By binding to certain glutamate receptors, D-cycloserine selectively enhances extinction, suppressing the effects of conditioned associations such as anxiety, addiction and phobias.
Last December scientists announced the probable extinction of the first mammal because of climate change: the white lemuroid possum, now gone from Queensland, Australia.
Evolution is regarded as a branching process, whereby populations are altered over time and may speciate into separate branches, hybridize together, or terminate by extinction.