Invertebrate Zoology Quiz on Mollusks & Arthropods

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Questions and Answers

What does the name 'Polyplacophora' signify in terms of chiton anatomy?

It signifies 'many plates', referring to their shell made of eight plates.

What is the primary feeding mechanism of Polyplacophora?

They use a radula to scrape algae off rocks.

How do the teeth of chiton compare in hardness and stiffness to other biomineral materials?

Chiton teeth are up to three times harder than human enamel and calcium carbonate-based shells of other mollusks.

What are the two main types of habitats where bivalves are found?

Bivalves are found in marine and freshwater habitats. Signup and view all the answers

What distinguishes bivalves from other classes of mollusks?

Bivalves are enclosed in two-part valves or shells. Signup and view all the answers

Name two examples of bivalves and their characteristic environments.

Examples include clams and mussels, often found in intertidal zones. Signup and view all the answers

What is one of the largest species of bivalves and its notable size?

The giant clam can be one meter in length and weigh up to 225 kilograms. Signup and view all the answers

What is the common ecological role of bivalves in the environments they inhabit?

They act as filter feeders, helping to maintain water quality and clarity. Signup and view all the answers

What is the main effect of increased CO2 levels on ocean water quality?

It makes water more acidic, which can dissolve the exoskeletons of crustaceans. Signup and view all the answers

What are the chelicerae and their function in the subphylum Chelicerata?

Chelicerae are specialized claw-like or fang-like mouthparts used for feeding. Signup and view all the answers

How are the body structures of chelicerates organized?

Their bodies are divided into two tagmata: a head/thorax and an abdomen. Signup and view all the answers

What key differences exist between deuterostomes and protostomes regarding embryonic development?

Deuterostomes develop the anus from the blastopore, while protostomes develop the mouth from it. Signup and view all the answers

What are the two phyla included in the superphylum Deuterostomia?

The two phyla are Echinodermata and Chordata. Signup and view all the answers

What is one of the most common preventive measures for nematode infections in humans?

Good sanitation practices help prevent nematode infections. Signup and view all the answers

What are the potential consequences of hookworm infections in humans?

Hookworm infections can lead to severe anemia by siphoning off iron and nutrients. Signup and view all the answers

How do pinworms commonly affect children in the US?

Pinworms cause itching by laying eggs in the folds of the anus. Signup and view all the answers

What is a notable characteristic of C. elegans that makes it useful for scientific research?

C. elegans is transparent, allowing researchers to easily observe internal changes. Signup and view all the answers

What was the significance of C. elegans in the field of genetics?

C. elegans was the first multicellular organism to have its entire DNA sequenced. Signup and view all the answers

What does the name 'Arthropoda' refer to in terms of physical characteristics?

The name 'Arthropoda' means 'jointed feet,' describing their jointed limbs. Signup and view all the answers

Why are arthropods considered dominant in the animal kingdom?

Arthropods account for an estimated 80 percent of all known animal species. Signup and view all the answers

What is the significance of the segmented body structure in arthropods?

Segmented bodies allow specialization into functional groups like head, thorax, and abdomen. Signup and view all the answers

What distinguishes Hexapoda from other arthropod groups in terms of leg structure?

Hexapoda is distinguished by having six legs, arranged in three pairs. Signup and view all the answers

Identify the main body segments of a hexapod insect.

The main body segments of a hexapod insect are the head, thorax, and abdomen. Signup and view all the answers

Why are insects considered significant in terms of species diversity?

Insects are significant because they comprise the largest class of arthropods and account for over 50% of all eukaryotic species. Signup and view all the answers

What role do wings play in the life of insects aside from locomotion?

Wings in insects are also used for thermoregulation, camouflage, and communication. Signup and view all the answers

What is the primary material that makes up the exoskeleton of arthropods?

Chitin is the primary material that makes up the exoskeleton of arthropods. Signup and view all the answers

Explain the process by which arthropods grow after they reach maturity.

Arthropods grow by molting, where they shed their exoskeleton, a process called ecdysis. Signup and view all the answers

Discuss the evolutionary significance of wings in insects compared to vertebrates.

Insect wings are considered a de novo development, unlike vertebrates which adapted existing structures (arms) for flight. Signup and view all the answers

List one advantage and one disadvantage of having an exoskeleton.

An advantage is that it protects the body, while a disadvantage is that it limits growth size. Signup and view all the answers

Name two orders of winged insects that existed during the Carboniferous period.

Two orders of winged insects that existed during the Carboniferous period include the Meganeuridae and the Paleozoic dragonflies. Signup and view all the answers

What is the purpose of the head segment in hexapods?

The head segment houses the mouthparts and sensory organs, crucial for feeding and navigation. Signup and view all the answers

Why do marine arthropods, like lobsters, add calcium salts to their exoskeleton?

Marine arthropods add calcium salts to increase the strength of their exoskeleton. Signup and view all the answers

What physiological process must arthropods undergo to grow, and what is it commonly called?

Arthropods undergo molting, which is commonly called ecdysis. Signup and view all the answers

What adaptive advantage do insects have due to their diverse respiratory system?

Insects have a highly efficient tracheal respiratory system that allows for direct oxygen transport to tissues. Signup and view all the answers

Name the five subphyla of Phylum Arthropoda.

The five subphyla are Trilobita, Hexapoda, and three others not specified in the text. Signup and view all the answers

Describe the role of the cuticle in arthropods.

The cuticle acts as a protective covering for the arthropod's body. Signup and view all the answers

How does the exoskeleton of arthropods contribute to their ability to colonize land?

The exoskeleton prevents desiccation, allowing arthropods to move on land without drying out. Signup and view all the answers

What are the two types of metamorphosis in insects and provide an example of each?

Incomplete metamorphosis, exemplified by cockroaches, includes the stages of egg, nymph, and adult. Complete metamorphosis, seen in butterflies, follows the stages of egg, larva, pupae, and adult. Signup and view all the answers

How do social insects communicate and maintain their colony structure?

Social insects communicate and maintain colony structure using pheromones, which are external chemical signals. Signup and view all the answers

What ecological roles do insects fulfill in their environments?

Insects play critical ecological roles such as soil aeration, decomposition, pest control, pollination, and providing nutrition for wildlife. Signup and view all the answers

Why are Drosophila melanogaster considered important model organisms in genetics?

Drosophila melanogaster are important model organisms due to their easy lab cultivation, large offspring numbers, four pairs of chromosomes, and identifiable traits. Signup and view all the answers

What percentage of food production is reliant on insect pollination, and which insect is responsible for a significant portion of this?

About one third of food production relies on insect pollination, with the European honeybee, Apis mellifera, responsible for approximately 80% of this. Signup and view all the answers

What significant consequences could arise from the absence of insects in ecosystems?

Without insects, there would be no decomposition, leading to accumulation of waste, and food chains would collapse, potentially endangering human survival. Signup and view all the answers

How does the physical structure of insects influence their growth and development?

Insect growth is constrained by their exoskeleton, requiring them to undergo a series of molts as they develop. Signup and view all the answers

List some products derived from insects that are beneficial to humans.

Beneficial products derived from insects include silk, honey, and wax. Signup and view all the answers

Study Notes

Invertebrates

Invertebrates are animals that lack a cranium and a defined vertebral column or spine.
These animals make up nearly 97% of the animal kingdom.
Examples, include sponges, flatworms, jellyfish, nematodes, arthropods, mollusks, and annelids.
Skeletons can be made of many things, like bones, or exoskeletons or hydrostatic skeletons.

Animal Phylogenetic Tree

The phylogenetic tree of animals is based on morphological, fossil, and genetic evidence.
All animals share a common ancestor.
Animals are a monophyletic clade.
Metazoa (animals) includes organisms with tissues.
Eumetazoa (animals with specialized tissues) includes organisms with tissues.

Phylum Porifera (Sponges)

Sponges are among the simplest animals.
Sponges are generally considered to be at the base of the animal phylogenetic tree.
They are aquatic, living mostly in marine environments.
Approximately 5,000 named species of sponges are known and likely thousands more to be classified.
Sponges lack true tissues and have an asymmetrical body plan.
Sponges have choanocytes, which are flagellated feeding cells similar to choanoflagellates.

Phylum Cnidaria (Jellyfish, Corals, Anemones)

Cnidarians are mostly marine.
There are over 11,000 species.
These animals have a diploblastic body plan with two tissue layers.
They have radial symmetry.
Cnidarians have cnidocytes which have nematocysts that are used for prey capture.

Phylum Platyhelminthes (Flatworms)

Most flatworms are acoelomates.
Flatworms lack a true coelom; the mesoderm forms a solid mass between the outer epidermal surface and the digestive system.
Flatworms lack a complete gut, having only a single opening that serves as both mouth and anus or they lack a gut entirely.
There are over 20,000 different flatworm species catalogued.
Most are free-living in moist environments, but some species are parasitic.

Phylum Mollusca (Snails, Clams, Squids)

Mollusks are a diverse group with a wide range of morphologies.
They are predominantly marine but some live in freshwater or moist terrestrial habitats.
Some species have shells, others do not.
They have a muscular foot used for movement.
Most mollusks are dioecious.
A radula is used by most for scraping food.
Mollusks are coelomates.

Phylum Annelida (Segmented Worms)

Annelids are segmented worms with a body plan that has repeated internal and external morphological features.
They have a closed circulatory system and respiration can be across moist skin.
Most annelids are coelomates with bilateral symmetry.
Annelids are found in various aquatic and moist terrestrial habitats.
There are approximately 22,000 described species of annelids.

Phylum Nematoda (Roundworms)

Nematodes are tiny, slender worms.
They are found nearly every ecosystem from marine to terrestrial environments.
They come in free-living and parasitic forms.
They exhibit bilateral symmetry and are triploblastic.
They have a complete digestive system.
They have a nervous system with head ganglia and tail ganglia.
Most species are dioecious (separate sexes)
There are between 40,000 and 100,000 species.

Phylum Arthropoda (Insects, Arachnids, Crustaceans)

Arthropods have a chitinous exoskeleton that they shed periodically during molting.
They have segmented bodies with jointed appendages.
There are approximately 1.134 million described species worldwide.
Arthropods have a variety of body forms, mouthparts, antennae, legs, and tail parts.
Arthropods have an open circulatory system, with a central body cavity called a hemocoel.

Subphylum Hexapoda (Insects)

Insects have a head , thorax and abdomen.
The insects are the most diverse and numerous group of arthropods.

Subphylum Myriapoda (Millipedes, Centipedes)

Myriapods are bilaterally symmetrical and have many legs.
They are primarily terrestrial and have a variety of functional groups.

Subphylum Crustacea (Crabs, Lobsters, Shrimp)

Crustaceans are aquatic, and have a variety of forms due to different morphologies and appendages
They have a complex segmented body.

Subphylum Chelicerata (Scorpions, Spiders)

Chelicerates have a body plan with a head/thorax and an abdomen tagma.
They do not have antennae.
They have appendages called chelicerae that have a claw like or fanglike structure.
These animals are mostly terrestrial.

Phylum Echinodermata (Sea Stars, Sea Cucumbers)

Echinoderms evolved from bilateral animals, but have a radial symmetry as adults.
Echinoderms have an endoskeleton made up of small bony plates covered by epidermis.
There are about 7,000 described living species.
Many are exclusively marine.
They have a water vascular system that is used for movement, feeding, gas exchange, and sensory reception.

Phylum Chordata (Vertebrates and Invertebrates)

Chordates have a dorsal hollow nerve cord, a notochord, pharyngeal gill slits, and a post-anal tail at some stage in their life.
There are three subphyla: Urochordata, Cephalochordata, and Vertebrata.
Vertebrates include all animals with a backbone.

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Description

Test your knowledge on the anatomy and ecology of mollusks, specifically Polyplacophora and Bivalves, as well as the characteristics of Chelicerata. This quiz covers feeding mechanisms, habitat distinctions, and environmental impacts related to these invertebrates. Challenge yourself with questions about their roles in ecosystems and developmental biology.