Physiology 9: Changing environments

Question 1

What are the consequences of changing environs to animals?

Answer 1

Physiological adaptations under past environs may not be beneficial under future climates

They may lack appropriate physiological adaptations for new conditions

Question 2

What is the Topt on a thermal performance curve?

Answer 2

optimum temp at which organisms have optimum performance

Question 3

What is the CTmin / CTmax on a thermal optimum curve?

Answer 3

range of temps an organism can tolerate (performance drops to these points)

Question 4

What happens to an organisms performance below their thermal optimum?

Answer 4

can survive below thermal optimum, but expending energy to warm themselves = performance decreases

Question 5

What happens to an organisms performance above their thermal optimum?

Answer 5

Really energetically costly, esp at high temps where sweating etc. aren’t particularly effective, so performance declines readily

Question 6

Why do endotherms have a wider performance optima than ectotherms?

Answer 6

Bc endotherms can regulate their body temps

Question 7

Describe the study into calculating the upper thermal neutral zone of birds and mammals.

Answer 7

Looked at maximum environ temps
Plotted difference between these Currently 15% of birds species and 16% of mammals are experiencing max ambient temps above upper thermal tolerance
Predicted to rise 36% of birds and 47% of mammals by 2080

Question 8

How can pop.s respond to changing environs?

Answer 8

• Can move either North or South to stay within temp ranges they are adapted for
• Can move towards higher altitudes
• Temporal changes
• Phenotypic change

Question 9

What are the barriers to organisms moveming in response to changing environs?

Answer 9

• Dispersal ability
  Might not be able to physically make the journey e.g wings too small
• Habitat availability
  Food availability
  Issues with competition
  Experience new selection pressures (species dynamics)
• Connectivity

Question 10

What are temporal changes?

Answer 10

Changes in the timing of biological events
e.g
Butterfly emergence
Egg laying
Migration

Question 11

Describe the thermal melaninism hypothesis in Springboks

Answer 11

Black individuals increased absorption of solar radiation
= advantageous in cooler temps
In warmer temps this is not advantageous - decrease in black individuals

Question 12

What do increasing temps mean for ocean O2 conc.?

Answer 12

decreasing O2 levels

Question 13

What are fishes responses to increasing global temps?

Answer 13

They must increase their metabolic rate increases as environ temp increases = O2 requirements increase, but decreasing O2 levels in the ocean

= decreasing body size

Question 14

Why are tropical species most affected by chaning environs?

Answer 14

Closer to thermal tolerance limits
Evolved under relatively stable environ conditions

Question 15

What is one way to mediate the impacts of environ change?

Answer 15

Heterogeneous habitats