chapter 32: an overview of animal diversity Flashcards
What are tissues?
groups of cells that act as a functional unit
What are the cell structure and specialization of animal cells?
- multicellular eukaryotes
- lack cell walls
- bodies held by collagen
- unique nervous and muscle tissues
What is cleavage?
the zygote undergoing rapid cell division after a sperm fertilizes an egg
What is the sequence of reproduction and development of animals?
- zygote undergoes rapid cell division called cleavage
- this leads to formation of a multicellular, hollow blastula
- blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues
What is a larva?
sexually immature and morphologically distinct from the adult
What does the larva undergo to become a juvenile?
metamorphosis
What traits do bilaterians have?
- bilaterally symmetric form
- complete digestive tract
- one-way digestive system
What is radial symmetry?
no front and back, or left/right
What do bilaterally symmetrical animals have?
- a dorsal (top)
- a ventral (bottom)
- right and left
- anterior/posterior
What is the difference between movement for radial animals and bilateral animals?
- radial animals are often sessile or planktonic
- bilateral animals often move actively as they have a central nervous system
What is the ectoderm?
the germ layer covering the embryos surface
What is the endoderm?
the innermost germ layer and lines the developing digestive tube
What are diploblastic animals?
animals that have ectoderm and endoderm
What are triploblastic animals?
have intervening mesoderm layer, all bilaterians (flatworms, vertebrates)
What is a body cavity derived from?
Its called a coelom and is derived by a mesoderm
