Procedure
Part A: Introduction

• Answer questions in Part A of the Lab Report

Part B: Normal Development

• Answer questions 5-8 in Part B of the Lab Report.
• Use the slides provided under the "Normal Amphibian Development" section of the Lab 4 reading and on the slides below to determine the stage that each embryo is at and answer questions about each stage (or phase).
• Be sure to look back at the description and at the images on the slides in the "Normal Amphibian Development" section for help.

Fertilized frog egg containing 4 cells.
A tight ball of cells
Gastrula with a smaller mass of endodermal cells. The Letter A is pointing to the mass of endodermal cells.
A neurula in which the rising of the ectoderm first becomes obvious. B is pointing to an area near the dorsal midline where the ectoderm is raised and flattened.
Xenopus embryo at the tail bud stage during which the body has elongated more and the tail and gill plates form. C os pointing to a dark spot forming on the side of the head. D is pointing to a sucker forming on the ventral side of the head and E is pointing to a bud forming at the most posterior end of the embryo.
Image of approximately 38 eggs of which 37 show signs of having undergone cleavage divisions and one has not undergone any divisions. Most of the fertilized eggs contain 8 cells.

Part C: Environmental Affects

• Answer questions 25 & 26 in Part C of the Lab Report.
• Complete the Table below and answer the remaining questions in Part C of the Lab Report.

Table with columns for pH, number of tadpoles, number of tadpoles + eggs and percent developed (fill this column in). Row 1 pH =4, Number of tadpoles = 10, number of tadpoles + eggs = 40, fill in percent developed to answer question 27. Row 2 pH =5, Number of tadpoles = 20, number of tadpoles + eggs = 43, fill in percent developed to answer question 28. Row 3 pH =7, Number of tadpoles = 22, number of tadpoles + eggs = 23, fill in percent developed to answer question 29.

Part D: Definitions

• Use the list of words below to match them to their correct definition.

List reads; animal pole, archenteron, blastocoel, Blastopore, Blastula phase, cleavage, Dorsal lip of blastopore, gastrulation, Germ layers, gray crescent, mesolecithal egg, neural plate, neural tube, neurulation, optic cup, vegetal pole. yolk plug and zygote.


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After you have submitted your Lab Report Via Google please go to Blackboard, select the Lab for this week and the "Grading Rubric" . Then select "Write Submission" and type in "I have submitted my Lab Report Via Google docs"
This will allow me to enter a grade that you can see on Blackboard in your grade book for each lab.