Kingdom Animalia: Phylum Porifera

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Questions and Answers

What distinguishes the Eumetazoa from the Parazoa?

Eumetazoa lack a digestive system while Parazoa have a complete gut

Eumetazoa have differentiated tissues while Parazoa lack tissues (correct)

Eumetazoa are sessile while Parazoa have motility

Eumetazoa have radial symmetry while Parazoa have bilateral symmetry

How do sponges (Phylum Porifera) feed?

By extending tentacles to capture prey

By releasing cnidocytes to sting and capture prey

Through phagocytosis by choanocytes lining the spongocoel (correct)

By extending a lophophore to filter feed

Which of the following best describes the body plan of cnidarians?

Triploblastic with radial symmetry and a true coelom

Triploblastic with bilateral symmetry and a pseudocoelom

Diploblastic with radial symmetry and a gastrovascular cavity (correct)

Diploblastic with bilateral symmetry and a complete digestive system

What is the distinguishing feature of the Ecdysozoa clade?

They undergo ecdysis (molting of the exoskeleton) Signup and view all the answers

Which of the following statements about the phylum Acoela is correct?

They are triploblastic but lack a digestive tract Signup and view all the answers

How do sponges (Phylum Porifera) reproduce?

Asexually through budding and fragmentation; sexually by releasing gametes Signup and view all the answers

Which of the following statements about sponges (Phylum Porifera) is correct?

They are sessile as adults but motile as larvae. Signup and view all the answers

What is the primary function of choanocytes in sponges?

To direct water flow and trap food particles. Signup and view all the answers

Which of the following is a characteristic of the Radiata group?

They display radial symmetry. Signup and view all the answers

What is the primary function of cnidocytes in cnidarians?

To capture prey using nematocysts. Signup and view all the answers

Which of the following phyla is characterized by a trochophore larva or lophophore feeding structure?

Lophotrochozoa Signup and view all the answers

Which of the following statements about the Ecdysozoa clade is correct?

They undergo ecdysis, or molting of their exoskeleton. Signup and view all the answers

Which of the following statements about Acoela is correct?

They lack a digestive tract and absorb nutrients across their surface. Signup and view all the answers

What is the primary function of the spongocoel in sponges?

To serve as a central cavity for water circulation. Signup and view all the answers

Which of the following statements about cnidarians is correct?

They possess a primitive nerve net. Signup and view all the answers

Which of the following statements about the embryology of the Bilateria clade is correct?

They are divided into Protostomia and Deuterostomia based on embryology. Signup and view all the answers

Study Notes

Kingdom Animalia

Kingdom Animalia is divided into two groups: Parazoa (animals lacking tissues) and Eumetazoa (true animals with differentiated tissues)
Both groups likely evolved from a common ancestor that resembled modern-day choanoflagellates

Phylum Porifera - Sponges

Sponges are the simplest of all animals
They are aquatic, asymmetrical, and lack true tissues
Adults are sessile, but larvae have motility
Features:
- Osculum: opening for water expulsion
- Spongocoel: central cavity
- Choanocytes: collar cells that direct water through the sponge to trap and ingest food via phagocytosis
- Spicules: skeletal spikes of silica
Lack digestive, respiratory, circulatory, reproductive, or nervous system
Reproduction:
- Asexual: fragmentation or budding
- Sexual: differentiation of amboecytes; monoecious/hermaphroditic

Animal Phylogeny

Eumetazoa are divided into two major groups based on embryology:
- Radiata: radial symmetry (includes Cnidaria and Ctenophora)
- Bilateria: bilateral symmetry (includes all other animals)

Phylum Ctenophora

Comb jellies
Eumetazoa, radiata
Features:
- Diploblastic
- Lack cnidocytes
- Complete gut: mouth and anus

Phylum Cnidaria

Stinging animals
Eumetazoa, radiata
Features:
- Diploblastic
- Endoderm: lines digestive cavity
- Ectoderm: epidermis
- Primitive nervous system: nerve net
- Incomplete digestive system: gastrovascular cavity
- Cnidocytes: specialized cell type for stinging; contain nematocysts
Reproduction:
- Asexual: budding
- Sexual: release of gametes into the water
Carnivorous
Body plans:
- Polyp: sessile, asexual
- Medusa: dimorphic, sexual
Class names:
- Anthozoa: corals, sea anemones; polypoid
- Scyphozoa: marine jellies; medusa
- Cubozoa: box jellyfish; true eyes
- Hydrozoa: both polyp and medusa forms

Animal Phylogeny (continued)

Bilateria are divided into two major clades, also based on embryology:
- Protostomes: further divided into two major clades
  - Lophotrochozoa: either have a trochophore larva and/or lophophore (feeding structure)
  - Ecdysozoa: molt their exoskeleton (ecdysis); include Arthropoda and Nematoda
- Deuterostomes: include echinoderms and chordates

Phylum Acoela

Eumetazoa, bilateria
Features:
- Triploblastic
- Not a protostome or deuterostome
- Blastopore closes during development
- Simple nervous system differs from Platyhelminthes
- Nerve net
- Lack digestive tract: absorbs nutrients across surface
- Embryonic development is unique: one cell divides into two cells each of which then divide into more cells
- Very slight cephalization

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Description

Learn about the characteristics and classification of sponges in the Phylum Porifera, which are part of the Kingdom Animalia. Explore their simple structure, aquatic habitat, and unique features such as choanocytes and spongocoel.