BIOL 20235: Biological Systems

Explore the distinct characteristics of muscle tissues and their functions. Understand the differences between skeletal, cardiac, and smooth muscles. Get insights into the anatomy of striations, cell shapes, and nuclei.

Discover the complex world of sea urchin reproduction, focusing on the essential role the cortical reaction plays in egg fertilization. Uncover common myths surrounding this process and learn what actually happens at the cellular level. Gain insight into how the formation of a fertilization envelope is crucial for successful fertilization.

Explore the influential Three-Domain System of classification, introduced by Carl Woese in 1978. Discover how it categorizes life into Bacteria, Archaea, and Eukarya based on distinctive cellular structures. Learn about the characteristics of each domain, from prokaryotic Bacteria and Archaea to the rich diversity within Eukarya, encompassing Protists, Fungi, Plants, Animals, and the unique world of viruses.

Explore the application of parsimony in constructing phylogenetic trees, emphasizing simplicity in scientific explanations and its relation to evolutionary changes. Learn about various options for tree construction and the core concept of choosing the most parsimonious representation

Discover the mechanics of voltage-gated Na+ channels and their role in neuron activity. This video breaks down key neuronal terms like resting potential and threshold to explain precisely when these channels open. You'll come away understanding that voltage-gated Na+ channels open at the threshold state initiating an action potential.

Explore the complexities of epithelium tissue and its diverse types. Understand their distinct functions, ranging from protection to secretion and absorption, and learn about their various locations in the body. Highlighting the significance of epithelial cells in vital physiological processes.