Lecture 13

Who has bipedal hopping developed in?

Marsupials and rodents.

What two things help kangaroos to address muscle force per step?

Elastic energy storage in tendons and locomotor-respiratory coupling.

What relationship exists between locomotion costs and muscle force in kangaroos?

Costs = muscle force/step X step frequency.

How do kangaroos increase stride length?

By putting more energy into their jump without increasing stride frequency.

Why is bipdeal hopping an efficient means of locomotion

In kangaroos, the initial phase they walk → oddly metabolically expensive. When they get faster they change to hopping where by the metabolic costs decrease and stays relatively steady up to 30 km/hr

What skeletal adaptations do hopping animals have?

Long tibias, shorter forelimbs, short neck, longer tail, digital reduction, and a fibrocartilaginous patella.

What types of drag must flying organisms overcome?

Profile drag (whole body) and induced drag.

What are the two types of lift/propulsion in flying?

Active (flapping wings) and passive (gliding or soaring).

What adaptations do birds have for flight?

Light skeleton, rigid and compact body, and specialized wing and flight muscle structure.

What are the types of wings and how are they optimized for flying?

• Elliptical wings are very good at manoeuvrability e.g song birds

• Broad wings are very good at passive soaring e.g eagles

• Narrow wings are very good at dynamic soaring e.g albatross

• Tapered wings are very good at high speed e.g swallows

How do bats differ from birds anatomically?

Bats have no coracoid, an elongated carpus with a full number of digits and have more extensive patagiums.

What are the tarsal extensor muscles and how are connect with the knee extensors

M. gastrocnemius and M. flexor digitorum superficialis. These originate from the distal knee and and cause extension of the hock through a passive pull by the knee extensors which creates a power transfer.

What is the basis for physics of flying

• Lift must overcome weight

• Propulsion must overcome drag

What muscles are primarily involved in bird flight?

M. pectoralis and m. supracoracoideus.

What does the form of swimming involve to overcome drag?

Spindle-shaped body, smooth skin, and reduction of external appendages.

What is the difference between undulatory and oscillatory swimming?

Undulatory swimming uses the body axis, while oscillatory swimming uses appendages.

What are myomeres in fish?

Muscle units that contract sequentially for swimming motion.

What is the difference in the key rotation point for flapping in birds and bats

Birds use the shoulder joint, while bats rotate primarily at the point between the sternum and clavicle