L.15 Comparative Anatomy 2

Question 1

L.O.

Answer 1

• Relate the structure of the upper and lower limbs in humans to their respective functions.
• Compare the structure and function of the lower limb between humans and non-human animals with different locomotor habits.

Question 2

Comparing limbs within humans: Upper limb

Answer 2

• Adapted for sensing the environment
• Shorter
• Less robust
• Wider range of movement
• Bukly muscles around shoulder
• Thumb opposes other fumgers in hands

Question 3

Comparing limbs within humans: Lower limb

Answer 3

• Adapted for weight bearing and locomotion
• Longer
• More Robust for weight bearing
• Less range of movement with larger SA in locomotion
• Bulky muscles around hip, thigh and calf
• Big toe parallel with all toes on feet

Question 4

The lower limb

Answer 4

• Human and non-human lower limbs used for locomotion
• Some non-human animals do NOT have a fibula
• Some non-human animals have less metatarsals/ metacarpals and phalanges/ phalanx

Question 5

basic lower limb vertebra plan

Answer 5

Femur
Tibia and fibula
Tarsals
Metatarsals
Phalanges

Metatarsals + phalanges = Digits

Question 6

Adaptations to the basic plan

Answer 6

For animals that depend on running for survival:
- Increased length of distal segmants of limb allow easier distance to be covered in each step

By reducing the number of digits, energy is conserved more, therefore animals with less digits can have more stamina

Question 7

Predator Vs Prey differences in limbs

Answer 7

Animals that need maneuverability and short bursts of energy retain mamy digits

Animals that need to travel long distances have reduced digits 2 or 1

Question 8

Hooves, claws and nails

Answer 8

• Only primates and humans have flat nails at tips of digits
• Animals with claws are different but compressed medially- laterally
• Animals that walk on distal phalange only have hooves covering the bone
• ALL are growths of keratin, a protein derived from epidermis cells

Question 9

Retractable claws

Answer 9

Cats:
- Fold up off the grownd so they’re not worn down when walking
- The distal phalange is rounded and pivots on adjascent phalange, being held up by taut ligaments and pulled down by flexor tendons

Question 10

Jumping animals

Answer 10

Rabbits and kangaroos:
- Lower (hind) limbs are highly flexed to give muscle good leverage for taking off
- Large feet to rest on, but jump from toes
- In kangaroos, tail has a strong role in jumping and locomotion (therefore the cordal vertebrea is robust)

Question 11

Swimming animals

Answer 11

Sea lion:
- Lower limbs are used as flippers
- No weight bearing as they don’t walk
- Bones are different to land vertebrae, femur inside body and limbs smaller
- Feet are enlarged for maximum surface area

Question 12

Flying/ swinging animals

Answer 12

Bats:
- Lower limbs only used for hanging and spreading membranes as wings
- NO weight bearing
- Lower limb bones are very slender. Femur projects laterally from hip joint sockets

Question 13

Birds

Answer 13

• Highly adapted from lower limb plan
• Some bones fused (tibiatarsals)
• Elongation of distal segments
• Reduction of toes