Problem 5 - Biology Concepts and Applications

Question

Which group has six legs and two antennae? a. crustaceans c. spiders b. insects d. horseshoe crabs

Step-by-Step Solution

Answer

b. insects

Step 1: Analyze Options

First, let's look at each option. Crustaceans can have various numbers of legs but typically have more than six. Spiders are arachnids and generally have eight legs. Horseshoe crabs are neither insects nor spiders.

Step 2: Identify Characteristics of Insects

Insects are characterized by having three pairs of legs (totaling six legs) and one pair of antennae (two antennae in total). This distinguishes them clearly from the other options.

Step 3: Match Insects to the Attributes

Since insects have six legs and two antennae, they fit the description perfectly, whereas the other groups do not.

Key Concepts

Six Legs

Insects are unique creatures found all across the globe. One of the defining features of insects is that they have six legs.
Each leg is attached to one of the three segments of an insect's thorax. This gives them three pairs of legs in total.

• These legs help them in varied activities like walking, jumping, grasping, or even swimming.
• The structure of the legs is fascinating and often adapted to suit their environmental needs.

For instance, grasshoppers have strong hind legs designed for jumping.
On the other hand, beetles might have legs suited for digging. The diversity in leg structure allows insects to thrive in many different habitats around the world.

Two Antennae

Another defining characteristic of insects is that they have two antennae. These antennae are usually located on their head. This pair of antennae are their sensory organs.

• Insects use antennae to smell and feel their environment.
• They can detect chemicals and even changes in air currents.

This is particularly helpful for finding food or mates and avoiding predators.
The design of the antennae can vary significantly between species. For example, moths have feathery antennae to detect pheromones, while bees have more simple antennae.
Despite the variations in form, antennae remain crucial for the insect's survival and interaction with its environment.

Arachnids

Arachnids are a different group altogether from insects. A common misconception is that they are similar since some might look alike. However, there are key differences.

• Arachnids have eight legs, unlike the six-legged insects.
• They do not possess antennae like insects do.

Common examples of arachnids include spiders, scorpions, and ticks.
These creatures are part of the larger arthropod family, like insects, but they belong to a distinct class called "Arachnida."
They have unique adaptations, such as the production of silk or venom in cases of spiders. These characteristics help them survive and excel in various ecosystems.