Ch. 18 The Evolution of Animal Diversity Flashcards
Animalia
The kingdom that contains the animals
Blastula
An embryonic stage that marks the end of cleavage during animal development; a hallow ball of cells in many species
Gastrula
The embryonic stage resulting from gastrulation in animal development; most animals have gastrula made up of 3 layers of cells (ectoderm, endoderm, mesoderm)
Larva
An immature individual that is structurally and often ecologically very different from an adult
Metamorphosis
The transformation of a larva into an adult
From where did the animal kingdom probably originate?
Colonial protists
Invertebrate
Animal that lacks a backbone
Porifera
The phylum that contains the sponges, characterized by choanocytes, a porous body wall, and no true tissues
Sponge
Marine or freshwater, living singly or clusters by budding (regeneration)
Radial Symmetry
An arrangement of the body parts of an organism like pieces of a pie around an imaginary central axis; any slice passing longitudinally through a radially symmetrical organism’s central axis divides it into mirror-image halves
What are the 3 layers of a sponge (porifera)?
1) Flattened cells w/ pink pore
2) Amoebocytes
3) Choanocyte
Amoebocytes
An amoeba-like cell that moves by pseudopodia found in most animals; may digest and distribute food, dispose of wastes, make skeleton, fight infections, change into other cell types
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
Choanoflagellate
An ancestral colonial protist from which sponges, and possibly all animals, probably arose (bottom of ponds/shallow sea)
Cnidaria
The phylum that contains the hydras, jelly fishes, sea anemones, corals, and related animals characterized by enidocytes, radial symmetry, a gastrovascular cavity, polyps, and medusae
- can have both polyp and medusa
Polyp
One of two types of cnidarian body forms; a columnar, hydra-like body (stationary)
Medusa
One of two body types of cnidarian body forms; an umbrella-like body form aka jellyfish (free moving)
Gastrovascular cavity
A digestive compartment w/ a single opening, the mouth; may function in circulation, body support, waste disposal, gas exchange, and digestion
Cnidocytes
A specialized cell for which the phylum Cnidaria is named; consists of a capsule containing a fine thread, which, when discharged, functions in defense and prey capture
What are the 7 characteristics of an anima?
1) Eukaryotic
2) Multicellular
3) Heterotrophic
4) Lack cell walls
5) Ingestion (internal digestion)
6) Unique intercellular junctions
7) Embryonic stages (gametes -> zygote -> blastula -> gastrula)
What are the criteria of classification?
1) Symmetry
- radial or bilateral
2) Level of organization
- tissue level or organ system level
3) Embryonic Tissue
4) Body plan
- gastrovascular cavity or complete digestive system
5) Body Cavity
- pseudocoelom or coelom
Symmetry
How body parts are arranged around a median plane
Body Cavity
Fluid filled space b/w digestive tract
Pseudocoelom
A body cavity that is in direct contact with the wall of the digestive tract and muscle layer
- Lacks mesoderm