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Evolution of Biological Diversity: Section 18.1-18.7

Terms in this set (44)

Ingestion
The act of eating; the first main stage of food processing in animals.
Blastula
An embryonic stage that marks the end of cleavage during animal development; a hollow ball of cells in many species.
Gastrula
The embryonic stage resulting from gastrulation in animal development. Most animals have a gastrula made up of three layers of cells: ectoderm, endoderm, and mesoderm.
Endoderm
The innermost of 3 embryonic cell layers in a gastrula; forms the archenteror in the gastrula and gives rise to the innermost lining of the digestive tract and other hollow organs in the adult.
Ectoderm
The outer layer of 3 embryonic cell layers in a gastrula; forms the skin of the gastrula and gives rise to the epidermis and nervous system in the adult.
Mesoderm
The middle of the three embryonic cell layers in a gastrula; gives rise to muscle, bones, the dermis of the skin, and most other organs in the adult.
Larva
A free-living, sexually immature form in some animal life cycles that may differ from the adult in morphology, nutrition, and habitat.
Metamorphosis
The transformation of a larva into an adult.
Cambrian explosion
Time period about 542 millions years ago in which fossil records marked a dramatic increase in animal diversity.
Invertebrates
An invertebrate that lacks a backbone.
Radial Symmetry
An arrangement of the body parts of an organism like part of a pie around an imaginary central axis. Any slice passing longitudinally through a radially symmetrical organism's central axis divides it into mirrors image halves
Bilateral Symmetry
An arrangement of body parts such that an organism can be divided equally by a single cut passing longitudinally through it. A bilaterally symmetrical organism has mirror-image right and left sides.
Body Cavity
A fluid-containing space between the digestive tract and the body wall.
Hydrostatic Skeleton
A skeletal system composed of fluid held under pressure in a closed body compartment; the main skeleton of most cnidarians, flatworms, nematodes, and annelids.
Pseudocoelom
A body cavity that is in direct contact with the wall of the digestive tract.
Coelom
A body cavity completely lined with mesoderm
Protostomes
An animal with coelom that develops from solid masses of cells that arise between the digestive tube and the body wall of the embryo. The protostomes include the molluscs, annelids, and arthropods.
Deuterostomes
An animal with a coelom that forms from hollow outgrowths of the digestive tube of the early embryo. The deuterostomes include the echinoderms and the chordates.
Eumetazoans
Member of the clade of "true animals," the animals with true tissues (all animals except sponges).
Bilaterians
Member of the clade of animals with bilateria exhibiting bilateral symmetry.
Sponges
An aquatic animal characterized by a highly porous body.
Choanocytes
A flagellated feeding cell found in sponges. Also called a collar cell, it has a collar-like ring that traps food particles around the base of its flagellum.
Amoebocytes
An amoeba-like cell that moves by pseudopodia, found in most animals; depending on the species, may digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.
Suspension feeders
An animal that extracts food particles suspended in the surrounding water.
Cnidarians
An animal characterized by cnidocytes, radial symmetry, gastrovascular cavity, and a polyp and medusa body form. Cnidarians include hydra, jellyfishes, sea anemones, corals, and related animals.
Polyp
One of two types of cnidarian body forms; a columnar, hydra-like body.
Sessile
An organism that is anchored to its substrate.
Medusa
One of two types of cnidarian body forms; an umbrella-like body form. Also called a jellyfish.
Gastrovascular cavity
A digestive compartment with a single opening, the mouth; may function in circulation, body support, waste disposal, and gas exchange, as well as digestion.
Cnidocytes
A specialized cell for which the phylum Cnidaria is named; consists of a capsule containing a fine coiled thread, which, when discharged, functions in defense and prey capture.
Flatworms
A member of the phylum Platyhelminthes.
Free living flatworms
One of a group of non parasitic flatworms
Flukes
One of a group of parasitic flatworms.
Tapeworms
A parasitic flatworm characterized by the absence of a digestive tract.
Anatomy
the branch of science concerned with the bodily structure of humans, animals, and other living organisms, especially as revealed by dissection and the separation of parts.
Physiology
the branch of biology that deals with the normal functions of living organisms and their parts.
Anterior (Ventral)
Towards the front of the body
Posterior (Dorsal)
Towards the back of the body
Medial
Towards the middle of the body
Lateral
Towards the outside of the body
Superior
Towards the head on a human
Inferior
Towards the feet on a human
Proximal
Towards the body on a limb
Distal
Towards the end of a limb
THIS SET IS OFTEN IN FOLDERS WITH...