Topic 3 Genetics

1. Topic 3 Genetics • Answers: • 56) Mutations are often referred to as the raw materials of evolution because they allow for variation among species thereby causing them to change over time. • Any combination of the letters ATCG would be acceptable. Here is an example: AAT GGC TAC • Here you could show any of the following three types of mutations: a point mutation, deletion or insertion. Here is an example of a deletion: • AAG GCT AC

2. Answer: Choice 3

3. Answers: 51: One environmental factor that could cause a base sequence in DNA to be changed to a different base sequence would be exposure to radiation (UV rays). 52. The protein’s shape and function would change.

4. Answers: 60: Estrogen or Progesterone 61: Some cells in a female’s body have receptor sites that respond to the reproductive hormones while other cells do not have these receptor sites. 64. Asexual reproduction results in offspring that are genetically identical to the previous generation because the parent cell splits into two daughter cells each with the same number of chromosomes. In sexual reproduction there are two parents in asexual reproduction there is only one parent.

5. Topics 6 & 7Ecology & Environmental Impact • Answers: • 63. Guars produced by normal means have genetic information from both of their parents while clones are genetically identical to their donor parent. • One biological benefit of preserving endangered species would be that it maintains a balanced ecosystem and does not disrupt food webs. • Guars can also be saved by setting up wildlife reserves.

6. Answers: Removing dead corn stalks keeps them from decomposing and from returning vital nutrients back to the ground which is needed for new crops to grow sufficiently.

7. Answers: Biodiversity refers to the variety of species that exist on earth. If biodiversity continues to be lost instabilities within food webs could cause problems for humans who are considered to be top level predators. Wildlife reserves or recycling.

9. Answer question 65 • Both the phytoplankton and the freshwater clam populations will decrease in number. • Oxygen concentrations have decreased in response to the introduction of the zebra mussels into this ecosystem. This will negatively effect both the freshwater clams and other consumers who rely on the oxygen for cellular respiration. • The rate of decay would increase and more materials would then need to be recycled. • The zebra mussel population would increase in numbers at first while there was still an abundance of phytoplankton. Eventually the abundance of phytoplankton will run out and the zebra mussels will decline in number.

10. Global warming is an increase in the greenhouse effect that is caused by human influence. It quite literally refers to the warming of the Earth’s atmosphere. The burning of fossil fuels causes high levels of CO2 to be emitted into the atmosphere amplifying the greenhouse effect. Water levels will continue to rise as polar ice caps melt.