Lab 6 8 Today lets do part of

Lab 6 & 8 Today, lets do part of dentition, exercise 8 Then Exam 1 prep

Evidence from teeth and skull • Agnathans: first vertebrates, had no teeth or jaws • Because we’re mammals, we have heterodont teeth • Form of teeth reflects function of animal’s diet • Teeth are most common fossil found and tell: – Age – Sex – Health – Mating systems – Behaviors

Tooth function • Aid the digestive system • Anterior dentition (incisors and canines) is responsible for digestion and posterior dentition (premolars and molars) physically process food, called mechanical digestion • For many mammals, anterior teeth have other functions – Grooming, threat displays, fighting

Tooth function • For mechanical digestion, there are 4 types: – Puncture/piercing (insects) • Small, sharp, needle-like – Shearing (leaves) • One side of molars is higher and sharper than the other – Crushing/grinding (fruit/omnivore) • Rounded, worn-down cusps – Tearing (meat) • Interlocking triangles

Measuring Human Biological Variation • Anthropometry: measurement of humans • Osteometry: measurement of skeletons

Anthropometry • Racist history • American Anthropological Association • 1930’s Franz Boaz, others • No differences in intelligence, athletic ability between races • Science offers limited definition of race • http: //www. understandingrace. o rg/history/index. html

• Humans are adapted to have lots of variation Human morphology varies • Human physiology varies • Human behavior varies • Caused by: • Genes (inherited from parents) • Environment • ALWAYS interact!

How do we measure variation? 1) biochemical: we can find evidence of gene flow and/or natural selection by looking at allele frequencies. 2) genetic distance data: the average measure of relatedness based on a number of traits. 3) demographic measures: e. g. migration patterns, birth and mortality rates 4) environmental correspondence: when looking for evidence of the effects of natural selection 5) anthropometrics: height, weight, and other measurements

Natural Selection shapes body proportions • Animals in cold places are large and stocky, with short limbs • Animals in hot places are smaller, thinner, longer limbed M. fuscata, Japan M. sinica, Sri Lanka

Contemporary human populations reflect this principle • Reduction of surface area less heat lost • Increase in body volume more heat produced • Body proportions are associated with climate • Crural index = tibia/femur ratio • Crural index correlated with height Femur Tibia

People in warm climates tend to have long limbs in proportion to height

Lets Get Down to Business; Measuring • Metric system!!! • Millimeters!!! • Don’t round off • • • 8. 1 Standing height Sitting height Popliteal height (PH) Seat height

8. 1 Comparing bodies to furniture: Do we fit? • Comfortable range for knee when sitting – Leg shouldn’t be hanging – Knees shouldn’t be up too high – Seat height needs to fall within that range to be good fit Ouch! Ah, just right!

8. 1 Comparing bodies to furniture: Do we fit? • PH + 3 cm = height of knees • Minimum angle of knees = (PH + 3 cm) * 0. 866 = PHmin • Maximum angle of knees = (PH + 3 cm) * 0. 996 = Phmax – Seat height needs to fall between the PHmin – PHmax range for comfort Ouch! Ah, just right!

Lab Groups • May work in all male/all female groups OR • KEEP data by sex separate • We will use the wooden chair for Seat Height • Enter your data in the table on the board

The Plan • For Exercise 6, just do 6. 1 and read pgs. 63 -64 • Exercise 8, enter data into Excel file • Work on the Handout, for exam prep for bones. • Each group has been given a box of bones to work with