FridayNovember 16,

2012(Quiz 12;

Complete Lab – The Geologic Time Scale)

The Launch PadFriday, 11/16/12

What are the names of the eons

if we consider there to have been only two in Earth’s

history?If the Earth is 4 500 millions years old,

how many years did each eon occupy?

What percentage of Earth’s history did each occupy?

The Precambrian Eon and the

Phanerozoic EonPrecambrian – 3958

million yearsPhanerozoic – 542

million years

Precambrian – 88%, Phanerozoic

– 12%

The Launch PadFriday, 11/16/12

Name an important factor that caused the

Precambrian Eon to change to the

Phanerozoic Eon.

First organisms with shells and other hard

body partsName an important

factor that caused the Paleozoic Era to change

to the Mesozoic Era.

Great Permian extinction

Name an important factor that caused the

Mesozoic Era to change to the Cenozoic Era.

Extinction of dinosaurs and many

other species

Announcements

Assignment Currently Open

Summative or

Formative?Date Issued Date Due Date Into

GradeSpeed Final Day

Quiz 10 S5 11/2 11/2 11/16Video Activity –

Fearless Planet – Earth Story

F1 11/6 11/9 11/16

Quiz 11 S1 11/9 11/9 11/30WS – Origin of the Atmosphere and

OceansF2 11/13 11/16 11/16

Lab – The Geologic Time

ScaleF3 11/14 11/16 11/16

Recent Events in ScienceScientists Discover Possible Building Blocks of Ancient Genetic Systems in Earth's Most Primitive Organisms

http://www.sciencedaily.com/releases/2012/11/121110093550.htm

Read All About It!

Scientists believe that prior to the advent of DNA as Earth's primary genetic material, early forms of life used RNA to

encode genetic instructions.

What sort of genetic molecules did life rely on before RNA?

The answer may be AEG, a small molecule that when linked into chains forms a hypothetical backbone for peptide

nucleic acids, which have been hypothesized as the first genetic molecules.

Synthetic AEG has been studied by the pharmaceutical industry as a possible gene silencer to stop or slow certain

genetic diseases.

The only problem with the theory is that up to now, AEG has been unknown in nature.

A team of scientists from the United States and Sweden announced that they have discovered AEG within

cyanobacteria which are believed to be some of the most primitive organisms on Earth.

Cyanobacteria sometimes appear as mats or scums on the surface of reservoirs and lakes during hot summer months.

Their tolerance for extreme habitats is remarkable, ranging from the hot springs of Yellowstone to the tundra of the

Arctic.

Quiz 12After you finish your Quiz, please complete your Lab

on the Geologic Time Scale.

Complete Lab- The Geologic Time Scale

Figure 11.19

The Geologic Time Scale