bio 1007 animal evolution 1

True Tissues

Groups of one or more types of cells working together to perform a specific function.

Primary role of ectoderm in animal development

It gives rise to the epidermis.

Germ layer responsible for digestive tract and organs

Endoderm

Mesoderm germ layer derivatives

Muscles, circulatory system, excretory system, and gonads.

Ecdysis

Shedding or molting of an exoskeleton for growth.

Cuticle

External structure outside the epidermis that forms the exoskeleton in many invertebrates.

Phylum Porifera (Sponges)

No true tissues, no organs, and asymmetrical body plan.

Porifera nutrient acquisition

Filter feeding.

Cnidaria body plans

Polyp (sessile, cylindrical) and medusa (free-floating).

Cnidocytes

Specialized stinging cells used for hunting in cnidarians.

Cnidarian digestive system

Gastrovascular cavity with a single opening (mouth).

Cnidarian tissue layers

Epidermis and gastrodermis.

Rotifera body cavity

Pseudocoelom.

Rotifera locomotion and feeding mechanism

Cilia.

Mollusca visceral mass

Contains most of the internal organs.

Mollusk mantle

Body wall extension that covers the visceral mass.

Mollusk shell composition

Calcium carbonate (CaCO3).

Mollusca radula

Specialized feeding structure.

Phylum Nematoda

Roundworms with pseudocoelom and proteinaceous cuticle.

Nematode vs arthropod cuticle

Protein-based cuticle vs chitin-based exoskeleton.

Segmentation in animal phyla

Annelids and Chordates.

Ecdysozoa defining trait

Shedding cuticle/exoskeleton (ecdysis).

Sponges (cell organization)

TRUE - colonies of cells that can reorganize.

Cnidarian nervous system

Nerve net (no brain).

Digestive system comparison (Rotifers/Nematodes vs Cnidarians)

Rotifers and nematodes have a complete digestive tract; cnidarians have a single opening (mouth only).