Intro to animals

Multicellularity

All animals are composed of multiple cells.

Heterotrophs

Organisms that obtain food by consuming other organisms.

Nervous Tissue

Tissue that enables rapid response to environmental stimuli.

Movement

Most animals can move, facilitated by muscles and a nervous system.

Sexual Reproduction

Most animals reproduce sexually, involving the fusion of gametes.

Extracellular matrix

A structure that binds animal cells together.

Hox Genes

Genes that determine body axis and segmental organization.

Blastula

A hollow ball of cells formed during early embryonic development.

Gastrulation

The process where the blastula develops into a gastrula with three germ layers.

Coelom

A fluid-filled body cavity that allows for greater organ complexity.

Acoelomate

An organism lacking a coelom, filled with tissue instead.

Diploblast

An organism with two germ layers: ectoderm and endoderm.

Triploblast

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

Protostome

An organism where the blastopore becomes the mouth.

Deuterostome

An organism where the blastopore becomes the anus.

Germ Layer

A primary layer of cells that gives rise to specific tissues.

Radial Symmetry

Symmetry where body parts radiate from a central point.

Bilateral Symmetry

Symmetry where the body can be divided into right and left halves.

Cephalization

The development of a head with sensory organs in bilateral animals.

Parthenogenesis

A form of asexual reproduction where unfertilized eggs develop into individuals.

Oviparous

Organisms that lay eggs.

Viviparous

Organisms that give birth to live young.

Cleavage

The series of mitotic divisions of a zygote after fertilization.

Cambrian Explosion

A rapid diversification of animal life that occurred approximately 541 million years ago.

Ecdysozoa

A group of protostomes that shed their exoskeleton.

Lophotrochozoa

A group of protostomes characterized by a lophophore or trochophore larva.

Eumetazoa

Animals with specialized tissues.

Parazoa

Animals lacking true tissues, such as sponges.

Nerve net

A diffuse network of neurons seen in radially symmetrical animals.