BIO 123 EXAM 2 ESSAY QUESTIONS AND ANSWERS
1. Use the first and second laws of thermodynamics to explain why each ecosystem needs a
continuous supply of solar energy.
The first law says that energy can not be created or destroyed. The second law says in any
energy conversion, some energy is wasted as heat; moreover, the entropy of any closed
system always increases. Energy flows through ecosystems in one direction, typically from
the sun, through photosynthetic organisms including green plants and algae, to herbivores,
carnivores, and decomposers. The ecosystem cannot produce energy from nowhere. They
must gather energy from another source, hence the sun. If solar energy were to be
removed then the plants and other producers would not be able to create the sugars that
they need for energy and creating important structural molecules.
2. Explain how deforestation (the cutting down of trees) of tropical rainforests plays a large
role in excess CO2 in the atmosphere
Rainforests are the natural cooling of the earths atmosphere. They keep moisture in the air
in the vast area of most intensive solar warming. The destruction of the tropical forest
reduces water stream and clouds at an enormous extent and destroys the whole global
system of cooling and balance, up to arctic and antarctic regions. This elimination of
natural cooling is the real reason for global warming.
3. Athletes in all sports focus on aerobic conditioning. Use your knowledge of aerobic cellular
respiration and lactic acid fermentation (anaerobic respiration) to explain why performance
is improved if more oxygen can reach the cells for longer periods of time due to excellent
conditioning.
In aerobic conditions, the body is able to get oxygen and use it to break down nutrients in
cellular metabolic processes to provide energy and to produce carbon dioxide as a waste
product. This is necessary to provide the energy needed for the body for effective exercise.
Under anaerobic conditions, the body gets little oxygen hence its resorts to the breakdown
of nutrients without oxygen which would yield lactic acid. Lactic acid is responsible for the
muscle cramps that are felt in an individual and hinder effective sports activities since it
makes one feel tired and causes muscle soreness.
1. Use the first and second laws of thermodynamics to explain why each ecosystem needs a
continuous supply of solar energy.
The first law says that energy can not be created or destroyed. The second law says in any
energy conversion, some energy is wasted as heat; moreover, the entropy of any closed
system always increases. Energy flows through ecosystems in one direction, typically from
the sun, through photosynthetic organisms including green plants and algae, to herbivores,
carnivores, and decomposers. The ecosystem cannot produce energy from nowhere. They
must gather energy from another source, hence the sun. If solar energy were to be
removed then the plants and other producers would not be able to create the sugars that
they need for energy and creating important structural molecules.
2. Explain how deforestation (the cutting down of trees) of tropical rainforests plays a large
role in excess CO2 in the atmosphere
Rainforests are the natural cooling of the earths atmosphere. They keep moisture in the air
in the vast area of most intensive solar warming. The destruction of the tropical forest
reduces water stream and clouds at an enormous extent and destroys the whole global
system of cooling and balance, up to arctic and antarctic regions. This elimination of
natural cooling is the real reason for global warming.
3. Athletes in all sports focus on aerobic conditioning. Use your knowledge of aerobic cellular
respiration and lactic acid fermentation (anaerobic respiration) to explain why performance
is improved if more oxygen can reach the cells for longer periods of time due to excellent
conditioning.
In aerobic conditions, the body is able to get oxygen and use it to break down nutrients in
cellular metabolic processes to provide energy and to produce carbon dioxide as a waste
product. This is necessary to provide the energy needed for the body for effective exercise.
Under anaerobic conditions, the body gets little oxygen hence its resorts to the breakdown
of nutrients without oxygen which would yield lactic acid. Lactic acid is responsible for the
muscle cramps that are felt in an individual and hinder effective sports activities since it
makes one feel tired and causes muscle soreness.
