Answers to Question Set 1

Here are the answers to question set 1.
1. Most doctors would prescribe antibiotics to be taken for a couple of days. Patients would be required to take in the medicine completely according to the prescribed number of days. Doctors say that the medicine will be ineffective the second time you use it for the same illness if you don't complete the prescribed number of days, why is this so? Explain in evolutionary terms.
Answer:
Before I answer this question, take note of the kind of medicine that is used in this problem - Antibiotics. This would mean that the disease in question here is caused by bacteria which has several species that may thrive within the human intestine or the part of the body which is infected if you unfortunately ingest or contract it.
Doctors would prescribe the intake of antibiotics for about 5-7 days. This is done so that all the bacteria inside the body will be eliminated or that there would be no chance for bacteria to survive within the infected body. When a patient does not adhere to or follow the prescription period for which he is to take the antibiotics, he is increasing the ability of the bacteria to ADAPT to the antibiotics ability to kill them. At first use or within a few days since the patient started taking the medicine, the patient may feel "well." But this feeling of wellness does not guarantee that all bacteria in the affected part have been totally killed. If the patient does not follow the prescription period, the remaining bacteria will have increased FITNESS and thus, will be able to REPRODUCE offsprings that are NOT SUSCEPTIBLE anymore to that particular antibiotic. Hence, we have a change in the bacteria's trait or characteristic. Thus, doctors would require the patient another drug which may be stronger than the previous antibiotic taken by the patient.
2. How would you explain the different finch species found in the Galapagos Islands?
Answer:
Differences in the finch species found in the Galapagos Islands were brought about by (1) the differences in the environmental conditions found within each island and (2) the type of food supply found within each island.
3. Which pattern of macroevolution would explain the disappearance of dinosaurs at the end of the Mesozoic era?
Answer:
Scientists agreed, based on evidence, that the disappearance of the dinosaurs at the end of the Mesozoic era was caused by MASS EXTINCTION. Only this pattern of macroevolution could have brought about such drastic changes in terms of the species that were found on Earth during those time. At present, the main cause of this mass extinction is said to be the collision of a big asteriod and our planet Earth.
4. Natural selection affects polygenic traits in three different ways. In which way will natural selection produce two different phenotypes (observable/outward characteristics)? Why?
Answer:
Focus on the phrase "two different phenotypes." Natural selection affects polygenic traits in three different ways: directional selection, stabilizing selection, and disruptive selection. Among the three ways, it is only in DISRUPTIVE SELECTION that nature favors the existence of two extreme traits (remember the small, medium, large analogy?). Thus, the production of two phenotypes from the same species can only happen if their is disruptive selection.
5. Why do scientists study populations instead of individual species when talking about evolution?
Answer:
Scientists study populations when talking of evolution because it is in a population that changes are very noticeable and that it is a population that passes the traits to their next generation. Although each individual in a population could experience changes or evolution through mutation or gene shuffling, these changes will only be passed on to his descendants and would only have a minimal effect on the gene pool of a population.
6. What does "survival of the fittest" mean? Does it always refer to physical traits? Explain.
Answer:
Survival of the fittest means that only an organism that is well-adapted and fit to his environment will survive. It does not always refer to that which is physical but also to the other aspects which make-up an individual organism. Say for example, in humans we have what is known as "street smart." Left alone in another place or region, a human being who is street smart can survive in that new territory even if he is not that big or strong. What will make him survive is his natural ability to find ways which would satisfy his needs (like food and shelter)in order to survive.
7. Which pattern of macroevolution would best explain the similat appendages found in sharks, dolphins, and penguins? Explain.
Answer:
All the three animals mentioned in the question are capable of swimming in the sea. They find their food in the sea and thus, they are faced with the same environment. This is where CONVERGENT EVOLUTION happens. You have different organisms but one environment that would cause them to develop adaptive body parts in order for them survive.
8. The Law of Superposition states that, "in an undeformed sequence of sedimentary rock, the lower layer is older than the one on top of it." Why does it have to be an undeformed sequence of sedimentary rock?
Answer:
Take note that when we talk of the Law of Superposition, we are talking here of layers of sedimentary rocks. If these sedimentary rocks were deformed, then it would be very difficult to know which layer was formed first and which layer came in next. So, as a consequence, we will not be able to know the age of the rock in question.
9. How can two species that look very different from each other be more closely related than two other species that look similar to each other?
Answer:
Let us dissect the problem first. We are given (1) two species that LOOK very different from each other but are RELATED and (2) two species that LOOK similar to each other but are NOT RELATED. How can the two happen?
We should remember that their are a lot of factors that can affect the development of a particular species such as the environment in which the species are constantly exposed to, the place where the species live, and the food supply available to the species. In the first (1) case, these two species could have been exposed to different environmental conditions thus the need to develop or evolve certain adaptive body parts became important. With the adaptations came the differences in the physical appearance (looks!) of the related species. In the second (2) case, the two unrelated species could have been exposed to the same environmental conditions as in the case of Convergent Evolution. With the same environmental condition, the unrelated species then developed similar body parts that made their physical appearance (looks!) the same.
10. Describe one way that the lack of genetic variation could affect the survival of a species.
Answer:
The lack of genetic variation could lead to the DEATH of a species. If the species does not have any variety, then it could affect the way that the species react to any given changes in its environment. The inability to react to these changes would slowly decrease the species chances of survival and thus, the death of the species.