What is a Keystone?

What is a keystone? You might think that all arches are made the same way. The fact is they are not all the same. Typical Roman arch with keystone. It is true that Egyptian, Babylonian, Greek and Assyrian civilizations used arches for underground structures such as drains and vaults. However, it was the Roman civilization (1000 B.C.E. - 500 C.E.) that first began using a keystone (also called a capstone) in their arches. The keystone is the topmost stone in the arch. The one in the illustration on the right is exaggerated in size from what a normal keystone would be.

This is an editable Google Doc version of a resource that is also available as an easy-to-print PDF. Keystone species are species that are more

What is a “Keystone Species”? (Online Reading Activity)

The keystone metaphor. The keystone is the component of a structure

KEYSTONE SPECIES A keystone species is a plant or animal that plays a unique and crucial role in the way an ecosystem functions. Without keystone species, - ppt video online download

Keystone Species - Sharks

Make Your Point

What Is a Keystone in Masonry?

ID Cards - Keystone First

Keystone species are species that are more important than others in an ecosystem. This means that the loss of a keystone can lean to drastic changes

What is a Keystone Species? (Online Reading Activity)

Keystone species, facts and photos

Keystone species, Predator-prey relationships, Ecosystem balance, Biodiversity

What is a Keystone?