemlock drinks

Plato427-347 b.c.

Good points:liked math

Bad points:hated experiments

Aristotle384-322 b.c.

Good points:liked experiments

Bad points:hated math

Wrote: De Motu Animalium

Part 2. The Romans

Galen129-200 AD

Physician to one of the 5 ‘good’ emperors, Marcus Aurelius

Good points: initiated use of ‘animal models’ in physiologyand medicine.

Bad points: Promoted wacky Hippocratian notions, e.g. four body humours (blood, yellow bile, black bile and phlegm)

Influence lasted until Renaissance.As important in eastern Islamic culture as western Christian culture

Part 3. The Italians

Leonardo da Vinci1452-1519

Good points: genius

Bad points: paranoid genius

Direct combination of engineering and biology

‘Bio-inspired’ engineering

Galileo Galilei1564 -1642

Good points: great scientist

Bad points: terrible politician

Modern concepts of staticforces and scale.

Consider ‘simple’animal/plant:

Mass xgravity

strength~ sectional area

Length = LMass ~L3

Strength ~L2

Force/Area scales with L.

big things need thickLegs.

Principle of Similitude

Giovanni Borelli 1608-1679

Good points: father ofbiomechanics

Bad points: grimaced a lot

Conceived musculo-skeletal system ascollections of levers and gears:

e.g. ‘Borelli’s Law’work to jump ~ mass x height;therefore, height ~ work/mass.muscle work ~ muscle mass,therefore height is independent of size!

Carl Culmann Hermann von Meyer1821-1881 1801-169

Good points:Collaborative team of engineer and paleontologist

Bad points:facial hair style

Part 4. The Germans

Stress lines in crane and femur

Part 5. Other People

Darcy Thompson 1860-1948

Good points:•Father of developmental mechanics.•Considered by many to be greatest scientific writer in English language•Wrote On Growth and Form

Sydnie Manton 1903-1979

Good points:•Combined study of phylogeny with biomechanics•Anticipated synthesis of evolution and development

Edward Muybridge 1830-1904

Good points:•Figured out horse gallop•Anticipated importance of high speed cine/video

•Bad points: Hung out at Stanford

Steven Vogel

Steven Wainwright

Lecture #2: StuffBE/Bio 105

Central question: how do things work?

Why is oak tree shaped like this? Why is alder shaped like this?

What is role of leafmorphology?

Why do/don’t trees fall down?