Earths History

Question 1

how old is the earth

Answer 1

4.6 billion years old

Question 2

what happened 3.9 billion years ago

Answer 2

the earth cooled and water condenses and fills oceans

Question 3

when was the precambrian era

Answer 3

4.6BYA - 544 MYA

Question 4

how many years ago do eukaryotic organisms appear

Answer 4

1.8 BYA

Question 5

when was the Paleozoic era

Answer 5

544 MYA - 245 MYA

Question 6

what happend during the first half of the paleozoic era

Answer 6

animals with backbones appear in the ocean and seeded plants appear on land

Question 7

what happened in the middle of the paleozoic

Answer 7

4 legged amphibians are on land

Question 8

what happened at the end of the paleozoic

Answer 8

reptiles begin to flourish on land

Question 9

when was the mesozoic era

Answer 9

245 MYA - 66 MYA

Question 10

what was the mesozoic famous for

Answer 10

dinosaurs and appearance of small mammals

Question 11

which era had the theorized meteorite that killed the dinosaurs

Answer 11

mesozoic era

Question 12

when was the cenozoic era

Answer 12

modern era

Question 13

when did the first primates appear

Answer 13

30 MYA during the tertiary period

Question 14

when did modern humans begin to appear

Answer 14

200,000 YA during the quaternary period

Question 15

what are fossils

Answer 15

any trace or remainds of an organisms that has been preserved by natural processes

Question 16

what are fossils used to determine

Answer 16

geography, environment, animals, plants, and behavior

Question 17

where are fossils found

Answer 17

sedimentary rock

Question 18

what is a trace fossil

Answer 18

marking left by an animal like a footprint

Question 19

what is a cast fossil

Answer 19

fossil in which mineral fill a space left by a decayed organism

Question 20

what is an imprint fossil

Answer 20

when a thin object falls into sediment and leaves mark when rock hardens

Question 21

what is a petrified fossil

Answer 21

when minerals penetrate and replace hard parts of an organism

Question 22

what are mold fossils

Answer 22

when organisms is buried in sediment and decays leaving an empty space

Question 23

what is an amber or ice fossil

Answer 23

when the entire organisms is trapped in tree sap or ice

Question 24

which layers are the oldest

Answer 24

the bottom layrs

Question 25

fossil dating can determine _______ of appearance and extinction

Answer 25

order

Question 26

what does radiometric fossil dating use

Answer 26

radioactive isotopes to date fossils

Question 27

how is appropriate age determined

Answer 27

by comparing the isotope to th eelement it decays into

Question 28

what is teh halflife of K-40

Answer 28

13 billion years

Question 29

what is the halflife of carbon 14

Answer 29

5730 years