What is science?
A system that assembles and organizes information in the form of explanations that can be tested, as well as offers predictions about the world around us.
Systematic study of structure and behaviour of natural and physical world through observation, experimentation and testing of theories.
Explain the hierarchy of the sciences
The hierarchy of sciences describes the fact that the different branches of the sciences work closely and draw upon one another for support in corroboration.
What is the goal of science
To understand natural phenomena, and there are generally two types of overarching (based on the type of reasoning) inductive or deductive,
Describe inductive and deductive reasoning
Inductive reasoning refers to “discovery science” whereby observations are used to infer conclusions, but there is no complete certainty as to the validity of these observations. Deductive reasoning refers to hypothesis base science” whereby previously known premises are used to form conclusions, it is assumed that as long as the premises are correct the conclusions will be too.
Inductive reasoning happens in scientific investigations when a researcher makes empirical observations and from these examples comes up with a more general idea or model about how the world works. Here, Warren is starting with the observation that bacteria are often found at the site of peptic ulcers, and from this he is starting to formulate an idea about what causes ulcers. This is an example of inductive reasoning.
Deductive reasoning occurs when a scientist has a model, hypothesis, or theory about how the world works and designs experiments to test it out. At this point, Warren does not have a theory or hypothesis driving his research. He is only making observations. He is therefore not using deductive reasoning.
What is hypothesis based science?
“hypothesis science” whereby hypothesis’ are formed to explain the natural world and are then tested. Hypothesis’ tend to be an educated guess based on prior knowledge and observation, and may also include an explanation of why the guess may be correct.
What is a scientific hypothesis?
The initial building block of the scientific method. An educated guess based on prior knowledge and observation. It is a testable statement proposed to answer a question.
True or false, a hypothesis can be proven to be correct 100% of the time
False
Explain what the scientific method is and the steps involved
The scientific method is a process for experimentation that is used to explore observations and answer questions. It involves the following steps; observe, ask a question, conduct background research, form hypothesis, test hypothesis with an experiment, analyze data, draw conclusion, communicate results
Difference between theory and hypothesis
Theories are the result of a tested hypothesis. Hypothesis are ideas, theories explain the findings of the testing of those ideas
What is qualitative and quantitative data
Qualitative date are descriptive and not countable. Quantitative date are countable and usually have a numeric value (preferred for sciences as they are seen as more objective)
A pharmacist was told that a newly released itching powder was the best thing on the market, since it claims to cause up to 75% longer-lasting itches. Interested in assessing this new product, he buys the itching powder and compares it to his usual product. One test subject (X) is sprinkled with the original itching powder, and another test subject (Y) is sprinkled with the experimental itching powder. Subject X reports having itches for 35 minutes. Subject Y reports to have itches for 50 minutes.
Identify the (i) control group, (ii) independent (manipulated) variable, and (iii) dependent (responding) variable.
Explain whether the data support the claims about the product. Calculate the % increase in itching duration observed for the new product
i) subject with the original powder
ii) the type of itching powder applied
iii) the time the itch lasts
If 35 minutes is the base time with the original powder then the increase is actually lower than 75%. 75% of 35 is 26.25. which would me the new product would need to produce an itch of 61 minutes for it to be a 75% increase.. The current percentage increase is approximately 41%
Differentiate between study designs that investigate correlation and causation relationships.
Let’s say you wanted to investigate the “stress causes ulcers” hypothesis. Which among the following experiments would be the best way to demonstrate that stress causes ulcers? Why? (Be sure that you can explain your choice using causational relationships NOT correlation.)
Which hypothesis is correct:
A) I would follow a group of people for several years where I regularly give them surveys to assess their levels of perceived stress and monitor which among them develop ulcers.
B) I would gather data about the prevalence of ulcers among people in high stress jobs compared to those in low stress jobs.
C) I would tell a group of students in one course that they have been found guilty of cheating and will fail their degree—and I would monitor what proportion develop an ulcer. I would also monitor the students in another course where I told the students information about plagiarism in general.
I would collect data about the stress levels of a large group of nurses working at a hospital by taking blood samples and measuring their levels of cortisol (a stress hormone). I would plot their level of cortisol against the presence or absence of ulcers to determine the threshold amount of “stress” required to cause an ulcer
A B D are examples of causational relationships.
C) This is a controlled experiment where students have an equal chance of being assigned to each group and one variable was changed between the two groups (the level of stress induced) and monitored for the effect on the second variable, the development of ulcers. Note that this study is highly unethical and would not pass any research ethics board review. It is unethical because it would potentially cause psychological harm to the students (and possibly physical harm if the hypothesis is shown to be accurate and students develop ulcers), and it is unlikely that participants would have provided informed consent to participate in this study.
**This is a stupid example because we would imminently think about the ethics, so when questions like this come up don’t think about the practicality of it, just think of the study design.
Read case study slides and define what falsifiable hypothesis, dependent variable, independent variable, and control are (hint slide 19)
Falsifiable hypothesis - H. pylori causes peptic ulcers (or the null hypothesis that H. pylori does not cause peptic ulcers)
Dependent variable - The presence or absence of peptic ulcers
Independent variable - The bacteria H. pylori
Control - Absence of bacteria
What is phylogeny and evolution
Phylogeny is the study of the history of evolutionary organisms. Evolution is the change in characteristics of a species over generations which relies on natural selection.
What are the five shared characteristics of living organisms
- Made up of membrane-bound cells
- Are capable of replication
- Populations are continually evolving
- Process hereditary information encoded in gens as well as environmental information
- Acquire and use energy
Where did the first cell come from
Most likely arose from non-life due to chemical evolution. Transformations whereby simple organic molecules like amino acids and nucleotides were formed.
What is biology
The study of living things and the processes which support life
What is natural selection and what two conditions must be met for it to occur in a population
Natural selection is the theory that explains how evolution occurs. The two conditions that need to be met are; individuals must vary in characteristics that are heritable and certain versions of these heritable traits must aid in an individuals ability to reproduce more than other versions
Describe 4 key stages of natural selection
Variation - A natural variation in the characteristics of individuals that are apart of a population
Overproduction - ecosystem cannot support all life with the population creating competition
Selection - those more adapted individuals survive and those without the trait die off
Reproduction - those with the adaptation (trait) are able to reproduce and pass this trait on to their offspring, Over time the population will see a shift towards a higher number of the adapted individuals
What is speciation, fitness, adaptation and population
Speciation - occurs when populations diverge into new species
Fitness - the ability to produce offspring, those with high fitness produce more offspring
Adaptation - a trait that increases the fitness of an individual in a particular environment
Population - a group of individuals of the same species living in the same area at the same time
What are the five animal kingdoms
Protista, Fungi, Flora, Fauna (Eukaryotic), Monera (prokaryotic)
What are the three main branches of life in the phylogenetic tree of life?
Bacteria, Archaea and Eukarya
What is the replicator-first hypothesis
Replicator first refers to the first cells being from non life (chemical evolution) which lead to more complex structures which became enclosed in membranous structures to form the first cell.
What is the metabolism first hypothesis
Metabolic chemical reactions came first which developed before RNA or DNA
