ANTHP105 Exam 2

Allen’s Rule

Body morphology; Animals adapted to warm climates will have longer limbs and appendages

Bergmann’s rule

Body composition; larger animals are found in colder environments and are more metabolically efficient at producing heat (less body heat radiated per kg body mass)

Biological adaptations for heat loss prevention

Body composition

Body morphology

Vasoconstriction

Biological adaptations for heat generation (thermogenesis)

Elevated BMR

Shivering (allostatic)

Non-shivering thermogenesis (NST) (allostatic)

Acclimatization to cold stress

Lower shivering threshold + faster initiation of NST

Hunter’s response

Increase in BMR

Increase in T3 production and tissue uptake via blood circulation (net blood T3 decline)

Increase in BAT (norepinephrine induces thermogenesis)

Thermogenesis is the change in…

supraclavicular temperature

Developmental adaptation to cold stress

developmental plasticity (ex. siberian children who spent winters outside exhibit more BAT thermogenesis)

how is BAT thermogenesis measured

infrared camera

Hypoxia-inducible factors (HIF)

Expressed when tissues experience hypoxia (fastest case of evolution); functions include…

• regulation of breathing rate

• increased number of RBC

• increased systemic blood flow

• increased growth of new blood vessels

• shift towards more oxygen-efficient biochemical pathways

Hypoxic ventilatory response

increased energy expenditure

increased rate and depth of breathing

acclimatization

arterial saturation (of O₂); initial abrupt fall, followed by slow increase over time.

Increase of O₂ saturation causes increases in…

• RBC

• Heart rate

• Blood flow

Tibetans and andeans both have… due to HIF-2 gene

Elevated blood flow

High lung capacity

lung capacity formula

vital capacity (air expired after inspiration) + residual volume (air remaining after expiration)

Due to HIF-2 gene, tibetans have…

High lung capacity due to high RV, only

Elevated hypoxic ventilatory response

Genetic adaptations

Due to HIF-2 gene, Andeans have…

High lung capacity due to high RV and VC

High hemoglobin concentration

Developmental adaptations

MC1R gene regulates production of which receptor

melanocortin-1

Functions of melanocortin hormone in regulating tanning response

Reduces production of harmful, reactive oxygen species

Enhances DNA repair