Biology
Discussion Tables
BIOL 103
Discussion Board Forum Prompt
Topic: Science as a Way of Knowing
Here are 5 scientific activities:
1. Measuring Oxygen Consumption during Respiration in Germinating Peas
a) We are curious to know what effect an abnormally high temperature will have on pea seedling germination.
b) Five grams of normal germinating peas are placed into 3 respirometers capable of measuring oxygen utilization. Respirometers are held at 25 C (room temperature).
c) Measurements of gas volume reduction are taken every 5 minutes for 20 minutes.
d) The total volume of oxygen consumed is calculated and averaged over the 3 respirometers.
e) The experiment is repeated with 3 respirometers held at 40 C, and three more held at 25 C.
f) Results are compared and the data are interpreted to conclude that 40 C temperature inhibits respiratory activity in germinating pea seedlings.
2. Evolution of Foraminiferan Shell Structure Over Time
a) We are curious to know what effect environmental forces over time will have on the structure of the shells of a Foraminiferan (foram) species. Forams are microscopic protists with shells.
b) We get permission to examine a 100-foot long coring sample from the ocean floor. Specimens are placed under an automated light microscope equipped with a computer.
c) The computer program uses measurements of shell shape to automatically sort and find individual shells of the species we are searching for. Photographs of these shells are arranged in a vertical sequence from the top of the column to the bottom. Shells of the species are seen to vary in shape from the bottom of the core column to the top.
d) Radiometric dates for fossil shells from both ends of the sequence are collected. These dates are from igneous rock formations near where these foram fossils were unearthed on land.
e) Three different coring experiments are sampled to confirm a neat, gradual progression from within the species from one older morph to a newer more modern morph.
f) Results are interpreted to conclude that this foram speciesshape evolved gradually and significantly over a period of 30 million years.
3. Accurate Free-hand Representation of Animals from 9 Major Animal Phyla
a) We are curious to know what a few representative members of the 9 major animal phyla look like.
b) A collection of YouTube video clips are examined to observe structures, coloration, movement, and in some cases, habitats of the representation organisms.
c) Video clips are paused while the organisms are drawn using pencils and paper. Structures within these drawings are then labeled, the organisms are named scientifically, assigned to their correct animal phylum, and then photographed and submitted to a course site for evaluation.
d) Drawings are evaluated by the instructor for accuracy of structural rendering, labeling, and correct naming and classifying of the organism.
e) This observation, drawing, labeling, and naming is completed for each of 9 individual animal species.
f) A score will be assigned by the instructor based on the quality of the 9 drawings with their corresponding labelling and naming.
4. Determining the Origin of Man using mitochondrial DNA
a. We are curious to know if the wide diversity of types of human beings alive today can be traced back to a single original man and woman as biblical texts suggest.
b. DNA from the mitochondria (a cellular organelle) of 150 humans from a variety of ethnic groups is degraded into small 150 base pair segments which are then amplified and sequenced.
c. The sequences are given to a computer program which uses overlapping regions of DNA sequence to order the segments and generate complete mitochondrial DNA sequence.
d. Rates at which mitochondrial DNA mutates are estimated. Knowing these rates and comparing mitochondrial DNA sequences from different human populations, a single common ancestral sequence can be deduced. The amount of time it took for that sequence to generate all the sequences that exist today can also be deduced.
e. Variations in mitochondrial DNA sequence can then be examined from a different collection of ethnic groups and the results compared with other such studies.
f. Computer comparisons using estimated mitochondrial DNA mutation rates suggest that all humans descended from a single woman living in Africa less than 150,000 years ago.
5. Determining the Best Cooking Oil to Use
a. We are curious to know which cooking/salad oil is best for human health. Individual chemical characteristics of various oils commend each of them to us. Which one is ultimately the most healthful?
b. We select subjects in order to randomize factors such as age, sex, and race. Each subject is paid $300 to participate in the test. Each undergoes an initial angiography study to determine a baseline level of plaque build-up in their blood vessels. The study requires the individual to consume only food prepared using one of four oils: corn, rapeseed (Canola), olive, coconut, or other non-fat foods. The restrictions last 1 year. A terminal angiography is then performed.
c. Data will be quantitative values taken from angiogram scans following computer analysis. Percent occlusion values will be determined before and after the dietary regime.
d. Comparisons will be made on before and after values using statistical analysis to search for any significance in the data.
e. The study will then be repeated using the same oils but for only a 5 month period of time.
f. Statistically significant differences will be used to determine which oil is preferable for use in order to promote circulatory system health.
Classify these 5 activities above using the following table:
Activity #
Classification
One max-10 word Quote (supporting your classification)
Value
(E,H or NS)
(Example): “We are curious to know…”
(MU or L)
1
2
3
4
5
E = empirical science, H = historical science, NS = non-scientific, MU = most useful, L = limitations
a) In the Classification Column indicate by letter: Which of these activities is empirical science? Which of these activities is historical science? Which does not represent scientific activity of either sort.
b) For any activity you labeled as empirical, list 1 brief phrase, quoted from the activity itself that best supports your choice. That is, the phrase you select should make it clear that, “This is an empirical study.”
c) From among the 5 activities, select the activity that best demonstrates the power and value of the Scientific Method. Place the letter MU in the last column opposite that activity. Select the activity that best demonstrates the limitations of the Scientific Method. Place the letter L in the last column opposite that activity.
d) Select and copy your completed table. Enter the Discussion Board, Create (a) Thread, and paste your table into the message box that opens. Keep the thread open and read on:
e) Now consider the following table:
Value
Choices
Rationale
MU
L
f) In this table, give a 2-sentence/50-word maximum rationale for your choice of the most useful study (MU) and a 2-sentence/50-word maximum rationale for your choice of the study most clearly showing science’s limitations (L). Write both rationales using 60 words and then condense each to 50 words.
Submit your Discussion Board Forum Thread by 11:59 p.m. (ET) on Monday. In the following module/week, you will continue your participation in the Discussion Board Forum by replying to 2 peers’ threads.
