Skill Development/Guided Practice Mutation is a change made to the DNA of an organism. Mutations in the DNA may result in an organism making different proteins or stopping a protein from being made. New traits that are expressed by these different proteins can have harmful, beneficial 1, or neutral effects on the structure and function of an organism. Mutation Effects Survival and Environmental Factors Colorblindness Hemophilia Disease: Sickle-cell Disease/Trait Trait:
Skill Development/Guided Practice (continued) 1. DNA contains all of the genes that an organism uses to create itself and function. 2. Most of this work is done through the creation of proteins. 3. Proteins serve many different functions in the body. 4. The change of a single molecule in the DNA can significantly change an organism. 5. Changes in DNA can change the structure of a protein, prevent a protein from being made, or even stop entire parts of the organism from forming. 6. Colorblindness is caused by mutations in the DNA instructions that build the light-sensing cells in the eye. 7. There are two kinds of cells that sense light, rods and cones. 8. Cones sense different colors of light while rods sense the presence of light but not its color. 9. Colorblindness occurs when a particular kind of cone cell is not created. 10. When one of the three kinds of cones are not built in the eye, a person has difficulty sensing certain colors. 11. The most common kind of color blindness, red-green colorblindness, makes it difficult to tell the difference between the colors red and green. 12. This decreased color sensing ability does not significantly affect the life of most people. 13. Even the true color blindness (only seeing in black and white) is considered only a mild disability. 14. For most modern people, the most inconvenient result of colorblindness is wearing navy blue socks with black pants. 15. There is some evidence that in the past, when many people hunted, colorblindness gave a slight advantage in seeing through camouflage, but the benefit was never enough to significantly influence survival. 16. Hemophilia is caused by mutations in the DNA instructions for making special proteins called healing factors. 17. These proteins help platelets in the blood form clots to stop bleeding. 18. They fill in smaller holes in a clot and help reinforce scabs once they have been formed. 19. People with this mutation do not create enough of these proteins. 20. Without enough of these healing factors, people can have uncontrollable bleeding. 21. Even fairly mild cuts can bleed for days and a minor car crash can cause fatal internal bleeding. 22. Until the 1960s, when effective treatments were developed, someone with severe hemophilia was only expected to survive to be 11 years old. 23. Today, it is very treatable with people living nearly normal lives. 24. So long as they are willing to forego risky activities, like full-contact football and skydiving, their lives are mostly unaffected.
Skill Development/Guided Practice (continued) 25. The condition known as Sickle-cell Disease is a good example of the environment making a mutation beneficial. 26. It is a genetic disorder that is caused by the change of a single molecule on someone s DNA. 27. This changes the hemoglobin protein in the red blood cells. 28. In certain conditions, the changed hemoglobin proteins link together. 29. This distorts the red blood cells from their normal flattened disc shape into a long sickle 4 shape. 30. These cells are less elastic 5 and have difficulty passing through narrow blood vessels in the body. 31. This can lead to a variety of problems including blockages, pain, and high blood pressure. 32. The blood cells also die more quickly. 33. Normal blood cells last between 3 and 4 months. 34. The deformed sickle cells only last for 10 to 20 days. 35. This causes many other problems in the body, like anemia 6 and problems with the spleen and kidneys. 36. Sickle-cell disease shortens the life of someone with it by many years. 37. Normally, harmful mutations are rare, but this one is not. 38. In some areas of the world, 40% of people have the mutation. 39. This is very strange. 40. The reason has to do with the environment. 41. Areas where the trait is most common are in tropical climates. 42. Tropical areas are where a disease called malaria is common. 43. Malaria is a very dangerous disease and is often deadly. 44. It is caused by a parasite called plasmodium that infects the blood. 45. Malaria is actually the reason that the Sickle-cell mutation is so common. 46. Sickle-cell Disease is a recessive trait. 47. That means that it has to be inherited from both the mother and the father to have the disease. 48. Only receiving the mutation from one parent means that the person has Sickle-cell Trait. 49. Someone with Sickle-cell Trait produces most of their hemoglobin normally. 50. A person with Sickle-cell Trait can lead a normal life. 51. The single copy of the mutation also provides resistance to the parasite that causes malaria. 52. This helps explain why a potentially deadly mutation is so common in some areas. 53. The environment provides a survival benefit for the population with only one copy of the mutation that outweighs those with two copies living shorter lives. Vocabulary 4 crescent 5 squishy and pliable 6 a condition of having too few red blood cells or too little hemoglobin
Independent Practice Name Mutation is a change made to the DNA of an organism. Mutations in the DNA may result in an organism making different proteins or stopping a protein from being made. New traits that are expressed by these different proteins can have harmful, beneficial 1, or neutral effects on the structure and function of an organism. English Peppered Moths Peppered moths are a common insect living in England and other parts of Europe. Most of the moths are lightly colored and match the light-colored bark of the trees they live in. While the most peppered moths are light, some have a mutation that causes them to have dark bodies. In the past, these darker moths were very rare. They were more visible to predators and were eaten. But around 150 years ago, the darker moths became more common. During that time, England was experiencing what is known as the Industrial Revolution. Factories were being built, and they ran by burning coal for fuel. The result was a dark smoke that covered the countryside. Trees that were lightly colored were now covered in a layer of soot. The mutation for dark moths was no longer a negative survival trait. They were instead better camouflaged on the sootdarkened trees. The lighter colored moths were more visible to predators and were eaten more often. As a result, fewer lighter moths reproduced and the dark moths became far more common. Mutation Effects Survival and Environmental Factors Dark coloration on the English Peppered Moth In your own words, describe whether the mutation was harmful, beneficial, or neutral. Justify your answer.
Access Concepts and Experimentation Chose one kind of mutation from the list below. Use the internet to research the subject and create a research paper describing a specific set of mutations and how they have affected the organism and its survival. Include information from at least 3 different sources and include at least one image that illustrates the mutation. Research topics domestication of one of the following organisms: dogs, wheat, corn/maize, almonds Galapagos finches: changes in beak specialization