Biology Chapter on Protostomes

What character differentiates Protostomes from Deuterostomes?

What percentage of animals are considered Protostomes?

Which of the following is a feature of Lophotrochozoans?

What term describes the feeding structure found in some Lophotrochozoans?

Which group lost many ancestral characters, such as a complex digestive system?

Which of the following statements is true about Annelida?

What type of body symmetry do Protostomes generally exhibit?

What type of environments can Platyhelminthes occupy?

What is a characteristic feature of organisms classified under Ecdysozoans?

Which phylum is known for having a body cavity that may be pseudocoelomate or coelomate?

In terms of biodiversity, how significant are nematodes in soil samples?

What is one of the synapomorphies of the phylum Arthropoda?

Which of the following best describes the structure of the beak in certain mollusks?

What is considered a unique feature lost in some mollusks?

Which of the following is NOT a class within the phylum Mollusca?

What type of habitat do most nematodes inhabit?

Protostomes

Protostomes are animals (except sponges, cnidarians, and ctenophores)
Distinguished from deuterostomes by characters in early embryonic development

Protostome vs. Deuterostome Characteristics

Fate of blastopore: Protostomes: mouth; Deuterostomes: anus
Cleavage: Protostomes: spiral, determinate; Deuterostomes: radial, indeterminate
Coelom formation: Protostomes: schizocoelous; Deuterostomes: enterocoelous

Lophotrochozoans

Lophophore: Feeding structure in suspension feeding adults
Trochophore: Larval stage, for swimming and feeding
Platyhelminthes (flatworms): Lost characteristics of ancestors including coelom, two-way gut, and an excretory system
- Some are free-living, others are parasitic
Annelida (segmented worms):
- Paired chaetae (bristles) extending from each body segment
- Parapodia (appendages) on each body segment
Mollusca (various):
- Shell for protection and structure
- Mantle secretes the shell
- Radula (scraper) for feeding (lost in some)
- Foot for movement (lost in some)

Ecdysozoans

Undergo ecdysis (molting of a hard exoskeleton or cuticle)
Nematoda (roundworms):
- Body cavity: pseudocoelom
- Free-living or parasitic
- Abundant in soil

Arthropoda (insects, crustaceans, etc.)

Synapomorphies:
- Exoskeleton of chitin
- Paired, jointed appendages
- Segmented bodies
- Tagmata (fused body segments)
Learning objectives:
- Phylum placement & characteristics
- Body plan features
- Development of each
- Synapomorphies
- Differences between protostomes & deuterostomes
- Major classes
- Mollusca variations
- Ecdysis & groups undergoing it
- Tagmatization vs segmentation
- Most diverse protostome class

Explore the fascinating world of protostomes in this quiz. Dive into their embryonic development and distinctive characteristics compared to deuterostomes. Discover the diverse groups of lophotrochozoans including flatworms, segmented worms, and mollusks.