Geologic Time

Relative dating can be used to determine

• how old a fossil is in years.

• how long ago a fossil organism lived.

• how long since two species diverged.

• which of two fossils is older than the other.

Molecular clocks are based on

• how old a fossil is in years

• eons, eras, and periods.

• major events in geology.

• positions of fossils in rock layers.

The longest units of time in the geologic time scale are

• eras

• eons

• periods

• super eons

The Precambrian lasted from the origin of Earth until about

• half a million years ago.

• 1 million years ago.

• 100 million years ago.

• half a billion years ago.

Miller and Urey’s famous experiment showed that

• the atmosphere of early Earth contained mostly oxygen.

• the first cells could have evolved from inorganic molecules.

• organic molecules could form under conditions on early Earth.

• Earth’s early atmosphere would have been toxic to life.

The RNA world hypothesis states that RNA

• was the last organic molecule to evolve.

• evolved before DNA or proteins.

• evolved from DNA.

• evolved from proteins

Major adaptations that evolved during the Precambrian include

• sexual reproduction

• specializations of cells

• multicellularity

• all of the above

The Mesozoic Era is known as the age of

• mammals

• dinosaurs

• birds

• fishes

The Linnaean system of classification consists of a hierarchy of groups called

• species

• taxa

• domains

• clades

What does a phylogenetic tree represent?

• the evolutionary history of a group of related organisms

• the pedigree of individuals within a particular family

• the most inclusive taxon of Linnaean classification

• the three-domain classification system