Introduction to Animals

These flashcards cover key vocabulary and concepts from the lecture on animals, focusing on their structure, classification, and evolutionary significance.

Multicellular eukaryotic heterotrophs

Organisms composed of multiple cells that are eukaryotic and obtain their food by ingestion.

Chemoheterotrophs

Organisms that obtain energy and carbon by ingesting organic compounds.

Hox genes

Homeotic genes containing homeobox sequences that regulate the development of body structures in animals.

Cambrian explosion

A period (535 to 525 million years ago) marked by the rapid appearance of many major groups of animals.

Diploblastic

An organism with two embryonic tissue layers: ectoderm and endoderm.

Radial symmetry

A body plan in which body parts are arranged around a central axis.

Bilateral symmetry

A body plan with a single plane of symmetry that divides the body into equal left and right halves.

Nematocyst

A specialized cell in cnidarians that contains a stinging structure used for capturing prey.

Porifera

A phylum of animals that includes sponges, characterized by the lack of true tissues.

Cnidaria

A phylum that includes animals such as jellyfish and corals, characterized by the presence of cnidocytes.

Choanoflagellates

Single-celled organisms that are considered the closest living relatives of animals.