•The frog embryos have been developing for 1 week now at 3 different pHs.
• Fill in the data in for your groups assigned pH in the table below
• Share your data with the class by writing your data on the board.
• Obtain the data from other groups for their assigned pH to complete the table below.
• Determine the percent of embryos that developed into tadpoles for each pH using the following equation:
(# of tadpoles / # of tadpoles + eggs) X 100.
• Use the Percent developed data in the table above to answer questions in Part A of the Lab Report.
• Use the graph paper provided in the pdf of the Lab Report to graph the data in the table above. Place the pH on the x-axis and the % developed on the y-axis. Upload this graph in the proper place in the lab report.
The shell
•We will start by examining the shell.
• Place a beaker of water on a hot plate.
• Once the water is boiling gently add an egg to the boiling water.
• Answer questions about what you observe once the egg is placed in the boiling water.
• When you are done turn the hot plate off and wait for it to cool before removing and disposing of the egg.
• Take another egg.
• Before cracking it open observe the egg and answer questions in Part B of the Lab Report.
• Obtain a finger bowl. Crack the egg into the finger bowl.
• Place the shell on a paper towel.
• We will examine the shell in more detail now. We will focus on the rest of the egg shortly so move it somewhere safe.
• Look at the shell under a dissecting microscope or with a hand lens. You should be able to see the two layered shell membrane. It is easiest to see if you look at the blunt end of the egg where the inner and outer shell membranes have separated from each other.
• Determine the mass of your shell by using one of the balances in the Lab.
Answer questions about the mass of the egg in the Lab Report.
The yolk and albumen
• We will now turn our attention to the rest of the egg.
• Observed the cracked egg in the finger bowl.
• Make observations and answer questions in the lab report.
• Use the figure here and in Part B of the Lab Report to identify the parts of the egg.
• Look at slides and models of cleavage and gastrulation provided in the lab.
• Diagram and label a cleavage stage and as gastrulation stage embryo in the spaces provided in the lab report
• Answer questions in Part C of the Lab Report.
• Look at whole mounts, serial sections and models of a 24 hour chick embryo provided in the lab.
• Answer questions in Part D of the Lab Report.
• Use the figure here and in Part D of the Lab Report to identify the parts of the 24 hour chick embryo.
• Obtain a 33-hour chick whole mount and answer the questions in Part E of the Lab Report.
• Observe the 48 hour chick embryo in this video and determine the number heart beats did you count in 30 seconds and calculate the number of beats per minute.
Click here to watch 48- Hour chick embryo video
• Use the Table below or in the lab report to calculate the average beats per minute (bpm) for each substance applied to the chick embryo and to answer the remaining questions in Part F of the Lab Report.
• Answer the remaining questions in Part F of the Lab Report,
• Answer questions in Part G of the Lab Report.
• Answer questions in Part H of the Lab Report.
• Answer questions in Part I of the Lab Report.