Invertebrate Zoology Lecture Notes 1

These flashcards cover key concepts from the Invertebrate Zoology lecture, focusing on definitions and important terms relevant to the course.

Invertebrate

An animal that lacks a backbone.

Metazoa

A clade that contains all animals, synonymous with Kingdom Animalia.

Choanoflagellates

Unicellular protists thought to be the closest living relatives to Metazoa.

Synapomorphies

Derived traits unique to a clade.

Deuterostomia

A major clade within the Metazoa that includes animals like echinoderms and chordates.

Ecdysozoa

A clade that includes organisms that shed their exoskeletons, like arthropods and nematodes.

Biodiversity

The variety of life in a particular habitat or ecosystem.

Differentiation-first hypothesis

A theory stating that ancestral cells differentiated at various stages in their life cycle before multicellularity.

Multicellular-first hypothesis

The traditional view that multicellularity arose from a choanoflagellate-like cell forming colonies.

Non-parsimonious clade

A clade that does not include all descendant lineages of the last shared ancestor.