Lecture 3: Multicellularity in Animals - Porifera and Cnidaria Flashcards
Multicellularity
The condition of being composed of multiple cells that are differentiated into various types with specialized functions. Allows for large body size
Kingdom Animalia
A classification of multicellular, heterotrophic organisms that evolved from colonial flagellated protists.
Choanoflagellates
Colonial flagellated protists considered the closest relatives to animals.
Phylum Porifera
A group of simple animals known as sponges, characterized by a cellular grade of organization and a water canal system.
Choanocytes
Specialized cells in sponges that facilitate water flow and filter feeding.
Phylum Cnidaria
A group of animals that includes jellyfish, corals, and sea anemones, characterized by a tissue grade of organization and the presence of nematocysts.
Diploblastic
An organism with two tissue layers (ectoderm and endoderm), as seen in Cnidaria.
Nematocysts
Stinging cells found in Cnidarians that are used for capturing prey.
Polyp
A sessile life stage of Cnidarians that is typically cylindrical and has a mouth surrounded by tentacles.
Medusa
A free-swimming life stage of Cnidarians, often umbrella-shaped with tentacles hanging down.
Class Anthozoa
A class within Cnidaria that includes corals and sea anemones.
Class Hydrozoa
A class within Cnidaria that includes hydroids and features both polyp and medusa forms.
Class Scyphozoa
A class within Cnidaria that includes jellyfish, where the medusa form is dominant.
Asexual reproduction
A mode of reproduction that does not involve the fusion of gametes, common in sponges and some Cnidarians.
Monoecious
An organism that has both male and female reproductive organs, as seen in sponges.
