Ap Bio Lab Fruit Flies
AP Lab Seven Genetics of Organisms
Dan Torres
AP Biology
Block 1
January 24, 2011
Introduction & Background
Fruit flies have made a huge contribution towards knowledge about genetics, but for most people, they are just annoying insects that are attracted to their fruit. Their scientific name is Drosophila melanogaster, and to scientists, they have been a key to understand many principles of heredity including sex linked inheritance, epistasis, multiple alleles, and gene mapping. Fruit flies were the first organisms to be used for genetic analysis in 1910 by Thomas Hunt Morgan, and ever since, they have been used for genetic experiments (Ashburner). There is a huge advantage to using fruit flies instead of another organism. Fruit flies have simple food requirements, they occupy little space (they are contained in vials), they complete their life in about 8-14 days (depending on the temperature), they produce many offspring, and they can be “put to sleep” to examine them (Life). Although there are many factors that determine the life span of the fruit flies, the biggest one is the temperature of the environment they are in. When they are in room temperature, the life cycle lasts for about 10-12 days. It starts by the male depositing his sperm into the female. If fertilization occurs, the female lays about 500 eggs on top of either fruit or any decomposing organic matter. This is the first stage of fruit flies--the egg. The egg is oval and has two filaments at one end, and after about one day, they hatch into larva. The larva is divided into three different stages: the 1st instar, the 2nd instar, and the 3rd instar. The total amount of time that it is in the larva stage is between 3-5 days. During the first instar, the larva eats continuously, tunneling through the medium. It sheds its skin twice, each time, it increases in size. After it molts, it enters the second instar (after about a day). During the second instar, it eats all it can, like a
Dan Torres
AP Biology
Block 1
January 24, 2011
Introduction & Background
Fruit flies have made a huge contribution towards knowledge about genetics, but for most people, they are just annoying insects that are attracted to their fruit. Their scientific name is Drosophila melanogaster, and to scientists, they have been a key to understand many principles of heredity including sex linked inheritance, epistasis, multiple alleles, and gene mapping. Fruit flies were the first organisms to be used for genetic analysis in 1910 by Thomas Hunt Morgan, and ever since, they have been used for genetic experiments (Ashburner). There is a huge advantage to using fruit flies instead of another organism. Fruit flies have simple food requirements, they occupy little space (they are contained in vials), they complete their life in about 8-14 days (depending on the temperature), they produce many offspring, and they can be “put to sleep” to examine them (Life). Although there are many factors that determine the life span of the fruit flies, the biggest one is the temperature of the environment they are in. When they are in room temperature, the life cycle lasts for about 10-12 days. It starts by the male depositing his sperm into the female. If fertilization occurs, the female lays about 500 eggs on top of either fruit or any decomposing organic matter. This is the first stage of fruit flies--the egg. The egg is oval and has two filaments at one end, and after about one day, they hatch into larva. The larva is divided into three different stages: the 1st instar, the 2nd instar, and the 3rd instar. The total amount of time that it is in the larva stage is between 3-5 days. During the first instar, the larva eats continuously, tunneling through the medium. It sheds its skin twice, each time, it increases in size. After it molts, it enters the second instar (after about a day). During the second instar, it eats all it can, like a
Cited: http://faculty.southwest.tn.edu/jiwilliams/probab2.gif