Question

A disadvantage of an exoskeleton is that it a. cannot protect an animal’s internal organs. b. must be periodically shed, leaving the animal in a vulnerable state. c. does not provide any flexibility for the ease of movement of an animal. d. is a soft, easily damaged structure. e. cannot protect the outside of the body surface.

Short answer

The correct answer is b. must be periodically shed, leaving the animal in a vulnerable state.

Step-by-step solution

Understand the question

The question is asking for a disadvantage of an exoskeleton. An exoskeleton is a hard outer structure that provides structural support and protection to an animal's body, usually found in arthropods like insects, spiders, or crustaceans.

Evaluate each option

Evaluate each option in light of the function and characteristics of an exoskeleton.a. cannot protect an animal’s internal organs: Incorrect. One of the functions of an exoskeleton is to protect the inner organs.b. must be periodically shed, leaving the animal in a vulnerable state: Could be correct. This is referring to the process of molting, where the animal sheds its old and outgrown exoskeleton.c. does not provide any flexibility for the ease of movement of an animal: Incorrect. The exoskeleton is often jointed to allow movement.d. is a soft, easily damaged structure: Incorrect. An exoskeleton is usually a hard structure.e. cannot protect the outside of the body surface: Incorrect. The exoskeleton is the outermost layer and provides protection for the outside body surface.

Select the correct answer

The only option that accurately describes a disadvantage of an exoskeleton is b. must be periodically shed, leaving the animal in a vulnerable state.

Key concepts

Molting

Molting is a fascinating process that many animals, especially those with exoskeletons, undergo in order to grow. Animals with an exoskeleton cannot expand their rigid outer shell to accommodate their growing bodies. Instead, they must shed their existing exoskeleton and form a new, bigger one. This process is known as molting or ecdysis.

During molting, an arthropod like a crab or grasshopper will typically split its old exoskeleton through a set of specialized movements. These movements allow them to squeeze out of the old shell. While molting is essential for the growth of these creatures, it also leaves them temporarily vulnerable. Without their hard outer layer, they are at risk from predators and environmental hazards.

• The molting process includes a "pre-molt" phase where a new exoskeleton begins to form beneath the old one.
• Once the old exoskeleton is shed, the new one takes time to harden and provide adequate protection again.
• This phase can vary in duration based on species and environmental factors.

Understanding molting highlights an interesting trade-off in biology: the need for growth versus temporary vulnerability.

Arthropods

Arthropods make up a diverse group of animals with exoskeletons, including insects, spiders, crustaceans, and many more. They are arguably the most successful group of animals on the planet in terms of diversity and number. The exoskeleton, a defining feature of arthropods, plays a crucial role in their survival and evolutionary success.

The exoskeleton of arthropods is made primarily of a material called chitin, often toughened by a protein or mineral layer, which provides both protection and the means for the creature to attach its muscles for movement. Additionally, the exoskeleton is segmented and jointed in such a way that it allows flexibility and precise control over movement, the front runners being the complex joints found in an ant's leg or a crab's claw.

• Arthropods are incredibly adaptable due to their exoskeletal structure.
• The segmentation allows for specialized body parts, such as antennae, legs, and mouthparts.
• They inhabit nearly every ecosystem, from deep oceans to deserts.

This incredible adaptability and diversity mark arthropods as key players in both ecosystems and evolutionary history.

Biological Support Structures

Biological support structures refer to the parts of an organism that provide it with shape, protection, and an anchor for musculature. For arthropods and other exoskeleton-bearing creatures, this means their outer shell serves as their main support structure. This differs significantly from vertebrates that have an internal skeleton.

Exoskeletons serve numerous roles in supporting the creature's body. They protect internal organs, provide a surface for muscle attachment, and offer a shield against physical damage and dehydration. However, due to their rigidity, exoskeletons can't change in size and require the process of molting for growth.

• The exoskeleton is typically composed of chitin, a durable yet lightweight material.
• It also plays a role in reducing water loss in terrestrial arthropods.
• During molting, new exoskeletal layers form beneath the old ones to accommodate growth.

This dual role as both protector and supporter makes exoskeletons an evolutionary marvel in the animal kingdom.

Protection in Animals

Protection in animals is essential for their survival as it allows them to defend against predators and environmental threats. Exoskeletons provide an excellent example of how evolution has crafted intricate protective adaptations. By forming a hard, outer shell, animals like beetles and crabs are well-shielded against a variety of dangers.

Despite their protective power, exoskeletons come with limitations too. For instance, during the vulnerable stages of molting, the animal temporarily loses its strong shield. Furthermore, the rigidity of an exoskeleton prevents continuous growth, which requires strategic and timed molting periods.

• Protection through an exoskeleton helps deter predators physically.
• The hard outer layer also prevents moisture loss in many terrestrial species.
• Some exoskeletons have evolved coloration and textures that serve as camouflage or warning signs to predators.

In understanding the role of protection in animals, one can appreciate how exoskeletons provide both a formidable defense and a complex set of challenges in the thrilling theater of life.