Browse "Nature & Geography"

 Only about 5% of the Earth's crust is composed of sedimentary rocks, but they cover 70-75% of the exposed surface and contain many economically important minerals, as well as coal and petroleum.

The common feature uniting seed plants is the "seed habit," a unique method of sexual reproduction. In all vascular plants, the conspicuous plant is a spore producer (sporophyte) that alternates, in the life cycle, with a sexual phase (gametophyte).

A shark is a marine fish with cartilaginous skeleton belonging to subclass Elasmobranchii, class Chondrichthyes, order Pleurotremata.

The shearwater (order Procellariiformes, family Procellariidae) is a medium-sized seabird.

Shooting Star (genus Dodecatheon) is a perennial herbaceous plant of Primulaceae family (primrose).

Shrew (Soricidae), family of small insectivores represented today by approximately 250 species worldwide, 16 in Canada.

Shrike is the common name for the family Laniidae of singing birds.

Shrimp are decapods ("10-footed") crustacean, differing from other decapods in being adapted for swimming, a fact reflected in the large, laterally compressed abdomen and well-developed pairs of swimming legs.

Silica, or silicon dioxide (SiO2), occurs as the MINERAL quartz and is the most abundant mineral of the Earth's crust. It also occurs in the skeletal parts of some animals (eg, certain protozoa) and various plants.

Important producing countries now are Mexico, Peru, the Commonwealth of Independent States, the US, Canada, Australia, Chile, Poland and China. Photographic films and papers account for about 25% of the demand for silver.

Silviculture is the branch of FORESTRY that deals with establishing, caring for and reproducing stands of trees for a variety of forest uses including wildlife habitat, timber production and outdoor recreation.

 The skunk is a carnivorous, cat-sized mammal. Skunks were previously considered as part of the weasel family (Mustelidae) but DNA research has placed them in their own family, Mephitidae.

The sky appears its deepest blue when the air is dry and clean. Water vapour and dust scatter all colours of light, causing the blue to appear washed-out and pale.

Slug is a common name for several terrestrial pulmonate and numerous marine gilled species of gastropod molluscs conspicuous by the lack of an exposed shell.

Smelt (Osmeridae), family of small, iridescent fishes of class Osteichthyes, found in coastal seas, streams and lakes of the northern hemisphere.

Snail, common name for members of several groups of gastropod molluscs. Snails inhabit all moist habitats, but most forms are marine.

A snake is a long, slender reptile of the suborder Serpentes, order Squamata (which also includes lizards). In Canada, 26 species and one hybrid are native. Most species are found in the southern part of the country.

Snipe is the name given to 19 species of small to medium-sized shorebirds (254-406 mm) of the sandpiper family.

The size of a snowflake is related to how far the snowflake has fallen from the sky and to how well colliding snow crystals stick to each other. The largest snowflakes are usually observed near 0° C because of the increased forces of adhesion at these temperatures.

Soapstone's use dates back to antiquity: early Egyptians carved it into scarabs and seals; in China and India it was used for ornaments, implements and domestic utensils. It was similarly used at various times over the past 7,500 years by First Nations, Inuit and Norse in Canada (see Inuit Art).