A chicken embryo inside of an egg. By the 72 hour stage the heart is well developed and the somites, optic vesicle, tail and leg buds are visible. Fractal networks of blood vessels bring energy from the yolk and exchange carbon dioxide with oxygen in the allantois.
Diatoms and bacteria living on the shell of an isopod crustacean, seen with an electron microscope. The diatoms are about 40 micrometers in length, and the bacteria are about 1 micrometer in diameter. High Resolution.
Image Credit: James Tyrwhitt-Drake, UVic Microscopy Facility