Essays for Unit 1 Flashcards
(35 cards)
The Scientific Method
The scientific method is the basis for empirical research through which one can formulate an understanding of a specific idea.
The Scientific Method’s Process
Goes as follows: making an observation, formulating a hypothesis (asking a question), performing an experiment (collecting data and making observations), and drawing a conclusion (evaluating data).
Example: The Scientific Method
I observe that my spaghetti tastes bland.
I hypothesize that it tastes this way because I didn’t add any salt/pepper to the sauce.
I experiment by adding salt/pepper, or other condiments, to the sauce and re-taste the spaghetti.
I conclude, presuming the spaghetti is no longer bland, that the sauce did not have enough seasoning.
NOTE…this particular experiment was NOT controlled.
A hypothesis is a proposed…
explanation of a phenomenon; it is an ”educated guess”.
A theory is a supposition of…
ideas intended to explain something.
A hypothesis may become a theory if…
it is tested multiple times and consistently yields the same result.
Hypotheses and theories can
never be proven. They can be supported (as true) or disproven (as false).
Controlled Experiment
A controlled experiment is one in which a group, or component, involved in the study is not exposed to the research variable. Thus, this is the “control” group (often called the “placebo” group). The other group, that is exposed to the variable, is the “experimental” group.
Variable
A variable refers to any factor or condition that can be changed or manipulated in an experiment. It is a value that is expected to change as a result of an experiment and represents the factor, or factors, that is being tested.
Independent Variable
An independent variable is one that the researcher can alter, ex. amount of food, amount of water, amount of light, degrees of temperature, amount of exercise, times of day, etc.
Dependent Variale
A dependent variable is one that relies on, and is affected by, the independent variable, and is not manipulated by the researcher, ex. amount of growth, state of disease, age of death, etc.
The use of variables (controlled, independent/dependent, etc.) is important because…
they ensure that the data collected from the experiment is due to the presence, or absence, of the variable(s) and not some other unknown influence.
Example: The use of variables
A researcher wants to test the effects of a new allergy pill.
He has a sample of people willing to participate in the study. He divides the group in half. Unbeknownst to them, one group will be given the actual drug (experimental group) and the other group will be given a sugar pill (control group). (Incidentally, this is called a “blind” study, because the groups don’t know which one they are taking. A “double blind” study is when the researcher doesn’t know either.)
Independent variables may include: sex of the participant, dosage of the pill, quantity per day, type of allergy the participant suffers from, etc.
Dependent variables may include: amount of runny nose secretions produced, duration of itchy eyes, area on the body where redness occurs, etc.
The Cell Theory
Cells are the fundamental units of all living things.
Deconstruct: The Cell Theory
- All organisms are made up of at least one (unicellar) or more (multicellular) cells.
- Cells come from other cells.
- Cells use materials and energy.
The Gene Theory
Genes are hereditary units composed of DNA (or RNA).
Deconstruct: The Gene Theory
- All organisms have genetic traits they received from one (asexual), or both (sexual), of their parents.
The Theory of Homeostasis
Individual cells, and complex organisms, have an internal environment that they can regulate so that it stays relatively constant. In other words, they have the ability to monitor and alter any internal changes that may cause harm.
Deconstruct: The Theory of Homeostasis
Organisms can respond to stimuli, ex. changes in environmental temperature, and either sweat or shiver to maintain their core body temperature.
The Theory of Ecosystems
Organisms forms groups in which they interact with biotic (living) and abiotic (non-living) components of the environment.
Deconstruct: The Theory of Ecosystems
Biotic relationships include interactions with other members of the same species (two humans), different species (humans and dogs), and different kingdoms (humans and trees).
The circle of life: producers -> consumers -> decomposers -> producers, etc.
The Theory of Evolution
Some organisms share the same, or similar, physical characteristics because of common ancestors.
Deconstruct: The Theory of Evolution
Humans and monkeys have many similar features because they are both primates.
Evolutionary relationships help to group, or classify, organisms: domain (least specific), kingdom, phylum, class, order, family, genus, species (most specific).
Characteristics of a Virus
- Non-living
- Non-cellular
- Genome is composed of DNA or RNA, single-stranded or double-stranded
- Require a host cell (usually a bacteriophage) to reproduce
- Very tiny, 0.2-2 micrometers in size
- Covering is a capsid and a membranous envelope (“naked” viruses lack an envelope)
- Viruses are categorized by their size and shape, type of genetic material (DNA vs. RNA), and presence/absence of an envelope.
