Marine Biology: Cephalopods and Annelids

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Questions and Answers

Which order of the Cleodidea is characterized by eight arms and two tentacles?

Sepioidea (correct)

Teuthoidea

Octopoda

Vampyromorpha

What is the primary characteristic that separates individual segments in annelids?

Nephridia

Fleshy parapodia

Septae (correct)

Metamerism

Which class of annelids includes the familiar earthworm?

Oligochaetea (correct)

Hirudinea

Myriapoda

Polychaeta

What evolutionary trait related to body structure is shared by arthropods and annelids?

Metamerism Signup and view all the answers

What is the primary function of fleshy parapodia found in polychaetes?

Locomotion and respiration Signup and view all the answers

Which of the following classes contains the highest number of annelid species?

Polychaeta Signup and view all the answers

What do nephridia in annelids primarily do?

Facilitate excretion Signup and view all the answers

What is the anterior structure of an annelid that assists in sensing the environment?

Prostomium Signup and view all the answers

What characteristic is shared among members of the class Oligochaeta?

Direct development without a larval stage Signup and view all the answers

Which feature distinguishes the subphylum Chelicerata from other arthropods?

Presence of chelicerae Signup and view all the answers

What is a significant evolutionary adaptation found in arthropods?

Highly protective exoskeleton that allows for mobility Signup and view all the answers

What reproductive feature is common in members of class Hirudinea?

Hermaphroditism with direct development Signup and view all the answers

What is a distinguishing feature of arachnids compared to insects?

Arachnids have no wings. Signup and view all the answers

Which class includes horseshoe crabs that have changed little since the Triassic period?

Merostomata Signup and view all the answers

Which of the following statements is true about the subphylum Trilobita?

They existed predominantly during the Cambrian period. Signup and view all the answers

Which of the following best describes the chelicerae in arachnids?

They serve in feeding and defense. Signup and view all the answers

What is the role of the tracheae system in arthropods?

To facilitate oxygen transportation directly to cells Signup and view all the answers

What is one adaptation of arachnids that enhances their ability to conserve water?

Adaptation of coxal glands. Signup and view all the answers

What kind of structural organization do somites provide in arthropods?

Development of specialized functional units Signup and view all the answers

How many pairs of appendages do arachnids possess in total?

Six pairs. Signup and view all the answers

Which statement correctly describes the significance of metamorphosis in arthropods?

It allows young and adult forms to occupy different ecological niches. Signup and view all the answers

Which type of eyes evolved from compound eyes in arachnids?

Lateral ocelli. Signup and view all the answers

What is a significant threat to humans that some arachnids pose?

Carrying harmful diseases. Signup and view all the answers

In which environment do most arachnids tend to thrive?

Warm and dry regions. Signup and view all the answers

What defines hemimetabolous insects?

They do not have a pupal stage. Signup and view all the answers

Which of the following best describes the adult stage of an insect that has undergone complete metamorphosis?

Imago Signup and view all the answers

Which type of insect relies on direct muscle action on the wings?

Primitive insect groups Signup and view all the answers

What is one characteristic of social insects like bees and ants?

They form large organized colonies. Signup and view all the answers

What mechanism allows male moths to detect female pheromones from great distances?

Specialized antennae Signup and view all the answers

Which of the following statements about insect senses is correct?

The range of frequencies insects hear is quite narrow. Signup and view all the answers

During which stage do insects undergo significant changes in form?

Pupal stage Signup and view all the answers

What type of reproduction involves a single fertilized egg dividing into multiple embryos?

Polyembryony Signup and view all the answers

Which group of invertebrates is characterized by having bilateral larvae but exhibiting radial symmetry as adults?

Echinoderms Signup and view all the answers

Which phylum is known for worm-like, lung or nasal parasitic species?

Phylum Pentastomida Signup and view all the answers

What is a defining characteristic of organisms in the Phylum Pogonophora?

Living in tubes without a mouth Signup and view all the answers

Which group has more in common with molluscs and annelids rather than arthropods?

Phylum Sipuncula Signup and view all the answers

Which class of echinoderms includes sea cucumbers?

Holothuroidea Signup and view all the answers

What is a significant feature of Phylum Tardigrada?

They possess eight unjointed legs Signup and view all the answers

During the Cambrian period, what significant event occurred regarding invertebrate phyla?

All major phyla of larger invertebrates became established Signup and view all the answers

Which phylum is recognized as having colonial filter feeders that secrete exoskeletons?

Phylum Ectoprocta Signup and view all the answers

Study Notes

Cephalopoda and Annelida

Orders of Cleodidea: Sepioidea (cuttlefish), Teuthoidea (squids), Vampyromorpha (deep sea squids, one species), Octopoda (octopuses).
Annelida Characteristics: High diversity with 15,000 species; includes earthworms (Oligochaeta) and leeches (Hirudinea).
Classes:
- Polychaeta: Mainly marine, distinct head, paired parapodia with setae, separate sexes, some asexual budding.
- Oligochaeta: Terrestrial and freshwater, few setae, hermaphroditic, direct development, includes Lumbricus (earthworm).
- Hirudinea: Freshwater and terrestrial, oral and posterior suckers, direct development, includes Hirudo (medical leech).
Morphological Features: Segmented bodies (metamerism), coelomates with septa between segments, leading to specialized organ systems.
Significance: Annelids exhibit complete regeneration, possess a complex nervous and circulatory system, and have a body plan with prostomium, segmented body, and pygidium.

Arthropoda

Diversity: Largest phylum, >900,000 species, over ¾ of all known species. Includes spiders, insects, crustaceans, etc.
Key Adaptations:
- Advanced cephalisation with enhanced sensory organs.
- Exoskeleton provides protection and mobility but requires ecdysis.
- Trachae system for efficient respiration.
Social Structures: Many species exhibit complex social interactions, e.g., social insects form colonies.
Development:
- Metamorphosis allows different food resource usage between young and adults.
- Types include incomplete metamorphosis (hemimetabolous) and complete metamorphosis (holometabolous).

Subphyla of Arthropoda

Trilobita: Extinct group, flourished before the Cambrian period, characterized by compound eyes and curling mechanism for protection.
Chelicerata: Includes horseshoe crabs, spiders, and scorpions; noted for lack of antennae and specialized appendages for feeding (chelicerae).
Class Arachnida: Contains spiders and scorpions; features include pedipalps for feeding or reproductive functions, four pairs of legs, and adaptations for terrestrial life.

Insect Characteristics

Wings and Development: Primitive groups with direct muscle control; advanced Neoptera utilize foldable wings; undergo molts and metamorphosis stages.
Sensory Systems: Highly specialized sense organs; some can detect specific light frequencies; developed communication systems in social insects.
Co-evolution: Insects evolved alongside plants, influencing plant defense mechanisms and habitat use.

Additional Invertebrate Phyla

Sipuncula: Benthic, burrowing worms without metamerism.
Echiura: Similar to sipunculans, with trochophore larvae.
Pogonophora: Tube dwellers without a digestive tract, absorb nutrients through tentacles.
Echinodermata: Marine-only phylum with about 7000 species. Includes starfish and sea cucumbers. Exhibit pentaradial symmetry in adults and bilateral symmetry in larvae.

Echinodermata Details

Classes:
- Asteroidea: Starfish and brittle stars.
- Echinoidea: Sea urchins and sand dollars.
- Holothuroidea: Sea cucumbers.
- Crinoidea: Sea lilies and feather stars.
Physiology: Echinoderms evolved from bilaterally symmetrical ancestors, underwent significant developmental changes leading to unique adult symmetry.

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Description

Explore the fascinating world of cephalopods and annelids in this quiz. Learn about the different orders of cephalopods like cuttlefishes, squids, and octopuses, as well as the diverse phylum of segmented worms, including earthworms and leeches. Test your knowledge on these intriguing marine creatures and their characteristics.