Radiocarbon dating before present
They have moist scaleless skin which is used to supplement the lungs in gas exchange.
The eggs are soft and vulnerable to drying, therefore reproduction commonly occurs in water.
antibiotic resistance: A heritable trait in microorganisms that enables them to survive in the presence of an antibiotic.
Within a population there may be many different alleles of a gene; each has a unique nucleotide sequence.The term can also be applied to larger groups of organisms, as in "the adaptive radiation of mammals." adaptive strategies: A mode of coping with competition or environmental conditions on an evolutionary time scale.Species adapt when succeeding generations emphasize beneficial characteristics.Peaks on the landscape correspond to genotypic frequencies at which the average fitness is high, valleys to genotypic frequencies at which the average fitness is low. adaptive logic: A behavior has adaptive logic if it tends to increase the number of offspring that an individual contributes to the next and following generations.If such a behavior is even partly genetically determined, it will tend to become widespread in the population.