Problem 7 - Biology: Concepts and Applications

Question

A spider's chelicerae ____________ . a. detect light b. inject venom c. produce silk d. eliminate excess water

Step-by-Step Solution

Answer

The correct answer is b. inject venom.

Step 1: Identify Keywords in the Question

Look at the main term in the exercise: 'spider's chelicerae'. This refers to specific parts of a spider used for feeding and defense. The function of chelicerae will determine the correct answer.

Step 2: Analyze Each Option

- a. Detect light: Spiders have eyes for detecting light; chelicerae are not involved in this function. - b. Inject venom: Chelicerae are often equipped with fangs that inject venom into prey. - c. Produce silk: Spiders use specialized glands known as spinnerets, not chelicerae, to produce silk. - d. Eliminate excess water: Spiders use other physiological methods, not chelicerae, for water regulation.

Step 3: Select the Correct Option

Based on the analysis, option 'b. inject venom' is the function of a spider's chelicerae because they are used to capture and envenom prey.

Key Concepts

Chelicerae

Chelicerae are essential components of a spider's anatomy. These appendages sit near the mouth of the spider and play multiple critical roles. Most notably, they're involved in the feeding process. They typically consist of a base segment and a movable fang, which is used for piercing prey.
Spiders rely heavily on their chelicerae to not only capture prey but also defend themselves.

• Spiders use their chelicerae to grip, crush, or slice their prey's body.
• The chelicerae are hollow, housing ducts connected to venom glands.
• The fang, the sharp part of the chelicerae, injects venom into the prey to subdue or kill it.

These tasks are facilitated by the powerful muscles and hinged design of the chelicerae, allowing spiders to execute precise and effective movements during an attack. Understanding the structure of chelicerae gives insight into how spiders have adapted as successful predators.

Venom Injection

Venom injection is a crucial function of a spider's chelicerae. The venom, once injected, acts quickly to immobilize and begin digesting the prey's internal tissues. This process is essential in the feeding strategy of many spiders.

• Venom has enzymes that start the digestion process even before the spider consumes its prey.
• The injection method is highly efficient, allowing spiders to tackle prey much larger or stronger than themselves.
• Many spiders can control the amount of venom injected, which can vary based on the threat level or prey type.

Using chelicerae for venom injection also provides a physiological advantage, enabling the spider to reduce energy exerted during hunting.
This adaptation is a perfect example of nature’s efficiency in predator-prey interaction.

Arachnid Physiology

Arachnid physiology refers to the distinctive body systems that define this group of creatures, including spiders. Spiders, as members of the arachnid class, exhibit unique physical characteristics and bodily processes.

• Arachnids generally have two main body parts: the cephalothorax and abdomen.
• They possess eight legs, which is a defining trait separating them from insects, which have six.
• Unlike insects, arachnids do not have wings or antennae.

Additionally, their respiratory systems are varied; many rely on book lungs or trachea for gas exchange. These adaptations give arachnids, and particularly spiders, special capabilities for survival in a variety of environments.
Understanding arachnid physiology helps to appreciate the complex mechanisms behind their predatory skills and ecological roles.