Question

What property of water allows aquatic organisms to function with far fewer supportive structures (tissues) than terrestrial organisms have?

Short answer

Based on the step-by-step solution, explain the property of water that allows aquatic organisms to function with fewer supportive structures than terrestrial organisms. The property of water that allows aquatic organisms to function with fewer supportive structures than terrestrial organisms is buoyancy. Buoyancy is the upward force exerted on an object submerged in a fluid, such as water, counteracting the force of gravity. This enables aquatic organisms to maintain their shape and function with less need for strong supportive structures like bones or exoskeletons. In contrast, terrestrial organisms require more rigid and robust structures to support their weight against gravity.

Step-by-step solution

Understanding the requirements of aquatic and terrestrial organisms

Aquatic organisms live in water, which has different properties than the air that terrestrial organisms live in. This difference in the environment results in varying requirements for the supportive structures that these organisms need to maintain their shape and function properly.

Identify the property of water that provides support

The key property of water that provides support to aquatic organisms is buoyancy. The buoyant force in water counteracts the force of gravity, making it easier for aquatic organisms to maintain their shape with less need for strong supportive structures such as bones or exoskeletons.

Explain buoyancy

Buoyancy is the upward force exerted on an object submerged in a fluid, such as water. This force is exerted because the fluid pressure increases with depth, causing a pressure difference between the top and bottom of the object. In water, the buoyant force acts to counteract the force of gravity, allowing aquatic organisms to float or have their weight partially supported by the water.

Examples of the impact of buoyancy on aquatic organisms

Due to buoyancy, many aquatic organisms have evolved to have lighter skeletons, less dense muscles, or even gas-filled chambers to help them float and maintain their shape with minimal need for supportive structures. For example, jellyfish lack a rigid exoskeleton, but their gelatinous bodies are held up in the water due to buoyancy. Similarly, many fish have swim bladders, which are gas-filled chambers that help them adjust their buoyancy, allowing them to float or sink in the water without expending much energy on supportive structures.

Comparison with terrestrial organisms

Terrestrial organisms, on the other hand, are not supported by buoyancy. They must have more rigid and robust structures, such as bones or exoskeletons, to maintain their shape and support their weight against the force of gravity. This results in the need for more extensive and specialized supportive tissues in terrestrial organisms as compared to aquatic organisms. In conclusion, the property of water that allows aquatic organisms to function with fewer supportive structures than terrestrial organisms is buoyancy. This force counteracts the effect of gravity, making it easier for aquatic organisms to maintain their shape and function with less reliance on robust supportive structures.

Key concepts

Aquatic Organisms

Aquatic organisms are fascinating creatures that thrive in water environments, benefiting from unique properties that water offers. One key aspect that allows them to survive and function efficiently is buoyancy. Buoyancy is an upward force exerted by the fluid on objects submerged in it. This upward force enables aquatic organisms to maintain their shape with minimal supportive structures.

Water's density plays a pivotal role in this. As organisms float or swim, they're supported by the water around them, lessening the need for heavy bones or hard shells to counteract gravity. For instance, jellyfish are mainly composed of a gelatinous substance and lack a rigid skeleton. However, water naturally supports their bodies, making them perfectly adapted to their environment.

Many aquatic creatures have evolved specialized features that help them control their buoyancy. Fish are prime examples; they have special organs called swim bladders, which are gas-filled chambers that allow them to move up and down in the water column swiftly and with little energy expenditure. Because of these adaptations, aquatic organisms often possess lighter skeletons or less dense musculature than their terrestrial counterparts.

Supportive Structures

Supportive structures in organisms are essential for maintaining shape, providing support, and facilitating movement. In aquatic environments, these structures can vary significantly from those found in terrestrial organisms, primarily due to the presence of buoyancy.

In water, the buoyant force diminishes the need for strong supportive structures like bones or exoskeletons since gravity's pull is lesser. For this reason, many aquatic organisms exhibit simpler or more flexible structural systems, such as cartilage instead of bone, or even buoyancy adaptations like gas bladders. This is in contrast to the more rigid and supportive tissues found in terrestrial organisms, which are necessary to combat the constant pull of gravity on land.

The efficiency of these adaptations ensures that energy is used wisely, helping aquatic organisms survive in their fluid environments. These lighter and more cost-effective supportive structures not only save energy but also allow for a diversity of shapes and sizes among aquatic life, contributing to the rich biodiversity found in water habitats.

Terrestrial Organisms

Terrestrial organisms, unlike their aquatic counterparts, spend their lives on land. They face different environmental challenges, primarily dealing with the force of gravity without the assistance of buoyancy. Because of this, these organisms require strong supportive structures to maintain their body shape, move, and support their weight.

Land-based creatures possess skeletons made of bone or exoskeletons to provide this critical support. These structures are needed to hold the organism upright and against the pull of gravity. For example, mammals have complex skeletal systems composed of various bones integrating with muscles to facilitate movement and support.

The robust supportive structures are energy-intensive to maintain, but they are crucial in allowing terrestrial organisms to perform daily activities, like walking, running, and standing. These systems are specially adapted to meet the demands of their environments, showcasing an evolutionary pathway distinct from that of aquatic organisms. This need for strong supportive structures invariably leads to greater complexity in the internal anatomy of terrestrial creatures.