Animal Development Quiz Flashcards
What are the five stages of development?
- Fertilization
- Cleavage
- Blastulation
- Gastrulation
- Neurulation
- Organogenesis
What are the two types of yolk distribution?
vegetal pole and animal pole
What is vegetal pole?
end of egg where most yolk is concentrated
What is animal pole?
end of egg where the least yolk is concentrated, cells divide more rapidly here
What are the two types of cleavage?
holoblastic and meroblastic
What is a holoblastic cleavage?
the whole zygote divides, low amount of yolk, ex sea star, mollusks, and flatworms
What is a meroblastic cleavage?
part of zygote divides, high amount of yolk, ex. fish, reptiles, birds
What are the two stages of blastulation?
morula and blastula
How many cells are in a morula?
16-32 cells
How many cells are in a blastula?
64 cells
What is a blastula?
a hollow sphere of cells, same size as zygote, and center cavity=blasocoel
What are the two types of egg?
isolecithal and telolecithal
What is a isolecithal egg?
small amounts of yolk, evenly distributed, ex. sea star
What is a telolecithal egg?
large amount of yolk, concentrated at one end, ex. chicken and frog
Why do cells divide more rapidly at the animal pole?
because the yolk does not divide, cells divide around the yolk, which there is more space for that to occur at the end with less yolk (animal pole)
What occurs during gastrulation?
migration and specialization of cells, blastula–> gastrula, formation of germ layers, archenteron forms, multi-layered embryo
What is a archenteron?
primitive gut, which opens to the outside via blastopore
What is a protostomes?
the archenteron eventually becomes the mouth of the organism
What is a deuterostomes?
the archenteron eventually becomes the anus of the organism
What occurs during neurulation?
chordates only, neural plate forms from ectoderm, forms neurula (development of notochord, neural tube, and coelom), neural tube becomes CNS
What are the three germ layers?
endoderm, mesoderm, ectoderm
What is the endoderm?
(inside) intestine, esophagus
What is the mesoderm?
(middle) muscle, heart
What is the ectoderm?
(outside) skin, nervous system
What occurs during organogenesis?
development of organs and shapes the organism
What five anatomical terms do we need to know for the chicken embryo?
geminal disc (becomes the chicken), yolk (feeds the chicken), chalaza (holds the yolk in equilibrium), vitelline membrane (holds yolk together), and thick and thin albumen
Characteristics of organogenesis:
48 hour or 96 hour, the brain, eye, ear, heart, somites, and vitelline blood vessels can be identified
Characteristics of neuralation:
24 hour, the brain, somites, neural tube, and primitive streak can be identified
