Scientists have measured changes in animals, plants and environments in relation to changing temperatures for decades. Some amount of fluctuation in temperature is normal, with some years being colder or warmer than others. Long-term measurements help scientists to figure out patterns in temperature fluctuations and determine when temperatures are deviating from trends. This is what we are seeing in recent atmospheric measurements – a strong increase compared to historical trends.
An example of adaptation to a change is the shift of some species northward based upon warmer temperatures, which can be seen in the map below. Birds are not traveling as far south as they once did because they have adapted to the increased temperatures at these northerly locales (see link and map below).
At the opposite end of the spectrum, numbers and ranges of the pika are shrinking in California due to increased temperatures (link). When temperatures increase, pika are not able to build nests and are confined to longer periods living underground. With decreased survival comes a decreased ability to pass on their genes through reproduction, causing a lack of genetic adaptation.
When animals or plants shift how they respond to temperature through physical changes, behavior or by moving, these shifts are referred to as “adaptation”. Genetic adaptation occurs when genes change either through (1) mutation and are passed along to offspring or (2) in frequency in populations (some genes are more abundant than others).
Animals and plants can have the adaptive response of surviving a change or can go extinct because they are not able to survive. The reason for this can be either phenotypic change (occurring during a plant or animal’s life because of adaptation) or evolutionary change (occurs over the course of generations due to changes in genes in populations). Evolutionary change with a particular cause is found more rarely, but this will likely change as we find out more about genes and how they respond to the environment (through more and better technology, like DNA sequencing).
In relation to climate and temperature, scientists have not been looking at genes for very long. DNA technology is fairly new, but scientists have had the ability to make observations about the phenotypes, or the observable features of species resulting from the interaction of genes and the environment, for much longer. But there is a long history of looking at patterns of where animal and plant species are distributed.
Sequencing an entire genome, that is, looking at the map of all of the DNA of a plant or animal at the individual level, is a very new technology. When scientists are able to look at the genomes of more animals and plants, we will be better able to determine how adaptation occurs at the genetic level and what genes might be correlated with adaptation to environmental change.