biology notes class

CULTURE OF DROSOPHILAAND ITS LIFE CYCLE An Introduction to Drosophila melanogaster Drosophila melanogaster is a small, common fly found near unripe and rotted fruit. It has been in use for over a century to study genetics and behavior. Thomas Hunt Morgan was the preeminent biologist studying Drosophila early in the 1900’s. He was the first to discover sex-linkage and genetic recombination, which placed the small fly in the forefront of genetic research. Due to its small size, ease of culture and short generation time, geneticists have been using Drosophila ever since. Fruit flies are easily obtained from the wild and many biological science companies carry a variety of different mutations. In addition these companies sell any equipment needed to culture the flies. Costs are relatively low and most equipment can be used year after year. There are a variety of laboratory exercises one could purchase, although the necessit

THE EVOLUTION OF THE HEART • Heartis a muscular organ . As per evolutionary point of view the chamber of heart are, 1.SINGLE CHAMBER HEART • It is found in primitive chordates like amphioxus. • It is not a true heart. 2. TWO CHAMBER HEART • It is found in pises. • It is true heart chamber. • 2heart chamber                  a. Atrium- receving chmber                  b. Ventricle-pumping chamber • 2 chanber animals also contains gills for respiration. • Heart of fish receive only deoxygenated blood. • This type heart is calledbranchialheart or venus heart. • It is a single circulation path or haert. Sinus                                 atrium                    ventricle venosus                                                                                                                                                                              conus arteriosus  deoxyganated blood                            oxygenated