Life Through Time

Question 0

Age of The Earth

Answer 0

4.6 Billion years ago

Question 1

Start of The Universe?

Answer 1

13.7 Billion years ago.

Question 2

Radiometric dating?

Answer 2

Requires the presence of radioactive isotopes present in minerals.

Question 3

Isotope

Answer 3

Same element with different number of neutrons.

Question 4

Stable Isotopes

Answer 4

Present in environment.

Question 5

Radioactive Isotopes?

Answer 5

Not stable and once formed will immediately decay into stable Isotopes.

Question 6

What are the four Geologic Time Scales?

Answer 6

Eons.
Eras.
Periods.
Epochs.

Question 7

Precambrian Time:

Answer 7

○ Accounts for 88% of geologic time
• Micro-continents form and are tectonically active
○ Formation of early supercontinent
○ Abundant volcanism
• Atmosphere and oceans form
• Yet entire time period is dominated by very simple life
○ Prokaryotic single-celled organisms

Question 8

First life appears?

Answer 8

3.8 billion years ago

Question 9

Early Paleozoic AKA?

Answer 9

Age of invertebrates.
Or aka Cambrian explosion(great diversity of life.)
All life confined to marine environment (multi-cellular life dominated)

Question 10

Middle Paleozoic:

Answer 10

Age of fishes.
Appearance of modern day fish, flightless insects & sharks.
Plants first to leave marine environment(waters).
Placoderm first marine predator.

Question 11

Late Paleozoic:

Answer 11

Age of amphibians.
Creation of last super continent Pangea.
Largest extinction event @ the end of the Permian period.

Question 12

Carboniferous

Answer 12

Mississippian and Pennsylvanian periods

Question 13

Therapsids

Answer 13

Mammal like Reptiles.

Question 14

Early Mesozoic

Answer 14

Mass extinction at the end of the Permian allowed for an adaptive radiation of reptiles
• Dinosaurs are not yet present
○ They will evolve from the early reptile forms
• Marine and flying reptiles dominate
○ Early ancestors of the crocodiles appear

Question 15

Middle & late Mesozoic

Answer 15

Dinosaurs dominant
○ Over 9000 species identified on every continent
• Appearance of the first angiosperms (flowering plants)
• Appearance of first birds and mammals
○ First birds evolved from reptiles
○ Mammals tended to remain small until the cenozoic