Earth Science Chapter 11 Lesson 1 Content Practice A

Geologic History and the Evolution of Life

Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term
is used only once.

                  1.  a subdivision of periods on the geologic time
scale

                  2.  the time line of Earth’s past

                  3.  is nearly 90 percent of Earth’s history

                  4.  the largest unit of geologic time

                  5.  Mass extinctions are caused by sudden changes
in this.

                  6.  the disappearance of many species within a short
time period

                  7.  Organisms are dependent on this for survival.

                  8.  provides evidence of meteorite impact

                  9.  blocks sunlight resulting in environmental
changes

               10.  the change in species over time as organisms
adapt to their environments

               11.  connects two continents that were once separated

               12.  separation of species due to a physical barrier

               13.  the earliest life-forms

               14.  the sudden evolution of new, complex life-forms

A.  Cambrian explosion

B.  environment

C.  eon

D.  epoch

E.  evolution

F.   fossil record

G.  geographic isolation

H.  geologic time scale

I.    iridium

J.   land bridge

K.  mass extinction

L.   Precambrian time

M.  single-celled
organisms

N.        volcanic activity