Sheri - Physiology (1,2,3)

Question 1

Complete the following by filling in the blanks. Spell out all words or phrases:

Oxidative stress is thought to be the major cause of DNA _____________ in aging males, through the stimulation of harmful _________________________
_________________ in the sperm mitochondria, resulting in a decline in sperm___________ and the ________________ of eggs. Oxidative stress may also threaten Antarctic ice fish as temperatures warm because they have ________________ mitochondrial density in their cells to cope with reduced oxygen consumption, due to the loss of ______________________ genes.

Answer 1

In aging males, oxidative stress is thought to be the major cause of DNA DAMAGE in aging males, through the stimulation of harmful REACTIVE OXYGEN SPECIES in the sperm mitochondria, resulting in a decline in sperm QUALITY and the FERTILIZATION of eggs. Oxidative stress may also threaten Antarctic ice fish as temperatures warm because they have INCREASED mitochondrial density in their cells to cope with reduced oxygen consumption, due to the loss of HEMOGLOBIN genes.

Question 2

Are tropical or temperate species most threatened by climate change? Which group will better tolerate increases in habitat temperature?

Answer 2

Tropical species live and warmer habitats and have evolved higher thermal tolerance but they have less variation in their range and they are already living at HMT (Habitat max temp) and LT50 (their thermal tolerance max). Temperature species have more range to adapt and lower LT50 with more range. But tropical species cant further acclimate or adapt to higher temperatures so they are at more risk to climate change.

Question 3

Explain CTmax and whether tropical or temperate species are more likely to be able to acclimate to warmer sea temperatures.

Answer 3

*Critical thermal maximum: (CTmax)
Temperature at which a physiological system collapses

*Tropical species less able than temperate species to increase CTmax after being acclimated to warmer temps

Tropical species may be more susceptible to acute thermal death in the face of increasing temperatures