Biodiversity of Animals Lecture Notes

A comprehensive set of vocabulary flashcards covering the biodiversity of animals, body plans, germ layers, and the ecological roles of invertebrates based on the lecture transcript.

Phylogenetic tree

A diagram showing the evolutionary relationship between ancestral groups, or organisms and their descendants.

Phylum

Taxonomic rank that falls below kingdom and above class, and which is further divided into phyla.

Taxonomist

Biologists who identify and group organisms according to their characteristics.

Invertebrates

Organisms without a backbone.

Vertebrates

Animals with a backbone.

Spicule (sponge needle)

Small structure with a sharp point in large quantities that protects and supports the sponge.

Nematocyst (nettle cell)

Specialized cell in tentacles of jellyfish that contains coiled sting / poisonous thread (is ejected as defense / to catch prey).

Mesoglea

Acellular, jelly-like tissue that functions as a hydrostatic skeleton in jellyfish, found between the ectoderm and endoderm.

Acellular

Does not consist of cells / contains no cells.

Hemocoel

Body cavity of most Invertebrates that contains circulating fluid.

Exoskeleton

Thick + rigid + outer covering that protects and supports bodies and provides a place where muscles can attach.

Molting

Process during which the outer cuticle / skin of arthropods is shed.

Body Plans

The set characteristics (shape + structure) of an animal's body that help classify animals into groups.

Cephalization

The presence of a well-developed head containing sensory organs in animals (first seen in Plathyhelminthes).

Sessile

Organisms that are immobile and spend their whole life attached to one place, e.g. Sea sponges and duck mussels.

Asymmetry

Animals that show no symmetry e.g. Sponges.

Radial symmetry

Symmetry where an animal can be cut vertically through the midline by more than 1 plane to get 2 mirror images, having definitive aboral and oral sides but no left/right side.

Bilateral symmetry

Symmetry where an animal can only be cut in 1 vertical plane by the center line, resulting in definite dorsal (top), ventral (bottom), left, right, front, and back sides.

Ectoderm

The outside germ layer of a developing embryo which gives origin to the outer protective layer, nervous system, and sensory organs.

Endoderm

The inside germ layer of a developing embryo which gives origin to the epithelial lining of the GI tract.

Mesoderm

The middle germ layer of a developing embryo which gives origin to internal organs such as the blood system, muscular system, reproduction, skeleton, and connective tissue.

Diploblastic

An embryo with 2 germ layers (ectoderm and endoderm) separated by a jelly layer (mesoglea), having only tissue and no organs.

Triploblastic

An embryo with 3 germ layers (ectoderm, mesoderm, and endoderm) that contains organs.

Coelom

An internal fluid-filled space that develops within the mesoderm and separates the GI tract from the body wall.

Acoelomates

Triploblastic animals with no coelom or space in the mesoderm.

Pseudo-coelomate

Animals where the coelom is not seen and is not surrounded by mesoderm.

Coelomates

Animals that have a space within the mesoderm.

Gastrovascular cavity

A digestive system with only one opening where food and waste pass through the same point, limiting food consumption.

Cnidoblasts (or nematocytes)

Cells in Nettle animals (Cnidaria) that contain stinging organelles called nematocysts.

Notochord

A rod-like support (spinal cord) in all Chordata which can develop into the vertebral column.

Exothermic

Animals whose body temperature is regulated by their external environment.

Endothermic

Animals whose body temperature is regulated by internal metabolic reactions, such as humans and birds.

Detritus

Organic material produced by decomposition of dead organisms.

Humus

Organic component of soil formed by decomposition of leaves by soil organisms, significantly improving soil quality.

Aeration

Process during which compacted soil is loosened or penetrated to allow air and water to pass through.

Pollination

The transfer of pollen from the anther of a flower to the stigma of a flower on the same plant by a pollinator, leading to fertilization.

Dissolution

Process where organic molecules from dead organisms are decomposed or broken down into simpler organic molecules for reuse in nutrient cycles.