Introduction to Animal Diversity and Development

Vocabulary flashcards covering key concepts from the lecture on animal characteristics, embryonic development stages, germ layers, body plans, and protist diversity.

Heterotrophic

A nutritional mode requiring the ingestion of other living or dead organisms for survival, as opposed to autotrophic organisms that synthesize their own nutrients.

Collagen

A structural protein that supports animal cells by providing structure and rigidity and connecting cells to one another in the absence of a cell wall.

Cleavage

A series of rapid cell divisions undergone by a zygote after fertilization during which the cell membrane pinches in without an increase in cell mass.

Blastula

An embryonic stage occurring at around 100 cells, consisting of a hollow, spherical layer of cells surrounding a fluid-filled or yolk-filled cavity called a blastocoel.

Blastocoel

The fluid-filled or yolk-filled cavity enclosed by the spherical layer of cells within a blastula.

Gastrulation

The embryonic process in which the blastula invaginates (folds in on itself) to form distinct germ layers that develop into all body tissues and organs.

Blastopore

The initial opening or invagination formed during gastrulation that eventually develops into either the mouth or the anus depending on the animal lineage.

Ectoderm

The outermost embryonic germ layer covering the embryo surface that gives rise to the skin (integumentary layer) and parts of the nervous system.

Mesoderm

The middle embryonic germ layer that gives rise to muscle tissues, skeletal structures, and the circulatory system.

Endoderm

The innermost embryonic germ layer that forms the lining of the digestive tube, digestive organs, and lungs.

Triploblastic

Refers to animals whose embryos develop all three germ layers: ectoderm, mesoderm, and endoderm.

Diploblastic

Refers to animals, such as cnidarians, that develop only two germ layers (ectoderm and endoderm) and lack a mesoderm.

Coelum

A true body cavity consisting of a fluid-filled space fully lined with mesodermal epithelium.

Pseudocoelamates

Animals that possess a body cavity that is not completely lined by mesodermal cells.

Acoelomates

Animals that lack a body cavity altogether and have solid tissue between the digestive tract and outer body wall.

Radial Body Symmetry

A body plan arranged around a central axis, allowing the organism to be divided into mirror-image halves across multiple planes.

Bilateral Symmetry

A body plan that divides an animal along a single sagittal plane into mirror-image left and right halves, featuring distinct dorsal, ventral, anterior, and posterior ends.

Protostome Development

A developmental mode characterized by spiral and determinate early cleavage, where the blastopore ultimately becomes the mouth.

Deuterostome Development

A developmental mode characterized by radial and indeterminate early cleavage, where the blastopore ultimately becomes the anus.

Morula

A solid circular ball of cells formed by repeated divisions of the fertilized egg cell before developing into a blastula.

Mixotrophs

Organisms that normally perform photosynthesis to generate energy but can supplement their nutrition by consuming other organisms when light levels are low.

Pseudopodium

A temporary extension of cytoplasm ("false foot") used by amoeboid protists for locomotion and prey ingestion via changes in cytoplasmic viscosity.