Introduction to Animals (Animal Body Plan)

Flashcards based on key vocabulary and concepts from the lecture on animal body plans and classification.

Eukaryotic Supergroup

A major classification of life that includes organisms with complex cells. In animals, the relevant clade is Opisthokonts.

Multicellular Eukaryotes

Organisms composed of more than one cell that contain membrane-bound organelles and a nucleus.

Heterotrophic

Organisms that cannot produce their own food and must obtain nutrition by consuming other organisms.

Motile

The ability to move; at some stage in life, all animals are motile, although many become sessile as adults.

HOX genes

A group of related genes that control the body plan of an embryo along the anterior-posterior (head-tail) axis.

Parthenogenesis

A form of asexual reproduction in which an egg develops into an individual without fertilization.

Bilateral symmetry

A body plan in which the left and right sides of the organism are mirror images of each other.

Radial symmetry

A body plan in which body parts are arranged around a central axis; common in organisms like jellyfish and starfish.

Coelomate

An organism with a true coelom, or body cavity, fully surrounded by mesoderm tissue.

Acoelomate

An organism that lacks a body cavity; organs are embedded in solid tissue.

Archenteron

The primitive digestive cavity that develops during the early stages of embryonic development.

Cleavage

The series of rapid cell divisions that occurs after fertilization, leading to the formation of a blastula.

Gastrulation

The process during embryonic development in which the blastula reorganizes into three layers: ectoderm, mesoderm, and endoderm.

Diploblast

An organism with two germ layers: ectoderm and endoderm, without mesoderm.

Triploblast

An organism with three germ layers: ectoderm, endoderm, and mesoderm.

Phyletic gradualism

The model of evolution that proposes gradual changes in species over time rather than sudden changes.

Punctuated equilibrium

The evolutionary theory that species experience significant changes in relatively short periods, separated by long periods of stasis.