Animal Diversity Lecture Review

Flashcards on Animal Diversity

Animal

A chemoheterotroph organism.

Tissues

Collections of specialized cells isolated by membranes.

Organs

Collection of tissues that together provide a specific function.

Organ Systems

Several organs that work together to perform a specific function.

Choanoflagellates

Protists that are the closest living relatives of animals; animals may have evolved from a colonial protist ancestor similar to these.

Invertebrates

Animals without a backbone.

Vertebrates

Animals with a backbone.

Radial Symmetry

Symmetry around a central axis.

Bilateral Symmetry

Having a right and left side, dorsal and ventral sides, and anterior and posterior ends.

Ectoderm

The germ layer covering the embryo’s surface.

Endoderm

The innermost germ layer that lines the developing digestive tube (archenteron).

Diploblastic

Animals having only ectoderm and endoderm.

Triploblastic

Animals having ectoderm, endoderm, and mesoderm.

Coelom

A body cavity that is a space between the gut lining and the body wall fully lined with mesoderm.

Hemocoel / Pseudocoelom

A body cavity without a mesoderm-derived layer surrounding the gut lining, found in animals with open circulatory systems.

Acoelomate

Triploblastic animals with no body cavity, having a solid tissue layer derived from mesoderm between the gut lining and body wall.

Gastrovascular Cavity

A digestive cavity with a single opening.

Alimentary Canal

A digestive tube with two openings (a mouth and an anus)

Protostome

An animal in which the blastopore becomes the mouth during early embryonic development.

Deuterostome

An animal in which the blastopore becomes the anus during early embryonic development.

Hydrostatic Skeleton

Flexible support provided by fluid under pressure in a body compartment.

Exoskeleton

A rigid external support structure.

Endoskeleton

A rigid internal support structure.

Porifera

Sponges; aquatic habitat, filter feeders.

Cnidaria

Jellies, hydra, anemones, corals; aquatic habitat, polyp or medusa forms, cnidocytes for defense/feeding.

Platyhelminthes

Flatworms: tape worms, flukes, planaria; free living aquatic or parasites; simple organ systems.

Nematoda

Roundworms: nematodes; free-living terrestrial/aquatic or parasites; no circulatory system.

Annelida

Segmented worms: leeches, earthworms, polychaetes; aquatic and terrestrial habitats; closed circulatory system; body segmentation.

Mollusca

Molluscs: snails, slugs, bivalves, chiton, octopus, squid etc.; mostly aquatic, some terrestrial habitats; circulatory system open (most) or closed (cephalopods); three main body parts: muscular foot, visceral mass, mantle.

Arthropoda

Arthropods: insects, crustaceans, spiders, ticks, centipedes, etc.; aquatic and terrestrial habitats; jointed appendages; segmented bodies; open circulatory system.

Echinodermata

Echinoderms: sea stars, sea urchins, brittle stars, feather stars, sea cucumbers; marine habitats only; water vascular system – tube feet.

Chordata

Chordates: tunicates, lancelets, ALL vertebrates; aquatic and terrestrial habitats; closed circulatory system; have a notochord, dorsal hollow nerve cord, pharyngeal slits or clefts and a muscular post-anal tail at some point in development.

Notochord

A flexible rod providing support, present in chordate embryos and sometimes adults.

Dorsal, Hollow Nerve Cord

A nerve cord unique to chordates that develops into the brain and spinal cord.

Pharyngeal Slits or Clefts

Structures in the pharynx region of chordate embryos that may develop into gills or other structures.

Muscular, Post-Anal Tail

A tail posterior to the anus, present in chordate embryos and some adults.

Ray-finned Fish (Actinopterygii)

Bony fish with fins supported by bony rays.

Amphibia

Frogs, salamanders, caecilians; most are amphibious, conduct some gas exchange across the skin, and lay eggs without shells.

Amniotic Egg

An egg with a fluid-filled sac (amnion) that supports the embryo; characteristic of reptiles (including birds) and mammals.

Reptilia

Snakes, turtles, lizards, crocodiles; scales made of keratin, egg shell (often soft), ectothermic.

Birds

Wings & feathers, hollow bones, no teeth, egg shell – hard, endothermic.

Mammalia

Monotremes, Marsupials, Eutherians (placental); mammary glands – produce milk, hair and fat layer, specialized teeth, endothermic.