Frogs and the similar toads are a large family of hundreds of species of batrachian amphibians, with a nearly worldwide distribution, absent only from high latitudes and remote oceanic islands. Even in deserts, species such as the water-holding frog, which is used as a drinking bottle by Australian Aborigines, are to be found, buried deep below the ground between the infrequent rains.
Frogs in Science
Frogs have often been the subject of scientific experiment, whether in high school science class dissections or Voltaire's 1766 experiments, in which he discovered that frogs hear with their legs. The discovery that a frog's leg will kick if an electrical shock is applied to it was the scientific basis behind the reflex tests now common in doctors' offices.
Frogs have also been used as a model organism in the fields of molecular biology and genetic engineering. The large, easily manipulated eggs of the frog species Xenopus serve as ideal expression systems for over-expressing genes of interest or the expression of novel or mutated genes. Because of this, Xenopus were among the first species to have had their genomes sequenced after the completion of the human genome project, and they are some of the first animals to have been genetically engendered. An example of this is the expression of florescent-tagged genes that allow researchers to track the expression of a particular gene product (a protein) in the body and observe the changes in the gene’s expression during certain disease states. Liberal animal rights groups object to the use of frogs in this manner, despite the promises this technology holds for the development of new treatments for human diseases. Environmentalists warn that release of these genetically modified frogs into the wild may cause detrimental effects on the environment and its native species; however, strict regulations exist aimed at preventing accidental release of genetically-modified frogs into the wild. These frogs are also extremely expensive to produce, thus the most likely means of release of such a frog into the wild would not be by accident but would instead be the result of theft.
Frogs in the Bible
The second of the Ten Egyptian plagues was of frogs. In Egyptian culture, frogs were gods, and worshiped as such. God released enough frogs from the Nile so that the Egyptians could scarcely avoid stepping on them, as a direct affront to this worship practice.
Leviticus declares them unclean to eat.
And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of any living thing which is in the waters, they shall be an abomination unto you. Leviticus 11:10 (KJV)
According to atheistic biologist Richard Dawkins, the joints of the Lesser Spotted Weasel Frog continue to present a challenge to the Theory of Evolution insofar as their origin cannot be explained by gradual degrees.
Frogs and toads
Both frog and toad are amphibians which hatch from eggs. A frog's skin is smooth and slimy, while a toad's skin is dry and bumpy. A frog has much longer legs which help it jump. A toad walks. 
- Water holding frog, South Australia Environmental Protection Agency 2004, accessed 26 May 2007
- Exodus 8:1-15
- God's Gift to Kansas, Committee for the Scientific Investigation of Claims of the Paranormal 2005, accessed 16 May 2008