lecture 1 - variance and scientific method Flashcards
organization of life (biggest to smallest)
- biosphere
- ecosystem
- communities
- population
- organism
- organ/system
- tissue
- cell
- organelle
- molecule
properties of life
- order (genetics)
- evolution
- response to environment (ecology)
- regulation (homeostasis)
- energy required (photosynthesis and cellular respiration)
- growth and development (eggs, sperm, new cells)
- reproduction (DNA)
regulation (homeostasis)
various mechanisms that act to prevent changes in the environment inside our bodies
what must you have to regulate internal environment?
receptor, control center, effector
1st law of thermodynamics
energy can be transferred or transformed but neither created nor destroyed
explain how energy is converted
input energy (ex: energy in the form of sunlight or food is taken up by organisms) - conversion process in organisms - heat & output energy (ex: all organisms convert input energy into heat and work - no energy is created or destroyed)
second law of thermodynamics
every energy transfer or transformation increases the disorder (entropy) of the universe
explain the idea of increasing disorder
- the effect YOU have PERSONALLY on your environment
- as monomers combine into polymers, entropy inside the cell decreases which requires energy. some of the energy is released as heat, increased the entropy in the enironment. total entropy of cell plus the environment increases
entropy
motion of molecules, “idea of increasing disorder”
scientific method
1- make a set of observations which lead to questions
2- specify biological question you are asking
3- put question in form of biological null hypothesis and alternate hypothesis with predictions
4- put question in form of a statistical null hypothesis and alternate hypothesis with predictions
5- determine which variables (data) are relevant to the question
6- determine what kind of variable each one is
7- design an experiment that controls or randomizes the confounding variables
8- based on the # of variables, the kinds of variables, the expected fit to the assumptions and the hypothesis to be tested, choose the best statistical test to use.
9- do the experiment.
10- apply the statistical test you chose, and interpret the results with regards to hypothesis
11- communicate your results effectively, usually with graph or table
when does a hypothesis become a theory?
when the hypothesis has been tested by many independent experiments (by many different labs) and it still holds up
what is the difference between quantitative and qualitative variables?
quantitative: numbers, measurements
qualitiative: discrete categories that can be expressed as a word (ex: gender, colour)
types of variables
independent (deliberately changed by the scientist) or dependent
little variability
small variance indicates that the data are cluttered tightly around the average
high variability
large variance indicates that the data are spread out (lots of different observations)
do we generally want small variance or large variance?
small variance - tightly, clumped together = better, stronger results
when is high variability beneficial?
for evolution, you want high variability to ensure survival (natural selection)
variance
distance from the mean of all the data points (how far a set of numbers are spread out)
equation - variance of entire population (used in nature)
σ^2 = Σ(xi-mean)^2/N
equation - variance of sample (used for labs)
s^2 = Σ(xi-mean)^2/n-1
experiment
procedure in which an observation or measurement is repeated on multiple individuals
true or false? conditions under which observation is made should be identical
true
what is each individual observation called?
a replicate
true or false? more replicates means better and more powerful your conclusions
true
what is pseudoreplication
testing something you’ve already tested
