Compare spaces that have channels coming from

Compare and contrast the adaptations within amphibians and
reptiles that help with climbing.

 

Locomotion within reptiles and amphibians has expanded into
many forms, but one of the most commonly seen in both classes is the use of
climbing. Both reptiles and amphibians have developed substantially different
ways of overcoming this form of locomotion, comparing geckos to tree frogs
shows how they have accomplished the same goal but using drastically different
methods. Geckos adhesive abilities come from the function of their feet and the
use of hundreds of thousands of spatulae, that create the force needed to allow
them to climb (Russell, 2002). whereas frogs use large pads that are covered in
microscopic channels that lead to a mucous gland that helps them stick to
surfaces, which acts as their adhesive mechanism.

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Geckos adhesive capabilities come directly from the function
and structure of their feet (Russell 2002). On the underside of their toes are
adhesive pads, made up of hundreds of thousands of microscopic setae. Each seta
splits into hundreds of spatulae tips. When the gecko places his foot down the
said spatulae spread out maximizing their surface area. a single seta can
generate enough force that is required to hold the animal’s body weight (Autumn
and Peattie, 2002). To break these bonds geckos, use Macroscale detachment of
the adhesive pads, this happens through digital
hyperextension in both geckos (Autumn and Peattie, 2002; Russell, 2002) and
frogs (Hanna and Barnes, 1991). The peeling motion of digital hyperextension
may minimise the force needed to overcome the adhesion produced by the foot.
Removal of a small region of the pad at a time by pealing is easier as only a
small area is being separated from the substrate at any given time.

 

Frogs possess large pads at the tip of each toe that provide
adhesion while climbing. these Enlarged toe pads have evolved in a number of
different frog families. Generally, the toe is constructed of a pad with a
specialized epidermal layer, the epidermal cells are shaped into peg-like
structures, between these structures there are spaces that have channels coming
from mucous glands. These mucous glands supply the fluid that then forms part
of the adhesive mechanism. frogs toe pads allow them to adhere to surfaces
through wet adhesion. Wet adhesion is when surface tension and viscous forces
keeps the animal attached using a fluid filled joint that resists cavitation, how
strong the force is, is directly dependent on the size of the toe pad. frogs
must also be able to detach their toe pads, Frogs detach their toe pads by
peeling, depending on the direction of locomotion changes how the pads are
going to be detached, when the frog is moving in a forward direction up a vertical
surface the pads are being peeled off from the rear forwards. When walking backwards
down a vertical substrate peeling of the toe happens starting at the front of
the pad and then ending at the back. (HANNA, G.,
Jon, W. and BARNES, 1991)

 

 

 

 

 

Other examples of reptiles that have special adaptations for
vertical locomotion would be chameleons, Chamaeleon’s are highly specialized arboreal
lizards with a laterally compressed body, zygodactylus feet and a prehensile
tail. While traveling along branches chameleons have a more upright limb
posture and walk in a more mammal-like way. Traveling between branches is not done by jumping or by the use of
sticky pads but by reaching
with their forelimbs and supporting themselves by their hindlimbs and tail
until a new perch is grasped. (Peterson, J.A.,
1984) the bones in the feet are developed differently to form limbs that
allow chameleons to hold on to narrow substrates (Peterson, 1984). arboreal
species usually have longer tails on average than that of terrestrial reptiles,
this is particularly showing in chameleons who possess long prehensile tails
that help with their locomotion and balance. Although chameleons have adapted
to be able to live within the trees they have had to compromise on their
running ability. Other papers on chameleon locomotion depicts a trade-off
between running and climbing performance. Moreover, it was suggested that the majority
of arboreal species possessed a greater number of slow, strong, muscles fibres
within its limbs (Peterson, J.A., 1984).

 

               

 

 

Autumn, K., Dittmore, A.,
Santos, D., Spenko, M. and Cutkosky, M., 2006. Frictional adhesion: a new angle
on gecko attachment. Journal of Experimental Biology, 209(18),
pp.3569-3579.

Autumn, K. and Peattie,
A.M., 2002. Mechanisms of adhesion in geckos. Integrative and
comparative biology, 42(6), pp.1081-1090.

Autumn, K., Hsieh, S.T.,
Dudek, D.M., Chen, J., Chitaphan, C. and Full, R.J., 2006. Dynamics of geckos
running vertically. Journal of experimental biology, 209(2),
pp.260-272.

Emerson, S.B. and De Jongh,
H.J., 1980. Muscle activity at the ilio?sacral
articulation of frogs. Journal of Morphology, 166(2),
pp.129-144.

HANNA, G., Jon, W. and
BARNES, W.J., 1991. Adhesion and detachment of the toe pads of tree
frogs. Journal of Experimental Biology, 155(1),
pp.103-125.

Russell, A.P., 2002.
Integrative functional morphology of the gekkotan adhesive system (Reptilia:
Gekkota). Integrative and Comparative Biology, 42(6),
pp.1154-1163.

Peterson, J.A., 1984. The
locomotion of Chamaeleo (Reptilia: Sauria) with particular reference to the
forelimb. Journal of Zoology, 202(1), pp.1-42.