Class notes
Biol 105 Chapter 42 Notes
- Course
- Bio 105
- Institution
- Queens College
This is a comprehensive and detailed note on Chapter 42; Animal development for Biol 105. *Essential Study material!! *For you, at a price that's worth it!!
[Show more]
Seller
Follow
Content preview
Chapter 42:Animal Development
Key Steps in Embryogenesis
● Establishment of axes: dorsal-ventral, anterior-posterior, left-right.
● Production of large numbers of pluripotent cells: cleavage. •
● Arrangement of pluripotent cells into tissue layers that resemble an
organism: gastrulation.
● Organogenesis: neurulation, cardiogenesis, etc.
● Establishment of body segments: somitogenesis
Development
● The process in which a multicellular organism undergoes a series of
progressive changes that characterize its life cycle.
Processes underlying development
● determination — sets the fate of cells (i.e., what they will become), prior
to the emergence of type-specific characteristics.
● differentiation — the process by which structurally and functionally
distinct cell types arise
● morphogenesis — organization and arrangement of cells.
● growth — increase in the size of body and organs via cell division, cell
expansion.
○ (Lots of different model systems used for developmental studies.)
● Cells in the early embryo arise from repeated mitosis and soon begin to
differ in terms of which genes are expressed.
● Determination and differentiation occur largely because of differential
gene expression.
Fertilization Initiates Development
● Dorsal-ventral (DV) axis is determined by point of sperm entry
● Sperm enters the animal hemisphere—rotation of cortical cytoplasm
toward the site of entry establishes dorsal ventral axis.
● Site of sperm entry becomes the ventral region; the gray crescent (a
band of pigmented cytoplasm opposite the site of sperm entry, visible in
some amphibian species) becomes the dorsal region of embryo. How?
, ● ● Beta Catenin (yellow)
● GSK3 (blue)
● Vesicles with GSK inhibitor
(red)
→ Cleavage Types
Complete Cleavage
● In relatively small eggs, or eggs with a relatively small amount of yolk,
the entire egg is divided
Incomplete Cleavage
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anyiamgeorge19. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72964 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now