The header images are all related to Drosophila:
Above: These are the giant polytene chromosomes found in a variety of tissues in Drosophila – these are from the salivary gland cells of the third instar larva. Calvin Bridges (see picture of the fly lab below) devised maps based on the banding patterns of these chromosomes – maps still in use today.
Above: A close-up image of a small area of a Drosophila wing blade. Each cell on the wing blade bears a single hair. This wing is from a fly that is heterozygous for a recessive mutation, multiple wing hairs (mwh), that causes each cell to bear a tuft of bristles. You can see some of the cells show this phenotype: these have resulted from an event that has made these cells homozygous for mwh – we have used this to assess the function of a Drosophila homologue of the human locus WRN, mutation of which causes a progeroid condition. See our recent publication.
Above: This a part of a photo showing members of the Morgan fly lab in the early 20th century. Those pictured are (from left to right) Edgar Anderson, Alexander Weinstein, S.C. Dellinger, Calvin Bridges, an "hooured guest", H. J. Muller and T. H. Morgan. The occasion pictured is to celebrate Alfred Sturtevant‘s demobilisation in 1918 (he can be seen in the whole image).
Above: The beast itself – this is a photograph of a male Drosophila melanogaster.
Above: The Drosophila eye is typical of insects: a compound eye composed of numerous facets – this is a scanning electron micrograph showing some ommatidia and bristles in the Drosophila eye.