Protostome Flashcards

Vocabulary flashcards for Protostome lecture review.

Protostomes

A major group of animals.

Molecular Phylogenies

Support the hypothesis that protostomes are a monophyletic group.

Lophotrochozoa

A major subgroup of protostomes.

Ecdysozoa

A major subgroup of protostomes.

Mollusca

A diverse and species-rich lineage of protostomes.

Arthropoda

A diverse and species-rich lineage of protostomes.

Key events in protostome diversification

Water-to-land transition, diversification of appendages and mouth parts, and evolution of metamorphosis.

Arthropods

Include insects, spiders, and crustaceans.

Molluscs

Include snails, clams, octopuses, and squids.

Protostomes

Most animals are protostomes.

Cleavage

Zygote undergoes rapid divisions, eventually forming a mass of cells.

Spiral cleavage

A characteristic of protostome cleavage.

Gastrulation

Mass of cells is rearranged to form gut and embryonic tissue layers.

Coelom formation

Body cavity lined with mesoderm develops.

Mesoderm

Tissue layer involved in coelom formation.

Insects

A major protostome phylum.

Nematoda

A major protostome phylum.

Annelida

A major protostome phylum.

Platyhelminthes

A major protostome phylum.

Mollusca

A major protostome phylum.

Arthropoda

A major protostome phylum.

Protostome characteristics

Bilaterally symmetric, triploblastic, coelomate animals.

Monophyletic group

Protostomes are a monophyletic group.

Lophotrochozoa and Ecdysozoa

Two major lineages of protostomes.

Protostome development

Pattern of development that distinguishes protostomes.

Bilateral symmetry

A key characteristic of protostomes.

Triploblasty

A key characteristic of protostomes.

Coelom

A key characteristic of protostomes.

Number of protostome phyla

There are 22 phyla of protostomes.

Pseudocoelom

A body cavity type found in some protostomes.

Porifera

Phylum containing sponges; a non-protostome phylum.

Cnidaria

Phylum containing jellyfish and corals; a non-protostome phylum.

Chordata

Phylum containing vertebrates; a non-protostome phylum.

Echinodermata

Phylum containing sea stars; a non-protostome phylum.

Rotifera

Phylum containing rotifers; a protostome phylum (Lophotrochozoa).

Platyhelminthes

Phylum containing flatworms; a protostome phylum (Lophotrochozoa).

Annelida

Phylum containing segmented worms; a protostome phylum (Lophotrochozoa).

Mollusca

Phylum containing molluscs; a protostome phylum (Lophotrochozoa).

Nematoda

Phylum containing roundworms; a protostome phylum (Ecdysozoa).

Arthropoda

Phylum containing arthropods; a protostome phylum (Ecdysozoa).

Ectoprocta

Phylum containing ectoprocts

Chaetognatha

Phylum containing arrow worms

Nemertea

Phylum containing ribbon worms

Gastrotricha

Phylum containing gastrotrichs

Acanthocephala

Phylum containing acanthocephalans

Entoprocta

Phylum containing entroprocts

Gnathostomulida

Phylum containing gnathostomulids

Sipuncula

Phylum containing peanut worms

Echiura

Phylum containing spoon worms

Phoronida

Phylum containing horseshoe worms

Brachiopoda

Phylum containing brachiopods

Kinorhyncha

Phylum containing kinorhynchs

Nematomorpha

Phylum containing hair worms

Priapula

Phylum containing priapulans

Onychophora

Phylum containing velvet worms

Tardigrada

Phylum containing water bears

Hemichordata

Phylum containing acorn worms

Lophotrochozoan

A major group of protostomes.

Lophotrochozoans

Highly diverse in morphology.

Lophophore

A feeding structure in some lophotrochozoans.

Trochophore

A type of larva common to several phyla of lophotrochozoa.

Suspension feeding

Lophophores function in what in adults?

Ecdysozoan

A major group of protostomes.

Molting

Shedding of the soft cuticle or hard exoskeleton by ecdysozoans.

Cuticle

Protective outer layer in ecdysozoans.

Exoskeleton

Protective outer layer in ecdysozoans.

Nematoda

Roundworms; a prominent ecdysozoan phylum.

Arthropoda

Arthropods; a prominent ecdysozoan phylum.

Protostome diversification

Triggered by evolutionary innovations in body plan, feeding, moving, and reproducing.

Basic body plan of protostomes

Wormlike bodies with a basic tube-within-a-tube design.

Tube-within-a-tube design

Body wall derived from ectoderm, muscles and organs from mesoderm, gut from endoderm.

Coelom formation

Radical changes occurred in what as protostomes diversified?

Platyhelminthes

Flatworms; are acoelomate, lacking a body cavity.

Acoelomate

Lacking a body cavity.

Pseudocoelom

Forms from an opening between the ectoderm and mesoderm.

Arthropoda and Mollusca

The coelom is drastically reduced in these phyla.

Functions of a coelom

Providing space for fluids to circulate, and providing a hydrostatic skeleton.

Arthropod body plan

Segmented bodies organized into head, thorax, and abdomen.

Arthropod characteristics

Jointed limbs and an exoskeleton made of chitin.

Hemocoel

Spacious body cavity in arthropods.

Tagma

Prominent regions of arthropod body.

Chitin

Material that makes up the exoskeleton of arthropods.

Molluscan body plan

Based on the foot, visceral mass, and mantle.

Foot

Large muscle located at the base of the animal and usually used in movement (Molluscs).

Visceral mass

Region containing most of the internal organs and external gill (Molluscs).

Mantle

Tissue layer that covers the visceral mass and secretes a shell in some species (Molluscs).

Water-to-Land transition

Evolved independently in arthropods, molluscs, roundworms, and annelids.

Adaptations for land

Exchanging gases and avoiding drying out.

Protostome movement

Includes walking, running, jumping, flying, gliding, crawling, and jet propulsion.

Asexual reproduction

Common in many wormlike phyla.

Parthenogenesis

Unfertilized eggs develop into offspring.

Sexual reproduction

Starts with external fertilization in sessile forms, and internal fertilization in groups that can move.

Metamorphosis

A unique reproductive innovation during protostome diversification.

Rotifera

Rotifers; a key lophotrochozoan group.

Platyhelminthes

Flatworms; a key lophotrochozoan group.

Annelida

Segmented worms; a key lophotrochozoan group.

Mollusca

Molluscs; a key lophotrochozoan group.

Rotifers

Live in damp soils as well as marine and freshwater environments.

Corona

A cluster of cilia at the anterior end of rotifers used for suspension feeding.

Flatworms

Have a broad, flattened body shape with a large surface area for gas exchange.