Chaptern32 — sponges Flashcards
Animal defining traits:
Multicellular eukaryotes
Heterotrophic
structural protein (rather than cell walls)
nervous and muscle tissue
Groups of similar cells that act as a functional unit
Tissues
Characteristics of animal reproduction
mostly sexual
Diploid stage dominate
Sperm and egg cells are produced by meiotic divisions
Succession of cell division with out growth between divisions
Cleavage
Blastula
Result of cleavage
- often in form of a hollow ball of cells
Bastula undergoes ______
Gastrulation
Process that forms a gastrula with different layers of embryonic tissues
Gastrulation
Characteristics of larva:
Sexually immature
Morphologically and behaviorally distinct from adult stage
Process in which larvae become juveniles
Metamorphosis
Unique family of regulatory genes
– control the expression of many other genes that influence morphology
Hox genes
Closest living relatives to modern animals
Choanoflagellates
fossils classified as (or closely related to):
Mollusks
Sponges
Cnidarians
Ediacaran Fossils
Parts arranged on a single axis
Ex: most cnidarians, jellyfish, sea anemone
Radial symmetry
Parts arranged around two axes
Ex: people, owl, lobster
Bilateral symmetry
Characteristics of bilaterians
Bilaterally symmetric form
Complete digestive tract
Digestive system with mouth and anus at opposite ends