wk 5 DQ: discussion questions attached

Select 3 of the following questions and compose a cited 200- 300 word
response. Each response must have a unique academic citation.
1. As discussed in the Biology and Society section, burning biomass to
produce electricity avoids many of the problems associated with
gathering, refining, transporting, and burning fossil fuels. Yet the use
of biomass as fuel is not without its own set of problems. What
challenges might arise from a large-scale conversion to biomass
energy? How do these challenges compare with those encountered
with fossil fuels? Which set of challenges do you think is more likely
to be overcome? Does one energy source have more benefits and
fewer costs than the others? Explain.
2. Many infertile couples turn to in vitro fertilization to try to have a baby.
In this technique, sperm and ova are collected and used to create
eight-cell embryos for implantation into a woman’s uterus. At the
eight-cell stage, one of the fetal cells can be removed without causing
harm to the developing fetus. Once removed, the cell can be
genetically tested. Some couples may know that a particular genetic
disease runs in their family. They might wish to avoid implanting any
embryos with the disease-causing genes. Do you think this is an
acceptable use of genetic testing? What if a couple wanted to use
genetic testing to select embryos for traits unrelated to disease, such
as freckles? Do you think that couples undergoing in vitro fertilization
should be allowed to perform whatever genetic tests they wish? Or do
you think that there should be limits on what tests can be performed?
How do you draw the line between genetic tests that are acceptable
and those that are not?
3. The human body has not changed much in the last 100,000 years, but
human culture has changed a great deal. As a result of our culture, we
change the environment at a rate far greater than the rate at which
many species, including our own, can evolve. What evidence of rapid
environmental change do you see regularly? What aspects of human
culture are responsible for these changes? Do you see any evidence of
a decrease in the rate of human-caused environmental changes?
4. Mammals have a four-chambered heart, with two ventricles and two
atria. So do birds, alligators, and crocodiles, but other living reptiles
have a three-chambered heart, with just one ventricle. Paleontologists
debate whether dinosaurs had a three-chambered or a four-chambered
heart. Long-necked sauropod dinosaurs could have had unusual
circulatory demands because their head may have been raised far
above their heart. The farther the head is above the heart, the greater
the systolic pressure needs to be for blood to reach the brain. For
example, the long-necked dinosaur Brachiosaurus may have carried its

head as much as 6 m (20 ft) above its heart. It is estimated that such
an anatomy demanded a systolic blood pressure of 500 mm of
mercury for blood to reach the brain! Some paleontologists consider
this evidence that dinosaurs had a four-chambered heart that supported
a dual circulatory system similar to that of birds and mammals, rather
than the three-chambered heart of most nonbird reptiles. Can you
explain why?

5. Design a laboratory experiment to measure the effect of water
temperature on the population growth of a certain phytoplankton
species from a pond.

Additional Requirements 

Level of Detail: Only answer needed 
Other Requirements: see attachment