Spr 2024 Week 10 Opisthokonta_ Intro to Animal Diversity_Porifera, Cnidaria

Opisthokonta

A major grouping within the domain Eukaryota, comprising animals, fungi, and related forms.

Diploblastic

Animals with two germ layers in their embryos, typically the ectoderm and endoderm.

Triploblastic

Animals with three germ layers in their embryos, including the ectoderm, endoderm, and mesoderm.

Multicellularity

The state of being composed of multiple cells.

Heterotrophy

Obtaining nutrients by ingesting organic matter.

Neurons

Nerve cells that transmit electrical signals.

Muscle cells

Cells capable of contracting and enabling movement.

Radial symmetry

Symmetry around a central axis, like in a sea anemone.

Bilateral symmetry

Symmetry with a single plane dividing the body into left and right halves, as seen in a lobster.

Nervous system

The network of nerve cells responsible for transmitting signals and coordinating bodily functions.

Nerve net

A diffuse arrangement of nerve cells found in radially symmetric organisms.

Central nervous system (CNS)

A centralized arrangement of nerve cells found in bilaterally symmetric organisms.

Cephalization

The concentration of sensory organs and nervous tissues in the anterior end of an organism.

Cephalization

The development of a head region in animals where structures for feeding, sensing the environment, and processing information are concentrated.

Coelom

An enclosed, fluid-filled body cavity in animals that provides space for organs to grow, acts as a shock absorber, and aids in movement.

Pseudocoelomates

Animals with a body cavity derived from the blastocoel rather than from mesoderm.

Hydrostatic skeleton

A system in soft-bodied animals where the coelom filled with fluid helps in movement and provides support.

Protostomes

Animals where the mouth develops before the anus during embryonic development, including arthropods, mollusks, and segmented worms.

Deuterostomes

Animals where the anus develops before the mouth during embryonic development, including chordates and echinoderms.

Gastrulation

A series of cell movements during embryonic development that results in the formation of embryonic tissue layers and the coelom.

Synapomorphies

Shared derived characteristics that define a particular group.

Endoderm

The innermost germ layer that develops into the lining of the digestive tract.

Ectoderm

The outermost germ layer that develops into the skin and nervous system.

Gemmules

Asexual buds produced by amoebocytes in sponges for reproduction.

Cnidaria

A phylum of animals that are diploblasts with radial symmetry, a gastrovascular cavity, cnidocytes, and a single opening serving as both mouth and anus. Examples include hydras, sea anemones, jellies, corals, Portuguese man-of-war, and fire coral.

Radial Symmetry

Symmetry around a central axis, like spokes on a wheel.

Cnidocytes

Specialized stinging cells in cnidarians used for capturing prey.

Polyp

Cylindrical, sessile form of cnidarians that adheres to a substrate.

Medusa

Flattened, free-swimming form of cnidarians with a mouth-down orientation.

Mesoglea

Gelatinous layer sandwiched between the ectoderm and endoderm in cnidarians, providing structural support.

Nematocysts

Organelles within cnidocytes that can sting or discharge threads to capture prey.

Bilateria

A major group of animals characterized by bilateral symmetry and three germ layers.

Deuterostome

An animal group where the anus develops before the mouth during embryonic development.

Ecdysozoa

Another major protostome subgroup including arthropods and nematodes that grow by shedding their external skeletons.