Laboratory 1 - Scientific Method
how many body parts does a pillbug have and what are they?
3 head, thorax, abdomen
hypothesis, conclusion, or theory - the data show that trans fat intake raises cholesterol and contributes to heart disease
conclusion
which is made by a scientists following experiments and observations, a theory or a conclusion?
conclusion
what do we call the sample that lacks the factor being tested and goes through all the experimental steps?
control group
negative control
control group that is not exposed to the experimental treatment or to any other treatment that is expected to have an effect.
what do scientists call the information they collect while doing experiments or making observations?
data
what consists of a pillbug's diet?
dead organic matter
testing hypothesis
designing an experiment that will effectively test your hypothesis well-designed experiment with a control group and experimental group
why are detritivores important?
detritivores are an essential part of the food chain because they help to break down dead plant or animal matter they return essential nutrients to the ecosystem and helps to prevent a buildup of dead or rotting material that could spread disease and have other negative consequences they are a compost
formulating a hypothesis
develop a tentative explanation to account for the observation formulate a testable prediction based on the observation and your proposed explanation
what kind of skeleton does a pillbug have?
exoskeleton its exoskeleton consists of overlapping "armored" plates
hypothesis, conclusion, or theory - if a pillbug moves towards a substance, is it attracted to or repelled by that substance?
hypothesis
hypothesis, conclusion, or theory - if a pillbug travels 3 mm in 30 seconds, what is its rate of speed?
hypothesis
where are pillbugs commonly found?
in damp leaf litter, under rocks, basements or crawl spaces under houses, etc.
what is scientific theory?
in science, the word theory applies to a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations. making observations --> formulating a hypothesis --> testing hypothesis --> conclusion --> theory
what do scientists do first when they begin to study a specific topic?
make observations
making observations
observations of the natural world, research, literature, and/or examination of previous data
what is the difference between a theory and conclusion?
a conclusion is based on observations and experiments completed within a limited time frame a scientific theory is based on observations and experiments completed over an extended time frame - based on many conclusions collected from different scientists researching the same topic
what is a tentative decision about the outcome of an experiment?
a hypothesis
the head of a pillbug
bears compound eyes and two pairs of antennae (used to detect sensory stimuli from its environment)
the thorax of a pillbug
bears pairs of walking legs (7 pairs; 14 total) as well as gills for gas exchange (located at the top of the first five pairs)
the abdomen of a pillbug
bears uropods - sensory and defensive in function that project from the abdomen
why is it important to test a pillbug's response using one substance at a time?
because when testing each substance individually we can easily determine what substance cause a pillbug's specific reaction
what structures do pillbugs use for gas exchange, and what condition must these structures be in to function properly?
pillbugs use gills to breath if the pillbug dries out, its gills won't function properly and the pillbug can suffocate enable for them to breathe properly they must be in damp areas, like under a dead log - if they start to overheat and dry out pillbugs will roll into a ball to protect the remaining moisture on their gills
conclusion
results analyzed and hypothesis is said to be supported or rejected
data
results of an experiment
what is a pillbug's defense mechanism?
the "roly-poly" posture where they roll up into a ball to protect their underbelly as only their exoskeleton is exposed does not bite, sting or transmit diseases
pereon
the 2nd - 7th segments of the thorax
theory
well-tested explanation that unifies a broad range of observations an encompassing conclusion based on many individual conclusions in the same field
hypothesis, conclusion, or theory - all organisms are made of cells
theory
what is a roly-poly classified as?
a terrestrial crustacean detritivores - feeds mainly on decaying organic matter
what do scientists develop after many years of experimentation and a lot of similar individual conclusions?
a theory
why is a theory more comprehensive than a conclusion?
a theory is supported by numerous tests and evidences, a conclusion just answers one individual question
pillbug
armadillidium vulgare
cephalothorax
the head fused with the 1st segment of the thorax
why is it important to have a control substance for an experiment?
the presence of control groups allows researchers to confirm that study results are due to the manipulation of independent variables rather than irrelevant variables.
