Lecture 12 climate change and biodiversity Flashcards
How many cases did the world scientists raise concern about?
9, out of which only ozone depletion was reduced.
How is the climate changing?
- Temp is going up
- Hadley cells are churning further. over 30deg because of more heat, which sis causing the deserts to expand toward the poles
- Extreme weather events are becoming more frequent
- Local climate change is affecting organisms
What happens to organisms as the climate changes?
- Phenotypic Plasticity
- Adaptation
- Range shift
- Extirpation
What is phenotypic plasticity?
Acclimating to new conditions, this happens within the organism’s lifetime.
EX: if they were exposed to high temp early on, then they would develop more resistance to the temp
What is Adaptation?
Adapting to new climate, happens across generations
What is range shift?
Moving/ changing to a suitable location
What is extirpation?
Going extinct locally aka extirpations occurs when the other 3 cannot happen
What were the results from the porcelain crabs about how they acclimate?
Y axis: Critical temperature
When the crabs were reared at low temp, their critical withstanding temp became higher
While it didn’t change much with heat.
The result was that species can’t acclimate to everything we throw at them.
What was Mills et al’s question and how did they achieve this?
Question: Is there sufficient current plasticity in the initiation or rate of colour change to reduce mismatch and respond to change in snow cover?
They radio collored hares and performed weekly measurements of coat colour and snow around each hare.
What were the results form the study about hares?
Very little variation in when hares turn brown to white colour in fall over the 3 years
In spring, there was a bit more variation, in 2011 the hares waitied a bit more to turn brown
Overall, there was more variation in spring than in fall.
How does survival change with changes in the coat colour in hares.
X axis: % contrast (0 means white hare in a white background)
Y axis: Weekly survival
As the contrast increase the survival decreases
But at the current rate the lambda was over 1, the population was growing, but in the late century the mismatch alone can cause lambda to go below 1, causing decline in population.
Is it predicted to see if the hares will adapt?
There is currently not enough plasticity for hares to change colour of their fur.
In the furture the mismatch might increase, but natural selection will choose the hares that reduce mismatch.
What does the hares population depend upon to save themselves from extinction?
Amount and type of generic variation underlying the timing of coat colour change.
What did Andy Smith find about pika populations in the Great basin?
X axis: Mean min summer temp
Y axis: Mean summer (max) temp
grey dots (extant or currently living)
crosses: extirpated or Locally extinct
black dots: Signs that there were pikis living once upon a time but no longer living there.
Results: More dots at the top, which means pikas at the top were at risk of extinction in the summer
Are pikas going extinct?
In the great basin, the range of elevation is getting smaller. When temp went above 26 deg, they were in the lethal zones, hence they were threatened.
But the population was ding fine in other regions.
