Podcast Beta
Questions and Answers
What is the free swimming larva form of certain oviparous species called?
What unique cell type is characteristic of the phylum Cnidaria?
How long is the fossil history of Cnidarians believed to span?
In what type of habitats are most Cnidarians found?
Signup and view all the answers
What is a notable characteristic of colonial hydroids in terms of their habitat?
Signup and view all the answers
Which of the following describes how Cnidarians prey on other organisms?
Signup and view all the answers
How do some organisms utilize the stinging cells of Cnidarians for their own benefit?
Signup and view all the answers
In the context of mutualism, how do anemones benefit from living on hermit crab shells?
Signup and view all the answers
Which class of cnidarians is known as the true jellyfish?
Signup and view all the answers
What type of body form do polyps exhibit?
Signup and view all the answers
What is a key advantage of the dimorphism seen in some cnidarians?
Signup and view all the answers
Which cnidarian class is recognized for its variety of living forms, including hydroids and fire corals?
Signup and view all the answers
What is a distinguishing feature of cubozoans?
Signup and view all the answers
What type of symmetry do hexacorallians exhibit?
Signup and view all the answers
Nematocysts play a critical role in which aspect of cnidarian biology?
Signup and view all the answers
What characteristic is typical of the medusa form of cnidarians?
Signup and view all the answers
How do sea anemones primarily trigger feeding behavior?
Signup and view all the answers
Which class contains both hard corals and sea anemones?
Signup and view all the answers
Which of the following statements about the class Anthozoa is correct?
Signup and view all the answers
What is the size range of sea anemones?
Signup and view all the answers
What is the significance of chitin-like material in nematocysts?
Signup and view all the answers
Which subclass of Anthozoa features soft and horny corals?
Signup and view all the answers
What is unique about the polyp of the species Tripedalia cystophora?
Signup and view all the answers
How do sea anemones typically attach to their environment?
Signup and view all the answers
What is the main advantage of the skin mucus for Nomeus fish in relation to the Portuguese man-of-war?
Signup and view all the answers
What is the primary composition of the bell in true jellyfish of the class Scyphozoa?
Signup and view all the answers
Which process describes the formation of saucer-shaped buds in the life cycle of Scyphozoa?
Signup and view all the answers
What distinguishes the nervous system of Scyphozoa from that of hydrozoans?
Signup and view all the answers
Which of the following statements is accurate regarding the reproductive process of true jellyfish?
Signup and view all the answers
What is the typical size range for the medusae of box jellyfish in the class Cubozoa?
Signup and view all the answers
What evolutionary characteristic differentiates Scyphozoa from other less advanced groups?
Signup and view all the answers
How do the tentacles of the Portuguese man-of-war primarily function?
Signup and view all the answers
What triggers the discharge of a nematocyst in cnidarians?
Signup and view all the answers
Which class does Obelia belong to within the cnidarian phylum?
Signup and view all the answers
What is the role of cnidocytes in cnidarians?
Signup and view all the answers
What distinguishes the neural net of cnidarians from that of more complex animals?
Signup and view all the answers
What happens after partial extracellular digestion in the feeding polyp of Obelia?
Signup and view all the answers
Which of the following statements about nematocysts is true?
Signup and view all the answers
What reproductive process occurs when Obelia buds off a gonangium?
Signup and view all the answers
How do cnidocytes differ during development?
Signup and view all the answers
Study Notes
Reproductive Characteristics
- Oviparous species release sperm and eggs into water currents.
- Larval stage known as parenchymula is free-swimming and flagellated.
- After settling, larval flagellated cells transform into choanocytes.
Phylum Cnidaria
- Contains over 9,000 species and includes organisms like jellyfish, sea anemones, and corals.
- Named after cnidocytes which harbor stinging organelles called nematocysts.
- Cnidarians have the longest fossil history, dating back approximately 700 million years.
- Predominantly marine, with a few freshwater species; most are sessile or slow-moving but are efficient predators.
Habitat and Distribution
- Abundant in shallow marine waters, especially in warm, tropical regions; no terrestrial species exist.
- Colonial hydroids settle on shells, rocks, and manmade structures in shallow waters.
- Free-swimming medusae are found in open seas and lakes.
Symbiotic Relationships
- Cnidarians often engage in symbiotic relationships; for example, hydroids may provide protection to hermit crabs and obtain food from them.
- Algal cells within cnidarians (notably reef-building corals) assist with nutrient acquisition.
Economic Importance
- While many cnidarians lack significant economic value, reef-building corals are critical for fishing, tourism, and marine trade.
Classification of Cnidarians
- Four primary classes:
- Hydrozoa (hydroids, fire corals, Portuguese man-of-war)
- Scyphozoa (true jellyfish)
- Cubozoa (box jellyfish)
- Anthozoa (sea anemones, stony and soft corals)
Morphological Types
- Two main forms: Polyp (sessile) and Medusa (free-swimming).
- Polyp examples include sea anemones, which do not have a medusae stage.
- Medusae have bell-shaped bodies and a more prominent role in certain life cycles.
Nematocysts
- Over 20 types exist; structure includes a coiled thread or filament enclosed in a capsule.
- Cnidocytes, which contain nematocysts, respond to tactile stimulation, allowing for prey capture or defense.
Nervous System
- Cnidarians exhibit neural nets, lacking a centralized nervous system, suited for their radial symmetry.
- Nerve cells exhibit unique features such as neurotransmitter release on both sides of a synapse.
Class Specifics
- Class Hydrozoa: Includes colonial forms like Obelia that exhibit both polyp and medusa stages; diverse feeding strategies.
- Class Scyphozoa: Features jellyfish, with complex locomotion and a two-stage life cycle from fertilized egg to medusa.
- Class Cubozoa: Box jellyfish are potent predators; life cycles include an inconspicuous polyp stage.
- Class Anthozoa: Exclusively polyp; includes varied forms from vibrant sea anemones to complex coral structures.
Feeding and Behavior
- Sea anemones are carnivorous, capable of consuming small fish and plankton.
- Movement is achieved through contraction of well-developed muscles; they react to environmental stimuli.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fascinating characteristics of Phylum Cnidaria, which includes over 9,000 species like jellyfish and corals. Learn about their reproductive methods, habitat distribution, and symbiotic relationships in this engaging quiz. Delve into their unique adaptations and fossil history that spans millions of years.
