Arcadia Public Library

Mitosis requires cells to organize numerous jumbled chromosomes and then separate them with absolute fidelity into two equal groups. How this extraordinary process is accomplished is still poorly understood.. This video reveals the events of mitosis at a level of detail usually seen only in research laboratories. In addition, two Appendices show mitosis in a classical system, the diatom cell, and some experiments on living cells that illustrate why...

Diatoms are an extraordinarily successful group of organisms and their many thousands of species have diversified and specialized so as to occupy every environmental niche. Part of their success derives from their unique protective cell walls, beautifully elaborate structures made of pure silica. However, living inside walls made of this rigid, refractory material creates many problems. Just how diatoms circumvent these problems provides the major...

The Oedogoniales are remarkable filamentous green algae. Their method of cell elongation is unique, utilizing a donut-shaped ring of soft wall material which is stretched to form the new daughter cell. While Oedogonium is a simple filament, the related Bulbochaete and Oedocladium are branched and Bulbochaete differentiates long hair cells. The zoospore is large and multiflagellated. Sexual reproduction is oogamous and either “macrandrous” or “nannandrous.”...

Three dimensional animations, supported by aurthoritative narrations, explore the leaf surface and explain the functioning of the guard cells. The viewer is then taken inside the leaf to see the photosynthesis and conducting cells. Witness the dynamic events of guard cell movements, gas exchange and the transport of water and sugars. Animations also illustrate the forms of leaves and how they are modified for dry and aquatic habitats..

Combining images of living plant stages with computer simulations allows you to easily bridge the gap between the familiar plant and the micro-environment contained within it. Three dimensional animations take you inside the flower to witness dynamic events such as pollination, gametophyte formation, fertilization, embryo formation and fruit formation are seen as spectacular computer simulations..

The Volvocales and Chlorococcales share a common ancestry from a cell type exemplified by Chlamydomonas. Using live cells, this video shows how simple evolutionary trends working on Chlamydomonad ancestors have generated diversity and complexity.. In Volvocalean evolution, unicellular ancestors became multicellular (e.g., Volvox) by daughter cells adhering after division. Concurrently, they evolved various advanced characters (e.g., differentiation...

Reproduction in the red algae is unique. No flagellated stages are ever formed, and it is generally assumed that the various reproductive spores are inert. This video demonstrates that spores in many species are actively motile, either by gliding or amoeboid activity. This limited power of movement may turn out to be of considerable significance in survival strategies (e.g. dispersion, optimization of a germination site).. Sexual reproduction is also...

Explains biological concepts and explores related fields as well as the history of biological science. Discusses critical issues such as embryogenesis and commercial applications of research in biology and addresses ethical issues. Provides information on careers in biology. Contains sidebars, bibliographies, timelines, charts, a glossary, and individual and cumulative indexes.

Millions have sent their DNA to be analyzed by private companies, which are revealing customers' ancestry and family connections, and reporting health risks. But what are the pitfalls and unintended consequences of sharing genetic data?