Animal Development Flashcards
What is fertilisation?
The bringing together of the haploid nuclei and sperm to form a diploid zygote
What is an acrosomal reaction?
Where the front of the sperm releases hydrolytic enzymes, upon meeting the egg, that depolarises the egg membrane that blocks other sperm from coming through the egg
What is a cortical reaction?
When depolarisation of the egg surface is caused, at the egg & sperm fusion, by cortical granules, which blocks polyspermy
What are the stages of embryonic development?
Cleavage -> morula -> Blastula (implantation) -> gastrulation -> beginning of development of alimentary canals -> organogenesis, organ development
What is holoblastic cleavage?
No fat cleavage (like in humans)
What is meroblastic cleavage?
Fat cleavage (like in reptiles and birds)
What are the 3 layers in germ cells?
Ectotherm, mesoderm and endoderm
What is morphogenesis?
The process of an animal taking shape
What are cadherins?
A class of cell-to-cell adhesion molecule
What are the two theories as to how siamese/conjoined twins are created?
Fission (when the fertilised egg splits partially) & fusion (fertilised egg completely separates but stem cells find like-stem cells and fuse the eggs together)
