Transcript Conservation_and_climate_change_RIM

Conservation and climate
change
Give 3
consequences of
climate change
Genetic diversity
Evolution occurs through the process of natural selection in
which the fitter organism pass on their beneficial alleles
to their offspring.
This process requires genetic variation to exist within a
population
Without genetic diversity evolution cannot therefore occur
Threats to the genetic diversity of species include:
•
changes in the climate
•
increased levels of pollution
•
Emergence of new diseases
•
Arrival of new pests
The human impact on genetic
diversity
Humans affect the genetic diversity of habitats,
usually by reducing it.
As we reduce the size of natural populations we
also reduce the gene pool, the sum of all alleles
present in a population
The monocultures produced by modern agriculture
are a good example of this
In extreme cases this genetic erosion or loss of
genetic variation may lead to extinction
Climate change
If the climate changes then species will need
to either evolve or change their distribution
Current climate change
The big question is ‘ are these two trends related?’
Most serious scientists would say ‘yes’.
Evolution
Evolution requires genetic variation so if the
genetic diversity of a species has been
eroded this is less likely to happen.
Additionally, rapid climate change may occur
faster than it is possible to evolve
Change in distribution
A change in distribution might for example mean whole ecosystems
moving towards the poles if the planet got warmer
Tough on those organisms that already live there, there’s nowhere else
for them to go
Alternatively a species could gradually increase the altitude at which it
lives. This has been observed in populations of the golden toad in
the Costa Rican cloud forest Again, harsh on the species that
already live at the top of mountains.
Another problem is that populations may be forced to migrate out of
conservation areas such as national parks
Polar bears cannot go
further north if it
gets warmer
Upwardly mobile – the golden
toad of Costa Rica
Agriculture and climate change
Climate change may affect agriculture in a number
of ways
Higher CO2 levels may lead to more rapid
photosynthesis
Higher temperatures may lead to faster growth
rates
There may be longer growing seasons
Because water evaporates faster there may be
more rain and this may fall in different areas
Sea levels may rise so that growing land is lost
Genetic diversity of domestic plants
and animals
The genetic diversity of domestic plants and
animals is usually lower than in their
undomesticated counterparts
This means that they are vulnerable to climate
change as they cannot evolve
One solution may be to grow crops in different
areas, for example we could grow bananas in
the UK
Transgenic crops may allow plants to be grown in
areas to which they were previously poorly
adapted
Climate change and disease
Longer growing seasons may provide longer for
pest and pathogen populations to increase
Warmer temperatures may also make it easier for
pests and pathogens to overwinter
As crops are grown in new areas they may
encounter new pests and pathogens
All of these factors may reduce agricultural yield
Human diseases may also migrate, for example
the Anopheles mosquito that carries malaria
may be able to live in the UK again, as it did in
the middle ages