Physiology 9: Changing environments Flashcards
What are the consequences of changing environs to animals?
Physiological adaptations under past environs may not be beneficial under future climates
They may lack appropriate physiological adaptations for new conditions
What is the Topt on a thermal performance curve?
optimum temp at which organisms have optimum performance
What is the CTmin / CTmax on a thermal optimum curve?
range of temps an organism can tolerate (performance drops to these points)
What happens to an organisms performance below their thermal optimum?
can survive below thermal optimum, but expending energy to warm themselves = performance decreases
What happens to an organisms performance above their thermal optimum?
Really energetically costly, esp at high temps where sweating etc. aren’t particularly effective, so performance declines readily
Why do endotherms have a wider performance optima than ectotherms?
Bc endotherms can regulate their body temps
Describe the study into calculating the upper thermal neutral zone of birds and mammals.
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
How can pop.s respond to changing environs?
- Can move either North or South to stay within temp ranges they are adapted for
- Can move towards higher altitudes
- Temporal changes
- Phenotypic change
What are the barriers to organisms moveming in response to changing environs?
- 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
What are temporal changes?
Changes in the timing of biological events
e.g
Butterfly emergence
Egg laying
Migration
Describe the thermal melaninism hypothesis in Springboks
Black individuals increased absorption of solar radiation
= advantageous in cooler temps
In warmer temps this is not advantageous - decrease in black individuals
What do increasing temps mean for ocean O2 conc.?
decreasing O2 levels
What are fishes responses to increasing global temps?
They must increase their metabolic rate increases as environ temp increases = O2 requirements increase, but decreasing O2 levels in the ocean
= decreasing body size
Why are tropical species most affected by chaning environs?
Closer to thermal tolerance limits
Evolved under relatively stable environ conditions
What is one way to mediate the impacts of environ change?
Heterogeneous habitats