animals

Animals

Multicellular, heterotrophic organisms that usually can move.

Asymmetrical

No symmetry, characteristic of sponges.

Radial Symmetry

Multiple mirror-image planes around a central axis, found in cnidarians.

Bilateral Symmetry

One plane divides the body into left and right halves, seen in flatworms and humans.

Monoblastic

Organisms with one germ layer, such as sponges.

Diploblastic

Organisms with two germ layers, ectoderm and endoderm, like cnidarians.

Triploblastic

Organisms with three germ layers, ectoderm, mesoderm, and endoderm, such as flatworms.

Choanocytes

Collar cells in sponges that trap food particles.

Cnidocytes

Special cells in cnidarians that contain nematocysts for stinging prey.

Gastrovascular cavity

A digestive system with one opening, found in cnidarians.

Acoelomate

Animals with no body cavity, like flatworms.

Pseudocoelomate

Animals with a body cavity not fully lined with mesoderm, such as roundworms.

Coelomate

Animals with a true coelom, like segmented worms.

Exoskeleton

A hard outer structure that provides support and protection in arthropods.

Deuterostomes

Organisms in which the blastopore becomes the anus, including echinoderms and chordates.

Homologous structures

Body parts that share the same origin but have different functions.

Analogous structures

Body parts that serve similar functions but evolved separately.

Vertebrates

Animals with backbones, including fish, amphibians, reptiles, birds, and mammals.

Phylum Porifera

The phylum that includes sponges.

Phylum Cnidaria

The phylum that includes jellyfish, hydras, and sea anemones.

Phylum Platyhelminthes

The phylum that includes flatworms like planaria and tapeworms.

Phylum Nematoda

The phylum that includes roundworms.

Phylum Annelida

The phylum that includes segmented worms, such as earthworms.

Phylum Mollusca

The phylum that includes clams, snails, and squids.

Phylum Arthropoda

The phylum that includes insects, crustaceans, spiders, and centipedes.

Chordates

Animals in the phylum that define four key characteristics: dorsal nerve cord, notochord, pharyngeal slits, and post-anal tail.