Quiz On Invertebrates, Arthropods And Arachnids!

Invertebrates do not have backbones. Invertebrates are animals that lack a vertebral column, which is also known as a backbone. Instead, they have a soft body structure and rely on other means of support and movement, such as exoskeletons or hydrostatic skeletons. In contrast, vertebrates, which include mammals, birds, reptiles, amphibians, and fish, have a well-developed backbone that provides support and protection for their internal organs.

Octopus is an invertebrate because it lacks a backbone or vertebral column. Invertebrates are animals that do not possess a spinal column, and octopuses belong to the phylum Mollusca, which includes various soft-bodied creatures. They have a distinct body structure, including a mantle, eight arms, and a beak-like mouth. Their lack of a backbone allows them to have a flexible and agile body, enabling them to maneuver swiftly in water.

A centipede is not an arachnid because it belongs to the class Chilopoda, while arachnids belong to the class Arachnida. Arachnids include spiders, ticks, and mites, which have two body segments and eight legs. In contrast, centipedes have many body segments and numerous legs, typically ranging from 30 to 354. Therefore, centipedes are not classified as arachnids.

A starfish is not an arthropod because it belongs to a different phylum called Echinodermata. Arthropods are characterized by having jointed appendages and an exoskeleton, while starfish have a radial symmetry and a water vascular system. Therefore, starfish do not fit the criteria to be classified as arthropods.

The red hourglass shape is seen on the underside of the black widow spider. This distinctive marking is a key characteristic of the black widow species and helps to identify it. The hourglass shape is usually bright red in color, contrasting with the spider's black body. It serves as a warning signal to potential predators, indicating that the black widow is venomous and should be avoided.

The correct answer is brown recluse because the question asks for the spider shown, and without any visual context, it is impossible to determine the exact species of spider. However, among the given options, the brown recluse is the only one that matches the description.

Trilobites were an ancient group of arthropods that lived from the Cambrian period to the Permian period, approximately 540 to 250 million years ago. They were one of the most diverse and successful groups of arthropods, with over 20,000 known species. However, they became extinct during the Permian mass extinction event, which wiped out approximately 96% of all marine species. Trilobites are now only known from fossils and are no longer found in the modern world.

Insects have three pairs of legs, which means they have a total of six legs. This is a characteristic feature of insects and distinguishes them from other animals. Each leg is attached to a specific segment of the insect's body and is used for various purposes such as walking, climbing, and grasping. Having six legs allows insects to move efficiently and navigate their environment.

As some arthropods mature, they undergo a process called metamorphosis, during which they form a protective covering known as a cocoon. This cocoon serves as a shelter for the arthropod while it undergoes further development and transformation. The cocoon provides a safe environment for the arthropod to grow and change, protecting it from predators and harsh environmental conditions. Once the arthropod has completed its metamorphosis inside the cocoon, it emerges as a fully developed adult.

The brown recluse spider is dangerous to humans because its venom can cause necrotic (dead tissue) wounds. Its bite can lead to symptoms such as pain, redness, and blistering, which may progress to an open ulcer. In some cases, it can cause systemic symptoms like fever, nausea, and muscle pain. If left untreated, the bite can result in severe tissue damage and potentially life-threatening complications. Therefore, it is important to exercise caution and seek medical attention if bitten by a brown recluse spider.