fossils

Question 1

What are 2 ways we date earth’s events in history?

Answer 1

1. relative dating, 2. radiometric dating

Question 2

Fossils provide vital information about…?

Answer 2

extinct species

Question 3

Why is the fossil record incomplete throughout time?

Answer 3

Many organisms die without leaving a trace

Question 4

Researchers who study fossils are called?

Answer 4

Paleontologists

Question 5

extinct? (definition)

Answer 5

species that have died out

Question 6

Is a fossil a whole organism or fragments of an organism?

Answer 6

both

Question 7

In what rock are fossils usually found?

Answer 7

sedimentary - if sand builds up quickly, it can bury an organism/fragment.

Question 8

Fossils are usually formed from hard structures such as teeth, bones…but how can soft tissue be preserved?

Answer 8

If the organism is buried quickly

Question 9

What 4 things do fossils reveal about ancient life?

Answer 9

1. its structural make-up. 2. the sequencing of groups ver time, 3. how organisms evolved, 4. ecology of the life around these organisms

Question 10

Give an example of how a fossils reveals information about ecology?

Answer 10

fossilized plants can indicate desserts, lakes and forests at the time in that location.

Question 11

Give an example of how a fossil can suggest an organism’s structural make-up?

Answer 11

fossilized footprints can indicate how the organism walked/ crawled.

Question 12

What is relative dating?

Answer 12

judging the age of a fossil based on its location in the ground

Question 13

How are index fossils used for dating?

Answer 13

these fossils are uniquely found in only certain time periods, and can be used to determine the age of the ground layer

Question 14

What are 2 important qualifications a fossil must have in order to be considered an index fossil?

Answer 14

1. be easy to recognize, 2. occur in only a few rock layers (unique to a small time period)

Question 15

give 1 example of an index fossil

Answer 15

trilobites

Question 16

what is radiometric dating?

Answer 16

it provides information on the fossil’s absolute age by measuring the decay of isotopes within the fossil.

Question 17

half-life (definition)?

Answer 17

time required for half the radioactive atoms to decay

Question 18

Different radioactive isotopes decay at different rates. Name 1 element with a long half-life and 1 with a short half-life.

Answer 18

long- potassium. short - carbon 14

Question 19

when would you want to measure elements with long half lives?

Answer 19

for older fossils (such as rocks) and useful for figuring out whole time periods

Question 20

where does carbon 14 come from?

Answer 20

its in the atmosphere…plants absorb it….organisms eat it….and it begins to decay when the organism dies

Question 21

How was the geological timetable established?

Answer 21

using both relative and absolute dating to determine rock layer boundaries. These boundaries established the eons and periods.

Question 22

Name the 4 major geological divisions (eons).

Answer 22

1. Hadean, 2. Archean, 3. Proterozoic, 4. Phanerozoic

Question 23

In which eon did the stable continents form?

Answer 23

3rd eon, Proterozoic

Question 24

Which is the first eon?

Answer 24

Hadean

Question 25

Which is our present eon?

Answer 25

Phanerozoic

Question 26

In which eon did life first appear?

Answer 26

2nd eon, Archean

Question 27

In which eon did eukaryotic cells form

Answer 27

Proterozoic (3rd eon)

Question 28

How many eras are in the Phanerozoic eon

Answer 28

3 eras (Palaeozoic, Mesozoic, Cenozoic - current)

Question 29

Eons are divided into…?

Answer 29

eras

Question 30

Eras are subdivided into…?

Answer 30

periods

Question 31

What is the range of years a PERIOD can be (in millions)?

Answer 31

between 2 million and 100 million

Question 32

What period and era do we live in now?

Answer 32

Cenozoic era and the Quaternary period

Question 33

How many of the 4 eons are in the Precambrian time?

Answer 33

the first 3 (Hadean, Archean and Proterozoic)

Question 34

What percent of time does the Precambrian take up of earth’s existence?

Answer 34

90% of earth’s life has been spent in Precambrian time. Another 5% was in Paleozoic, 4 % spent in Mesozoic, 1% in Cenozoic.

Question 35

What are 4 of earth’s changes that have shaped history?

Answer 35

1. climate change, 2. plate tectonics, 3. volcanos, 4. meteors (mass extinction)

Question 36

What are some of the effects on life due to climate change, plate tectonics, volcanos and meteors?

Answer 36

1. natural selection, 2. new organisms created even more changes (ex. they increased the amount of oxygen and nitrogen in the atmosphere) An increase in oxygen led to decrease in carbon dioxide which allowed temperatures to go down and change the climate and ocean chemistry dramatically.