BIOL108 Chapter Notes - Chapter 32: Neoproterozoic, Homeobox, Cambrian Explosion

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Cynthia Friedman

Document Summary

Animals have a variety of proteins external to the cell membrane that provide structural support to animal cells and connect them to one another. In most animal species, the flagellated sperm fertilizes the egg, and leads to the production of a zygote. This zygote then undergoes cleavage where in it divides without cell growth in between the divisions. Then it forms a blastula, which is a hollow ball multicellular stage. Following the blastula stage is the stage of gastrulation that produces the layers of embryonic tissues that result in the gastrula being formed. These larvae undergo metamorphosis which is a developmental transformation that turns the animal into a juvenile that resembles the adult. All animals have developmental genes encoding transcription factors that regulate the expression of other genes, and many of these regulatory genes contain sets of dna sequences called homeoboxes. Most animals share a unique homeobox containing family of genes known as hox genes.