Blood

Readers beware: today’s post is not for the faint of heart. If you don’t mind a little blood, then why not learn a little more about it.

Blood is a bodily fluid that plays several vital functions in animals. While humans have several types of blood cells, more than half is plasma – a solution primarily composed of water that also contains floating proteins. In addition to circulating the body’s blood cells, Plasma also distributes sugars and hormones, and removes waste such as carbon dioxide, urea, and lactic acid. Plasma also contains platelets (or thrombocytes), which form blood clots at wounds and cuts to preventive excessive bleeding.

Horseshoe Crabs

In observance of beach season, today’s post honors one of the sea shore’s oldest inhabitants: the horseshoe crab.

Horseshoe crabs date back to the Ordovician Period, and haven’t really changed in the intervening 450 million years; these ancient origins have earned them living fossil status. With their hard, dome-shaped shells, horseshoe crabs look like fossils; they molt this armor about 18 times over their life to keep growing. Under the shell, they have five pairs of clawed legs that converge at a central mouth. Instead of teeth, their mouths sport stiff bristles for eating mussels and worms.