Exercise 2.2: Why Is the World Full of Large Females?
Real World: Females incline to be larger than males in majority of species
Model: Females have larger body due to the significance of reproduction and offering protection immature ones
Prediction: Females have larger bodies so as to protect the young one
Data: Examining varied lizard species, Shrine examined the size of clutch of females and males to observe the disparities, but that was not only aspect that was different.
Negative Evidence: Yes, since the data and the prediction disagree
Positive Evidence: No, since there were numerous varied aspects that can validate the female larger or the male larger.
Exercise 2.3: Prions
Real World: Biologists are investigating whether protein alone in infectious agent can harm the victim or whether the agent must have DNA or RNA
Model: In mid-1970s, biologists believed that infectious agents must have genetic material made of nucleic acid (RNA or DNA) to multiply in their victims.
Prediction: Outbreak of Mad-cow disease in Great Britain which was believed to be caused by sheep, their disease scapie as ground-up sheep heads were found in commercial feeds for cows.
Data: Using extracts from the brain of scrapie victims containing protein alone, which were subjected to ionizing radiation and injected into brain of normal animal. The irradiated extracts produced scrapie. Other researchers used similar extracts without proteins and injected them to a normal animal, and they established that the treated extracts had reduced ability to cause scrapie.
Negative Evidence: Yes, the ionized extracts caused scrapie in healthy animals
Positive Evidence: Not clear as the treated extracts just reduced their ability to produce scrapie
Exercise 2.4: Identifying the Scrapie Prion
Real World: Determining why PrP can cause a disease to some animals while it’s harmless to others
Model: Isolating particular protein that cause scarpie (PrP)
Prediction: Prusiner recommended that there might be two kinds of PrP, one common and harmless, the other rare and deadly
Data: Isolated specific genes liable for production of PrP, discovering that victims of scarpie and allied illnesses had a slightly mutated version of the gene that produces normal PrP. Some produced low levels of the deadly PrP while others produced highly levels of the deadly version. Mice was used and it was discovered that mice with high level of deadly Prp die of disease similar to scarpie while those with low levels die of remain healthy.
Negative Evidence: No, since it was established PrP is produced naturally in many ways
Positive Evidence: Yes, it was confirmed that PrP appears in two forms, one common and harmless and the other rare and deadly. Mice with low level of scarpie remain healthy.
Exercise 2.5: HIV versus the Human Immune System
Real World: HIV regularly manages to defeat the immune system of the victim
Model: Virus population evolves in the surrounding in the immune system.
Prediction: Mutated viruses would get observable to those agents till they themselves gets adequately abundant to stimulate production of fresh immune system agents
Data: It is probable to obtain the genetic changeability of the virus population
Negative Evidence: No, since the data and the forecast disagree
Positive Evidence: Yes, the data and the forecast agree since they validated the way HIV takes over
Exercise 2.6: A Heresy in Evolutionary Biology
Real World: investigating some facts of evolutionary biology specifically the generation of gene mutations
Model: Natural selection is dual process
Prediction: There is generation of genetic mutations followed by the fixation of variants genes uninfluenced by external factors
Data: Using Escharicin cali incapable of metabolizing lactose and exposing them to the sugar
Positive Evidence: Yes, populations of bacteria have some way of producing
Negative Evidence: not clear
Exercise 2.7: Discovery Supports Theory That Meteor Caused Dinosaur Extinction
Real World: Determining reason behind extinction of dinosaur
Model: Noble Prize-winning model
Prediction: The falling of giant meteorite or comet slammed into the earth with the energy of a billion atomic bombs, which killed all dinosaurs in the world.
Data: Use of radio telescopes to measure density of observable galaxies
Positive Evidence: No, density of different galaxies differs indicating that the shock wave around different parts of the world cannot be the same
Negative Evidence: Yes, prediction and data disagree; the density is measured to decrease and cannot be the same everywhere
Exercise 2.8: The Expanding Universe
Real World: The world is expanding, since all of the galaxies are distancing from each other
Model: Steady state model; matter is formed and then moves externally. The explosion model; everything is strong and then moves externally
Prediction: Density of matter should be equal everywhere and density of the most far-away galaxies should be minimal if the explosion model is accurate
Data: There is an apparent reduction in the density of the most far-away visible galaxies
Positive Evidence: Explosion model, since the data has verified that the density is redistributed
Negative Evidence: Steady state since the density is not equally the same
Exercise 2.9: New Observation Reveal Cosmic Mystery
Real World: Determining what keeps stars together in the galaxy
Model: Milky Way model; the solar system and sun are one-third away from the edge of the galaxy. The standard model; that the starts are kept together by force of gravity model
Prediction: Galaxy has millions of stars with most near the middle and fewer out toward the edges
Data: Sharpening images produced by large telescope by use of computers
Positive Evidence: Milky Way Model-stars at the outer edge move faster than starts at the center
Negative Evidence: Standard Model-the difference in speed between stars at the center and at the edge makes it hard for force of gravity to hold galaxy together
Exercise 2.10: Scientist Put a New Twist on Creation of the Universe
Real World: Astronomers are carrying out a survey of radio sources and have found an object in the Leo constellation
Model: Einstein’s theory articulates that gravitational lensing would occur when waves or light pass something in the center forming rings.
Prediction: An image can only create a whole ring if a source and the lensing object are accurately matched with the earth
Data: Radio source of miniature elliptical of approximately two arch seconds across has occurred.
Positive Evidence: Yes, the prediction and the data agree with each other since a ring was created and they have precluded any other likelihood.
Negative Evidence: No, the prediction and the data agree
