Animal development. Flashcards
What is the sequence of animal development?
- Fertilization- single cell zygote
- Cleavage- multicellular embryo
- Gastrulation- making of embryonic
- Organogenesis- making of tissue and organs
What do stem cells do.
Build or renew other cells
What is fertilization?
Implant of sperm nucleus in egg.
What is egg structure?
Large immobile part that contains embryonic nutrients.
What are the concentrated components of the egg?
Yolk, cortical granules, and maternal determinants.
What is polyspermy?
Fertilization by more than one sperm.
What is the fertilization envelope?
Physical barrier of calcium after one sperm enters the egg.
What is cleavage?
Rapid cell division but does not change size of zygote.
When individual cells are made, what are they called? What are they called in a group?
Blastomeres
Group= blastula
Types of cleavage? And what they are?
= Radial- cells divide @ right angles
= Spiral- cells divide @ oblique angles
= Discodial- small cells form on top of yolk
= Superficial- cells form on outside of yolk
What is cleavage in animals?
- Occurs in oviduct
- Specialized blastula(blastocyst)
- —trophoblast placenta
- —inner cell mass: goes thru gastrulation
What is gastrulation?
Structure of embryonic cells and body axis
What are the germ (embryonic) layers?
Endoderm- inner
Mesoderm- middle
Ectoderm- outer
What is organogenesis?
- The process organ and tissue formation.
- Cell differentiation into specific structures and functions w/ own set of genes.
What is a Notochord?
Chordate- in animals organize parts.
