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Question

Difficulty: EasyLower Invertebrates: Porifera, Coelenterata, Platyhelminthes, and Nematoda

Match each lower invertebrate phylum with its primary diagnostic structural feature.

  • PoriferaBody surface perforated by ostia
  • CoelenterataPossession of stinging nematocysts
  • PlatyhelminthesExcretory system consisting of flame cells
  • NematodaUnsegmented cylindrical body with a pseudocoelom

Answer

Porifera matches with 'Body surface perforated by ostia', Coelenterata matches with 'Possession of stinging nematocysts', Platyhelminthes matches with 'Excretory system consisting of flame cells', and Nematoda matches with 'Unsegmented cylindrical body with a pseudocoelom'.
Each lower invertebrate phylum is defined by signature structural features: Porifera have ostia for filter feeding, Coelenterata feature nematocysts for stinging, Platyhelminthes utilize flame cells for waste removal, and Nematoda possess cylindrical bodies with a pseudocoelom.

Step-by-Step Solution

1
Identify the key structural characteristic of Porifera.
Porifera are sponges whose body walls are covered in microscopic pores called ostia.
Water enters through ostia into the central cavity (spongocoel).
2
Identify the key defensive feature of Coelenterata.
Coelenterates possess nematocysts embedded within cnidocytes.
Nematocysts sting prey and serve as the main defensive mechanism in hydras and jellyfish.
3
Identify the specialized excretory organ of Platyhelminthes.
Platyhelminthes use flame cells.
Flame cells push waste fluid through excretory tubules via beating cilia.
4
Identify the body organization and body cavity type of Nematoda.
Nematodes have an unsegmented cylindrical shape with a pseudocoelom.
Unlike flatworms (acoelomate) and sponges (no tissue level), nematodes possess a false coelom (pseudocoelom).

Key Concept

Diagnostic structural characteristics of lower invertebrate phyla
Estimated Time:1m 0s
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Topics

Lower Invertebrates: Porifera, Coelenterata, Platyhelminthes, and Nematoda