INTRODUCTION TO DEVELOPMENTAL BIOLOGY 2
GASTRULATION 3
MAJOR EARLY EVENTS 1 5
MAJOR EARLY EVENTS 2 7
DEVELOPMENT AND EVOLUTION 9
CELL DIVISION AND DIFFERENTIATION 11
WEEK 1 ............................................................................................................................................................................. 2
INTRODUCTION TO DEVELOPMENTAL BIOLOGY ....................................................................................................................... 2
GASTRULATION ................................................................................................................................................................ 3
MAJOR EARLY EVENTS 1 ................................................................................................................................................... 5
MAJOR EARLY EVENTS 2 ................................................................................................................................................... 7
DEVELOPMENT AND EVOLUTION ....................................................................................................................................... 9
CELL DIVISION AND DIFFERENTIATION ............................................................................................................................. 11
, WEEK 1
INTRODUCTION TO DEVELOPMENTAL BIOLOGY
Describe the animal models used in developmental biology and their advantages and disadvantages.
Describe how cell division and cleavage occurs in the fertilised egg during the formation of the blastocyst.
Describe changes in the organisation of the blastula following implantation.
Model organisms
Invertebrates Vertebrates (anamniotes)
- Drosophila (fruit flies) - Develop external to mother
- Short life span - Large eggs
- Not vertebrate - Transparent
- Easy to handle large numbers - Easy to mutate
- Easily mutated - Sequenced genomes
- Genome sequenced
Fertilisation and formation of embryo
- 2 germ cells meet and fuse → forms zygote
- Primordial germ cells come from ovary/testis → diploid (2n)
- Germ cells → haploid (1n) through meiosis
- Entry of sperm → formation of zygote → oocyte becomes impenetrable (prevents polyspermy)
Cleavage stage
- Cells divide, becoming smaller → called blastomeres
- Each cell touches zona pellucida (outer membrane)
-
- Reorganises to create inner and outer layer of cells
- Inner core = cells form inner cell mass. Become the embryo
- Outer core = cells are trophoblasts. Become extra-embryonic membranes → placenta
Blastocyst stage
- Cells on outside pump fluid into embryo → Forms blastocyst cavity
- Now called blastula
Blastocyst hatching
- Breaks out of Zona pellucida → begins to grow
- After hatching, implantation occurs → implants in uterine wall (requires nutrients/waste excretion)
Inner cell mass
- Undergo reorganisation into 2 specific cell layer s
- Epiblast layer = makes embryonic tissues, columnar cells
- Hypoblast layer = face yolk sac, cuboidal cells
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 EFT, 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 this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller febetiki. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R469,78. You're not tied to anything after your purchase.
