Question

The development and utility of muscles in locomotion is a key characteristic of the animal clade.

First, defend this statement by reviewing the importance of muscle-driven locomotion among Bilaterians, keeping in mind their size and the limitations of protist locomotion-mechanisms. In your second paragraph, discuss key differences between the use of muscles for locomotion in worms with a hydrostatic skeleton and animals with hard internal or external skeletons. In your last paragraph, consider the pros and cons of the following statement - external appendages of radiates and bilaterians we have examined in Biol 227 require muscles to function effectively, even if they are not involved in locomotion.

Answer 1

Bilaterians have a well developed muscles which are used in both movement from one place to another and for holding things. The main limitations of protist locomotion-mechanisms is that they require medium of water for locomotion. They moved in water through pseudopods, cilia and flagella.

Longitudinal muscle are used by the worms to move from place to place. setae is present in worms which is used to move in forward direction, while jointed appendages which are attached to the body of insects helps in locomotion. Insects have skeleton that is present outside their body which is known as exoskeleton.

External appendages of radiates push the water outside in the backward direction and moved in the forward direction, while bilaterians moves from place to place through their legs which are specialized for this movement and their muscle in their hands are used for holding things.