How to find conflicting viewpoints in biology
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ACT Science › How to find conflicting viewpoints in biology
Scientist 1
In any population wherein some individuals are susceptible to a given disease, the prevalence of that disease is as much determined by the fraction of the population that is immune as by other environmental factors. If the majority of members in a community are immune, even those who are still susceptible are afforded some degree of protection by herd immunity. The spread of disease is limited by the creation of a large immune population, which benefits the entire community. This is why it is so important to immunize as many people as possible against dangerous contagious diseases, as it protects not only those who have been immunized, but those who have not.
Scientist 2
It is true that immunizing individuals provides some protection against contagious diseases, but the value of "herd immunity" has been overblown. The threshold at which a large enough proportion of the population has been immunized so that contagions cannot spread—the herd immunity threshold—depends on the virulence of the particular disease, as well as the effectiveness of the vaccine and the parameters of contagion. It is much easier to immunize a population against a disease that is only spread through blood-to-blood contact than against one that is airborne; thus, the usefulness of the herd immunity phenomenon is so limited that it is basically negligible. Instead of focusing on immunizing some percentage of the population in the hopes of reaching the herd immunity threshold, we should increase our efforts to limit the spread of various diseases through proper hygiene procedures and limiting contact with high-risk sources.
Scientist 1 would most likely disagree with which of the following?
All diseases have a relatively low herd immunity threshold.
Environmental factors play a significant role in the prevalence of disease.
The effectiveness of herd immunity depends on the proportion of the population that has been immunized.
Non-contagious diseases, such as those caused purely by genetics, would not be preventable through herd immunity.
The herd immunity threshold will always be over half of the individuals in the population
Explanation
Scientist 1 asserts that herd immunity can be an effective tool in controlling the spread of contagious diseases, but does not claim that all diseases have a low herd immunity threshold. Scientist 1 argues for herd immunity as a means of combatting contagious diseases. Non-contagious diseases, such as genetic disorders, will not be affected by herd immunity. Also, specific attributes of a certain disease may increase its virulence, leading to a high herd immunity threshold. Scientist 1 does not argue that all diseases will have low thresholds, and would likely disagree with this statement.
The other answer options are all implied by Scientist 1's argument. He states that proportional immunity is as important "as other environmental factors" in determining overall prevalence, which suggests that environmental factors do play a significant role. He also states that "a majority" of a population would need to be immunized in order to achieve herd immunity; thus, any herd immunity threshold would be over half of the population.
Before modern technologies and experiments allowed scientists to understand different organisms' mechanisms of reproduction, numerous theories existed about how populations came to exist. Two scientists from the 1800s describe their theories. Here are their arguments.
Scientist I
Just like some plants come from seeds and others are capable of vegetative (asexual) reproduction, some animal organisms come from non-sexual reproduction as well. Maggots, for example, appear on rotting carcasses. It is clearly illogical to suggest that the dead animal created or gave birth to the maggots, as it is no longer alive and is therefore incapable of sexual reproduction. The only rational conclusion for the appearance of maggots is a spontaneous generation. This is similar to how, if one were to leave a bowl of broth in the open air for a week, it would turn cloudy from bacteria appearing in the liquid.
Scientist II
Animate objects cannot arise from inanimate objects. Even when plants perform asexual reproduction, daughter plants are still coming from parent plants. There is no other example in nature of a living organism spontaneously coming into being. It is true that we observe maggots on rotting carcasses, but that does not necessarily mean that the maggots came from the rotting carcass. Similarly, bacteria growing in broth do not necessarily come directly from the broth. If a living organism appears, then it must have come from another animate object, even if we did not witness it. It is more likely that these invisible organisms have come in through the air and we simply do not see them until they have had a chance to replicate in these locations.
Fungal spores are placed on a slice of melon. After a certain amount of time, the only fungi that appear on the melon are the same species as the spores. What conclusion would Scientist II draw from this experiment?
The fungi came from the spores, not from spontaneous generation
The experimental species of fungus can only grow on melon
Fungi grow more slowly on melons
The fungus would have appeared on the melon regardless of the initial spores added
Explanation
Scientist II would use this result as further proof that fungi do not come from spontaneous generation, but from the spores themselves. The spores would allow reproduction of only the same species. If spontaneous generation occurred, we may expect to see several species on the melon.
In the 19th century, there were two competing views as to how diseases spread.
Miasma theory:
Miasma (Greek for pollution) is a poisonous vapor that comes from rotting carcasses or other diseased bodies. It carries particles of the decomposing matter in it and spreads illness. This is why the bubonic plague spread so quickly in Europe: the air itself was foul-smelling and polluted with disease which caused everyone in the locale to become sick and die. It also explains why epidemics tend to originate in a certain area and infect everyone within that area -- they are all breathing in this noxious gas and getting the same disease. In hospitals, we need to ensure that the air is fresh smelling and clean so as to avoid all patients breathing in this miasma and all getting sick.
Germ theory:
Disease is spread through small microbial organisms called germs. These germs, which can be bacteria, viruses, or other pathogens, should be able to be isolated from an infected host and then should no longer exist in the host's body when the host becomes healthy. Germs can move from one body to another through direct or indirect contact -- they can move through touching, spreading of fluids (coughing, sneezing, etc.) and potentially air, but not exclusively through the air.
Which of these solutions would a proponent of miasma theory give to someone who is sick?
Move to an area with fresh air, away from where you currently are.
Take antibiotics.
Wash your hands daily and don't touch people.
Stay close to a heating source to keep your temperature consistent.
Explanation
People who support miasma theory believe that disease is transmitted through a foul-smelling vapor. The best way to avoid this disease (or to get better) would be to avoid this vapor.
Antibiotics would be a result of germ theory.
Washing your hands and staying away from people also would be a part of germ theory.
A heating source is not mentioned by either theorist, therefore it is irrelevant.
Vaccinations have become a controversial topic in the United States. Currently the US Food and Drug Administration (FDA) regulates all vaccines. The federal government does not mandate vaccinations for any individual; however, all states require vaccinations for children entering public school. There are several types of vaccines—live attenuated vaccines, inactivated vaccines, subunit vaccines, toxoid vaccines, and conjugate vaccines, just to name a few. All of these vaccines have the shared purpose of exposing the host body to antigens of a specific disease. When the body receives the antigens, the immune system is activated, remembering the antigens. The next time the individual is exposed to the disease, the body will remember the antigen and have a better probability of not getting infected. Two scientists below discuss their belief on vaccines.
Scientist 1
Vaccines have saved many lives. The risks of not being vaccinated far outweigh the risks of adverse vaccine reactions. Reports linking autism to vaccines have been evaluated by the CDC, which states there is no scientific link between autism and vaccines. The second leading cancer killer in women is cervical cancer. The HPV vaccine protects against the two most common strains causing cancer. This is an example of a vaccine that does much more good than bad. Vaccines also reduce the amount of money spent on healthcare, because the preventative cost of a vaccine is much cheaper than the cost of treating an infected person. The only time a vaccine should not be administered is if the chance of the individual coming into contact with the disease is so rare it is not worth the potential of adverse reactions.
Scientist 2
Many vaccines nowadays are extraneous. Vaccines for diseases like whooping cough and scarlet fever were once necessary but now outdated. Modern updates on hygiene, waste management, and water filtration have resulted in significantly decreased chances of infection. In addition, diseases like rotavirus have an infection period of a few days, and the main symptom is dehydration. Modern medicine can easily treat severe dehydration, and the risk of rotavirus infection is very slim; therefore, the results of infection are far milder than the results of an adverse reaction. Vaccines for children can cause extremely dangerous adverse reactions. This includes anaphylactic shock, paralysis, and death. While scientists have not been able to conclusively prove this, many believe that these reactions are related to the age of the host and the lack of a developed immune systemor neural network. Vaccines suppress the immune system, which can lead to autoimmune disorders. In addition, vaccines can congest the lymphatic system with proteins molecules from the vaccines; therefore, I would recommend requirements for vaccination to take place at a later stage in a child’s development.
What biological reactions does Scientist 2 mention as negative results of vaccination
all of the choices listed
congest the lymphatic system
autoimmune diseases
anaphylatic shock
paralysis
Explanation
Scientist 2 states that "vaccines for children can cause extremely dangerous adverse reactions. This includes anaphylactic shock, paralysis, and death." Scientist 2 also mentions that "vaccines can congest the lymphatic system with protein molecules from the vaccines." Lastly he also states that "vaccines suppress the immune system, which can lead to autoimmune disorders."
Three doctors are discussing the most optimal way to approach cancer treatment. While they all acknowledge that cancer is uncontrolled cell proliferation, they have different opinions on whether chemotherapy is the best treatment method. Chemotherapy is the treatment of cancer with cytotoxic antienoplastic drugs. These drugs are used to kill fast-growing cancerous cells. All three doctors agree that chemotherapy has many associated side effects.
Doctor 1
While the drugs used for chemotherapy can be very strong, they need to be. Cancer, by its very definition, is made up of cells growing at a faster than normal rate. This means the treatment needs to be aggressive. The slower the effects of treatment, the more time the cancer has to spread; therefore, while the chemotherapy can also kill some healthy noncancerous cells in the process, it is still the best option.
Doctor 2
Chemotherapy does much more harm than good. Chemotherapy might temporarily destroy the cancer, but it does not cure the cancer. In addition, killing the cancerous cells means poisoning the body with chemicals and toxins. Instead, we should be addressing the reasons cancer exists in the first place, treating it at that step. Cancer is due to toxins in the body, industrial pollutions, and drugs. Avoiding sugar, exercising, and maintaining a healthy lifestyle—free of toxins, processed food, and other containments—is the best approach.
Doctor 3
Chemotherapy is effective in the sense that it kills the cancer cells. The downfall is that chemotherapy also kills the healthy cells in the process; therefore, we should be looking at way to decrease the amount of chemotherapy needed, so that we are only introducing the minimum amount of toxins into the body. Insulin Potentiating Therapy is a type of chemotherapy in which lower doses of chemotherapy are used because they are combined with insulin. Cancer cells have more insulin receptors than non-cancerous cells; therefore, cancer cells will have a biased absorption of such insulin-based chemotherapy when compared with noncancerous cells. In other words, piggybacking chemotherapy onto insulin allows cancer cells to absorb more of the chemotherapy, meaning less chemotherapy is needed and fewer noncancerous cells absorb the chemotherapy.
Which doctor could you infer would recommend a preventative approach to cancer as opposed to chemotherapy?
Doctor 2
None of the doctors
Doctor 3
Doctor 1
All three doctors
Explanation
Doctor 2 discusses why he believes people get cancer in the first place. He attributes them to toxins and chemicals, and urges people to focus on their health and nutrition to prevent these toxins from entering the body.
Three doctors are discussing the most optimal way to approach cancer treatment. While they all acknowledge that cancer is uncontrolled cell proliferation, they have different opinions on whether chemotherapy is the best treatment method. Chemotherapy is the treatment of cancer with cytotoxic antienoplastic drugs. These drugs are used to kill fast-growing cancerous cells. All three doctors agree that chemotherapy has many associated side effects.
Doctor 1
While the drugs used for chemotherapy can be very strong, they need to be. Cancer, by its very definition, is made up of cells growing at a faster than normal rate. This means the treatment needs to be aggressive. The slower the effects of treatment, the more time the cancer has to spread; therefore, while the chemotherapy can also kill some healthy noncancerous cells in the process, it is still the best option.
Doctor 2
Chemotherapy does much more harm than good. Chemotherapy might temporarily destroy the cancer, but it does not cure the cancer. In addition, killing the cancerous cells means poisoning the body with chemicals and toxins. Instead, we should be addressing the reasons cancer exists in the first place, treating it at that step. Cancer is due to toxins in the body, industrial pollutions, and drugs. Avoiding sugar, exercising, and maintaining a healthy lifestyle—free of toxins, processed food, and other containments—is the best approach.
Doctor 3
Chemotherapy is effective in the sense that it kills the cancer cells. The downfall is that chemotherapy also kills the healthy cells in the process; therefore, we should be looking at way to decrease the amount of chemotherapy needed, so that we are only introducing the minimum amount of toxins into the body. Insulin Potentiating Therapy is a type of chemotherapy in which lower doses of chemotherapy are used because they are combined with insulin. Cancer cells have more insulin receptors than non-cancerous cells; therefore, cancer cells will have a biased absorption of such insulin-based chemotherapy when compared with noncancerous cells. In other words, piggybacking chemotherapy onto insulin allows cancer cells to absorb more of the chemotherapy, meaning less chemotherapy is needed and fewer noncancerous cells absorb the chemotherapy.
Which doctor could you infer would recommend a preventative approach to cancer as opposed to chemotherapy?
Doctor 2
None of the doctors
Doctor 3
Doctor 1
All three doctors
Explanation
Doctor 2 discusses why he believes people get cancer in the first place. He attributes them to toxins and chemicals, and urges people to focus on their health and nutrition to prevent these toxins from entering the body.
In the 19th century, there were two competing views as to how diseases spread.
Miasma theory:
Miasma (Greek for pollution) is a poisonous vapor that comes from rotting carcasses or other diseased bodies. It carries particles of the decomposing matter in it and spreads illness. This is why the bubonic plague spread so quickly in Europe: the air itself was foul-smelling and polluted with disease which caused everyone in the locale to become sick and die. It also explains why epidemics tend to originate in a certain area and infect everyone within that area -- they are all breathing in this noxious gas and getting the same disease. In hospitals, we need to ensure that the air is fresh smelling and clean so as to avoid all patients breathing in this miasma and all getting sick.
Germ theory:
Disease is spread through small microbial organisms called germs. These germs, which can be bacteria, viruses, or other pathogens, should be able to be isolated from an infected host and then should no longer exist in the host's body when the host becomes healthy. Germs can move from one body to another through direct or indirect contact -- they can move through touching, spreading of fluids (coughing, sneezing, etc.) and potentially air, but not exclusively through the air.
In 1876, Robert Koch proved that anthrax was caused by a bacterium. Which of these the two theories does this proof best support?
Germ theory
Miasma theory
Neither theory
Both theories
Explanation
This proof supports germ theory as germ theory states that diseases come from viruses, bacterium, and other pathogens instead of a "vapor" that causes sickness.
In the 19th century, there were two competing views as to how diseases spread.
Miasma theory:
Miasma (Greek for pollution) is a poisonous vapor that comes from rotting carcasses or other diseased bodies. It carries particles of the decomposing matter in it and spreads illness. This is why the bubonic plague spread so quickly in Europe: the air itself was foul-smelling and polluted with disease which caused everyone in the locale to become sick and die. It also explains why epidemics tend to originate in a certain area and infect everyone within that area -- they are all breathing in this noxious gas and getting the same disease. In hospitals, we need to ensure that the air is fresh smelling and clean so as to avoid all patients breathing in this miasma and all getting sick.
Germ theory:
Disease is spread through small microbial organisms called germs. These germs, which can be bacteria, viruses, or other pathogens, should be able to be isolated from an infected host and then should no longer exist in the host's body when the host becomes healthy. Germs can move from one body to another through direct or indirect contact -- they can move through touching, spreading of fluids (coughing, sneezing, etc.) and potentially air, but not exclusively through the air.
In 1876, Robert Koch proved that anthrax was caused by a bacterium. Which of these the two theories does this proof best support?
Germ theory
Miasma theory
Neither theory
Both theories
Explanation
This proof supports germ theory as germ theory states that diseases come from viruses, bacterium, and other pathogens instead of a "vapor" that causes sickness.
In the 19th century, there were two competing views as to how diseases spread.
Miasma theory:
Miasma (Greek for pollution) is a poisonous vapor that comes from rotting carcasses or other diseased bodies. It carries particles of the decomposing matter in it and spreads illness. This is why the bubonic plague spread so quickly in Europe: the air itself was foul-smelling and polluted with disease which caused everyone in the locale to become sick and die. It also explains why epidemics tend to originate in a certain area and infect everyone within that area -- they are all breathing in this noxious gas and getting the same disease. In hospitals, we need to ensure that the air is fresh smelling and clean so as to avoid all patients breathing in this miasma and all getting sick.
Germ theory:
Disease is spread through small microbial organisms called germs. These germs, which can be bacteria, viruses, or other pathogens, should be able to be isolated from an infected host and then should no longer exist in the host's body when the host becomes healthy. Germs can move from one body to another through direct or indirect contact -- they can move through touching, spreading of fluids (coughing, sneezing, etc.) and potentially air, but not exclusively through the air.
During an epidemic, many people within the same area get very sick with the same disease and the air smells bad. How might a proponent of germ theory explain this?
The bad smell may or may not be related to the illness which was likely caused by the spread of germs, not by the bad smelling air.
All of these facts are in line with germ theory which supports a foul smelling vapor that spreads disease.
Sick people tend to smell bad as a natural way to warn other people to stay away.
Germ theory has no explanation for the cause of illness, only the best way to treat it.
Explanation
Germ theory suggests that diseases are spread by pathogens. Only one answer choice correctly states this theory.
Germ theory does not believe in a vapor; that's miasma.
The other two answer choices are completely irrelevant.
In the 19th century, there were two competing views as to how diseases spread.
Miasma theory:
Miasma (Greek for pollution) is a poisonous vapor that comes from rotting carcasses or other diseased bodies. It carries particles of the decomposing matter in it and spreads illness. This is why the bubonic plague spread so quickly in Europe: the air itself was foul-smelling and polluted with disease which caused everyone in the locale to become sick and die. It also explains why epidemics tend to originate in a certain area and infect everyone within that area -- they are all breathing in this noxious gas and getting the same disease. In hospitals, we need to ensure that the air is fresh smelling and clean so as to avoid all patients breathing in this miasma and all getting sick.
Germ theory:
Disease is spread through small microbial organisms called germs. These germs, which can be bacteria, viruses, or other pathogens, should be able to be isolated from an infected host and then should no longer exist in the host's body when the host becomes healthy. Germs can move from one body to another through direct or indirect contact -- they can move through touching, spreading of fluids (coughing, sneezing, etc.) and potentially air, but not exclusively through the air.
During an epidemic, many people within the same area get very sick with the same disease and the air smells bad. How might a proponent of germ theory explain this?
The bad smell may or may not be related to the illness which was likely caused by the spread of germs, not by the bad smelling air.
All of these facts are in line with germ theory which supports a foul smelling vapor that spreads disease.
Sick people tend to smell bad as a natural way to warn other people to stay away.
Germ theory has no explanation for the cause of illness, only the best way to treat it.
Explanation
Germ theory suggests that diseases are spread by pathogens. Only one answer choice correctly states this theory.
Germ theory does not believe in a vapor; that's miasma.
The other two answer choices are completely irrelevant.