Silk

2012-01-11T04:36:00.000-08:00

Silk is a natural fiber made up of proteins. Although it is produced by several groups of insects, currently only the silk produced by larvae of Bombyx mori is used in manufacturing textile industry. There has been some research looking for other types of silks with different properties, which differ at the molecular level. In general, the silks are produced mainly by insect larvae before they complete their metamorphosis , but there are also cases of silks produced by adult. The secretion of silk is especially common in arthropod genus Hymenoptera (bees, wasps and ants), and is sometimes used in nest building. Other types of arthropod produce silk also, notably various arachnids such as spiders (see spider fabric ).

Bird

2011-07-12T00:51:00.001-07:00

Birds (class Aves) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. Around 10,000 living species makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich. The fossil record indicates birds evolved from theropod dinosaurs during the Jurassic period, around 150–200 million years (Ma) ago, and the earliest known bird is the Late Jurassic Archaeopteryx, around 150–145 Mya (million years ago). Most paleontologists regard birds as the only clade of dinosaurs to have survived the Cretaceous–Tertiary extinction event approximately 65.5 Mya.

sedadelsur

Silk

Bird