• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

AP Biology Lab Seven: Genetics of Organisms.Hypothesis In the sex linked cross of Drosophila Melanogaster, a phenotypic ratio of 1:1 will be obtained.

Extracts from this document...

Introduction

Transfer-Encoding: chunked AP Biology Lab 7 :Genetics of Organisms Introduction Drosophila Melanogaster, the fruit fly, is a great organism for genetic use because it has simple food requirements, occupies little space, is hardy, completes its life cycle in 12 days, makes a large number of offspring, can be knocked out easily, and it has many types of hereditary variations that can be seen with low power microscopes. Drosophila has a small number of chromosomes, four pairs. They are easily located in the large salivary glands. The Drosophila can be obtained from many places. Research of Drosophilae has led to a lot of knowledge about many of its genes. Many factors combine to affect the length of the Drosophila life cycle. Temperature affects the life cycle the most. At room temperature the average life cycle of the Drosophila is about 12 days. Eggs of the Drosophila are small, oval shaped, and have two filaments at one end. They are usually laid on the surface of the culture medium, and with practice, can be seen with the naked eye. After one day the eggs hatch into the larva. The larval stage of the Drosophila eats all the time. Larvae tunnel into the culture medium when they eat. ...read more.

Middle

Describe the observed mutations? In the F1 generation the males had white eyes and the females had red eyes. In the F2 generation the males and females could have had either red or white eyes. 2. Write a hypothesis which describes the mode of inheritance of the trait you studied. This is your null hypothesis ( as described in the Statistical Analysis Section). For a sex linked cross there will always be a one to one ratio of the phenotypes. In the F1 generation there will be a one to one ratio of red eyed females to the number of white eyed males. In the F2 generation there will be a one to one ratio of red eyed females to white eyed females. There will also be a one to one ratio of red eyed males to white eyed males. 3. Refer to a textbook and review Punnett squares. In the space below construct two Punnett squares to predict the expected results of both the parental and F1 crosses from your null hypothesis. Parental cross Y Xr Xr YXr Xr Xr Xr YXr Xr Xr F1 cross Y Xr Y XR XR YXR XR Xr YXR XRXR XR YXR XR Xr YXr XR Xr Xr YXr XrXr YXr X RXr Xr YXr XrXr YXr XRXr 4. ...read more.

Conclusion

There will be 333 long winged flies. 666 intermediate winged flies. There will be 33 short wing flies. c. Complete the table Table 7.8 Observed Phenotypes Expected (e) (o-e) (o-e)2 (o-e)2/ e LL 333 -103 10609 31.86 Ll 666 -156 24336 36.54 ll 333 -73 5329 16.00 84.4 1. How many degrees of freedom are there? There are 2 degrees of freedom. 2. Chi-Square= 84.4 3. Referring to the critical values chart, what is the probability value for these data? Less than .001. 4. According to the probability value can you except or reject the null hypothesis? I can reject the null hypothesis because the Chi-square answer is greater than the critical value from the table. Error Analysis Results from this lab could have been affected by many things. The constant knocking out of flies could have caused some of the larvae to not hatch therefore affecting our numbers. Also, incorrectly identifying the characteristics of the flies could have also greatly affected the results received. Improper calculation of numbers could have also caused inaccurate results. Finally, some flies could have gotten stuck in the medium and could have been identified. Conclusion From the results of the experiment I can conclude that I received results that were close to a 1:1 ratio. The Chi- Square worked from my data was accepted at a possibility greater than .05. The null hypothesis in this case can be accepted. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Genetics, Evolution & Biodiversity section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Genetics, Evolution & Biodiversity essays

  1. Marked by a teacher

    An Investigation into the Mitotic Nuclear Division of Allium Sativum Root Tip Cells, and ...

    5 star(s)

    This concept is somewhat reinforced by the background research ratio, which demonstrates Telophase to be the second longest phase, closely following prophase. This was the trend also in the observed experimental results; demonstrating the degree to which the background cellular ratio is corroborated and reinforced by the gained results.

  2. Marked by a teacher

    The daphnia lab report

    3 star(s)

    Guarana- a small red fruit's black seeds are known as Brazilian coco beans that act like a stimulant. It is recommended that people with heart diseases shouldn't use this stimulant (Alternative Medicine). This will stimulate the daphnia's CNS and its heart rate will increase.

  1. Blackfly larvae

    At this point, I can then pour the contents of the bucket into my tray, and then count how many Simuliidae larvae I have caught for that particular sample area. Once I have counted them, I will pour the contents of the tray back into the river, and then I

  2. The Biology of Autistic Spectrum Disorder and the Social Implications

    AUTOSOMAL DOMINANT INHERITANCE Autosomal means there is no discrimination between whether or not males or females are affected as both have a 50/50 chance of inheriting a faulty gene. In dominant inheritance, the chance of passing on a disorder is 50 per cent for each pregnancy and if the gene is inherited, it will result in an affected individual.

  1. Investigate how the height to width ratio of Limpets varies with distance from sea

    The mucus contains high levels of Nitrogen which stimulate the growth of more algae. The shape of their shell often grows to precisely match the contours of the rock surrounding the scar, consequently allowing the Limpet to form a better seal to the rock(3)

  2. Evaluating generations of fruit flies for inherited characteristics.

    However the large winged flies are around 2.4 times larger than the number of vestigial winged flies and it could be considered that it is only about two times the amount of vestigial winged flies. Task 2 ? Dihybrid Cross P1 Generation: 1.

  1. How Does The Oxygenation Level Of The Water Affect The Number Of Stonefly Larvae?

    Aerobic respiration may be represented by the general equation: C6H12O6 + 6O2 6CO2 + 6H2O. About 3000 kJ mol-1 of energy is released. Burning glucose in air would release this amount of energy in one go. However, it is not as simple as this in aerobic respiration.

  2. Hypothesis: There will be a difference between the average hand size of males ...

    Calculate the average of the length of the seven grade 10 male students' hands. 6. Repeat steps one through five for the female portion of this experiment. Results: Results: First chosen grade 10 female student's hand measures 17.50 cm � 0.05 in length, 15.80 cm � 0.05 in width (Table 1).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work