Question | Answer |
What are the remains or prints of a dead organism that is usually found in rock layers? | fossils |
What is a fossil that is a hollow space in rock left by a dead organism? | mold |
What is a fossil that has the same shape as the original organism? | cast |
what is a fossil that shows an animal's activity? | trace fossil |
what is the unchanged remains of an organism or part of an organism called? | true form fossils |
what is a fossil that helps scientists date rock layers? | index fossil |
What are tiny bits of matter that settle in water called? | sediment |
What is rock that forms from the deposit of sediment, usually found in layers, called? | sedimentary rock |
Where would you find older rock layers -- at the top or the bottom? | at the bottom |
what type of rock are most fossils found in? | sedimentary rock |
what do index fossils give us clues to? | changes in earth's climate and surface, and the age of rock layers |
how old do scientists believe the earth is? | 4.6 billion years |
what are the four eras of earth's history? | Precambrian, paleozoic, mesozoic, and cenozoic |
in what era are fossils hard to find? | precambrian era |
In what era did the formation of the earth begin? | precambrian era |
which era is the longest? | precambrian era |
what era is known as "the age of ancient life"? | paleozoic era |
what era did trilobites live in? | paleozoic era |
when did the first air breathing animals appear? | paleozoic era |
Which era is known as "the age of the dinosaurs"? | mesozoic era |
when did we see the first small mammals? | mesozoic era |
when did the dinosaurs die out? | mesozoic era |
what era are we currently in? | cenozoic era |
when did humans appear? | cenozoic era |
what era experienced ice ages? | cenozoic era |