Before coming to lab carefully read the previous pages on De

Before coming to lab carefully read the previous pages on Deuterostome Dissection a Chordata (Osteichthyes and Amphibia) Lab then answer these pre-lab questions. Be prepared to hand in your responses to the pre-lab questions at the start of lab. Explain five advantages of living a life in the water rather than moving onto land?

Solution

Advantages of living in water over land.

1. Management of weight:

Marine organisms do not have a well developed skeletal structures and muscles this prove an advantage over their terrestrial counterparts .As theses organisms are in water they do not have to support their body and hence conserve energy from supporting point of view. It is known that nearly 40% of the energy is spent in supporting their weight and an elaborate skeletal and muscular system is needed for the same.

2. Heat protection: In marine ecosystem drastic temperatures are not noticed between the different depths of the ocean so the organisms are not exposed to drastic temperature variations while in land dwelling organisms water becomes a limiting factor and these organisms have to adapt themselves to variations to extreme temperatures.

3.Water conservation: Terrestrial organisms always have to adapt themselves to conserve water as water becomes a limiting factor while in marine organisms as water is abundant these organisms really do not have to bother about water conservation mechanisms.

4. Respiratory system:The marine organisms have advantage over the terrestrial ones in the availability of oxygen for breathing.Since oxygen is dissolved in water these organisms take up oxygen through their gills.

5. Excretory system: due to availability of abundant water these organisms excrete ammonia in to the surrounding media while terrestrial animals have to conserve water even during excretion.