Get a Grip! 26/6/12, Evolution

Activity 1: to observe different way of holding objects with our hands

Some interesting words were used to describe ways of holding objects. Here are a few discussed in class.

1) Gripping with thumb and index (pinch)

2) Pinching with index and middle (scissors)

3) 4 fingers at 1 side of object, thumb at other side.

4) 4 fingers around object (small/thin/long) thumb curled and in contact with other side.

5) palm and 4 fingers curling around object.

6) 2 palms touching (scooping)

7) same as 2) but using 4th and last finger

Activity 2: observing and drawing of how I hold my object.

(shown at right)

description of the object: 4 fingers curled around object and thumb curled and on top of the 4 fingers.

My description was accurate enough for my partner to guess how I had held the object. 

Activity 3: Observation of how gorilla moves about and physical appearance of arms, legs, hands, and feet 

This is with reference to the video: OBSERVING PRIMATES

Observations made and differences highlighted between humans' and gorillas' limbs:

FEET: Gorilla has huger gap between big toe and other toes compared to humans.

HANDS: Gorilla has wider digits and "furrier" hands compared to ours.

Some motions of the gorilla: The gorilla moves on fours, with its fists clenched. However, sometimes, it walks on twos. Its limbs, though,  are bent and swing to and fro.

WHY are there such differences?

The black hands (or outer covering) is to enable it to camouflage in its surroundings, so that its predators/prey will not find it.


As for the feet, before we go on, there is one thing to be mentioned here.


Humans have what are known as opposable thumbs. This is because the thumb can only move in the opposite direction of the other 4 fingers. Likewise, this feature is present in the gorillas and most primates. This adaptation is useful to grab items (or stuff, as I prefer to word it). However, some monkeys have prehensile tails (a tail adapted to hold STUFF) to carry out the above mentioned action. 


Moving on...


Now, since gorilla has to grasp on branches and move, therefore, they have opposable toes to grip the branches firmly in order not to lose their balance. 


Enough about gorillas, so let's moo-ve on...


Activity 4: Questions on how primates move.


Some questions to think about...


1) If other primates have opposable toes to grasp onto branches, then why do they need a prehensile tail to grasp onto objects?
2) Why do gorillas need to move in fours when they can easily move in twos like use humans?
3) Why do gorillas have to clench their fist and walk in fours, rather than placing their palms flat on the ground?


Well that's about all for now. Will continue soon so bb :)