<p><span style="font-size: 16px;">The process in which an organism develops from a single-celled zygote to a multi-cellular organism is complex and well-regulated. The early stages of embryonic development are also crucial for ensuring the fitness of the organism.<span id="fs-idp40382448" style="box-sizing: border-box; display: block; margin: 0px; text-align: center; color: #555555; font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; line-height: 20px;" data-type="media" data-alt="Part A is a micrograph that shows a sperm whose head is touching the surface of an egg. The egg is much larger than the sperm. Part B is an illustration that shows the surface of the egg, which is coated with a zona pellucida. The sperm penetrates the zona pellucida and releases its DNA into the egg. At this point, changes in proteins just inside the egg’s cell membrane occur, preventing entry of other sperm."><img src="http://cnx.org/resources/019a428cf8427451b5eff4f52037ec5dcd56de29/Figure_43_05_01ab.jpg" alt="Part A is a micrograph that shows a sperm whose head is touching the surface of an egg. The egg is much larger than the sperm. Part B is an illustration that shows the surface of the egg, which is coated with a zona pellucida. The sperm penetrates the zona pellucida and releases its DNA into the egg. At this point, changes in proteins just inside the egg’s cell membrane occur, preventing entry of other sperm." width="445" style="box-sizing: border-box; vertical-align: middle; max-width: 100%;" data-media-type="image/jpg" /></span><span style="font-size: 13px;">(a) Fertilization is the process in which sperm and egg fuse to form a zygote. (b) Acrosomal reactions help the sperm degrade the glycoprotein matrix protecting the egg and allow the sperm to transfer its nucleus. (credit: (b) modification of work by Mariana Ruiz Villareal; scale-bar data from Matt Russell)</span></span></p> <p style="margin: 1em 0px; padding: 0px; outline: 0px; word-wrap: normal; line-height: 16.8px; word-break: normal;"><strong style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px; line-height: 1.4;">Complete the tasks on the list below:</span></strong></p> <ul style="outline: 0px; word-wrap: normal; word-break: normal; line-height: 16.8px;"> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px; line-height: 1.4;">Read the following page in the OpenStax textbook</span></li> <ul style="outline: 0px; word-wrap: normal; word-break: normal;"> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px;"><a href="http://cnx.org/contents/GFy_h8cu@10.53:yBBerJPE@3/Fertilization-and-Early-Embryo">Fertilization and Early Embryonic Development</a> </span></li> <ul style="outline: 0px; word-wrap: normal; word-break: normal;"> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px;">Read the entire page</span></li> <ul style="outline: 0px; word-wrap: normal; word-break: normal; line-height: 16.8px;"> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="font-size: 16px;">Visit the <a href="http://www.ehd.org/virtual-human-embryo/">Virtual Human Embryo</a> site. </span></li> </ul> </ul> </ul> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px;">Use the Glossary at the bottom of the page to help with the vocabulary for this week</span></li> <li style="margin: 0px; outline: 0px; word-wrap: normal; word-break: normal;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px;">Use the Review Questions and Free Response questions to check for understanding</span></li> </ul> <p style="margin: 1em 0px 0px; padding: 0px; outline: 0px; word-wrap: normal; line-height: 16.8px; word-break: normal; text-align: right;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-size: 16px;"><span style="margin: 0px; padding: 0px; outline: 0px; word-wrap: normal; word-break: normal; font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; line-height: 20px;">Download for free at <a class="sExtlink-processed" style="margin: 0px; padding: 0px; outline-width: 0px; word-wrap: normal; color: #3a549a; word-break: normal;" href="http://cnx.org/contents/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.53">http://cnx.org/contents/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.53</a></span></span></p>