fossils and geo time scale

Question 1

What is a fossil?

Answer 1

A fossil is the natural remains or evidence of living things from prehistoric times typically over 10000 years old to be classified as a fossil

Question 2

Who studied fossils?

Answer 2

Palaeontologists do, to learn more about and understand earth’s past

Question 3

What do fossils show us?

Answer 3

Fossils reveal how organisms have changed over time, providing evidence of species and evolutions and indicate environment and climate changes in history.

Question 4

How are fossils formed?

Answer 4

Fossils are formed when dead plants or animals are buried under layers of sand and mud. Over time, pressure turns these layers into sedimentary rock, and minerals replace the organic matter creating a stone replica

Question 5

What happens to fossils over time?

Answer 5

They can be eroded out of the rock, but most remains are lost during this process.

Question 6

What is uplift in geology?

Answer 6

Upmost is the process where underground rocks rise to earth’s surface - fossils become more accessible

Question 7

What is mineralisation?

Answer 7

When an organism dies and is buried under sand and sediments. Over time, minerals replace the original material, leaving only minerals behind.

Question 8

What is carbonisation?

Answer 8

Happens when a dead organism is compressed over time, causing gases to escape and leave a carbon outline of the organisms remains

Question 9

What are miles and casts?

Answer 9

An impression left by a hard part of an organism (like a deep imprint) A case is when the mild fills with sediment or minerals, creating a 3D replica

Question 10

What are trace fossils?

Answer 10

Provide evidence of an organisms activity or behaviour such as footprints or bite marks.

Question 11

What are preserved remains?

Answer 11

Organisms that have been found intact in a suitable environment for thousands of years, such as those in amber or ice

Question 12

How can geological history be interpreted from sedimentary rocks

Answer 12

Using the law of superposition, states that in undisturbed layers older fossils are in bottom layers and vice versa. Disturbances like earthquakes volcanic activity and human activity can disrupt layers and provide insight into geological events

Question 13

What are index fossils?

Answer 13

Index fossils are the remains of organisms that lived during a specific geological age, used to identify and date the age of strata in different locations

Question 14

Two main rules of relative dating?

Answer 14

Law of superposition : In undisturbed layers, older rocks are at the bottom and younger rocks are at the top.
Law of faunal succession : fossil species are in a specific recognisable order in the same layer

Question 15

What classifies and index fossils?

Answer 15

Distinctive, globally widespread and abundant

Question 16

What are strata?

Answer 16

Layers of sedimentary rock that have distinct characteristics helping identify and date geological events

Question 17

What is stratigraphy?

Answer 17

Comparing rock layers in different locations

Question 18

What is a fluorine analysis?

Answer 18

Determines the relative age of bones and artefacts by measuring the amount of fluorine they can contains, which increases the longer they’re buried.

Question 19

What is absolute dating/ radioisotope dating?

Answer 19

Absolute dating determines the age of fossils by measuring the remaining radioactive isotopes they contains. An isotopes half life is how long it take for half the original isotope to decay

Question 20

How are periods measure in the geological time scale?

Answer 20

By millions (mya)

Question 21

What was the first period in the time scale?

Answer 21

Precambrian, dominance of bacteria

Question 22

What is the palaeozoic era

Answer 22

Animals with shells, 6
Period

Question 23

What is the Mesozoic era?

Answer 23

Age of reptiles, 3 periods : Jurassic, Cretaceous, Triassic

Question 24

Which era do we currently live in?

Answer 24

Cenozoic era, tertiary and quaternary

Question 25

How many major eras are there

Answer 25

Palaeozoic, Mesozoic, cenozoic

Question 26

what are the 4 types of fossils and their meaning?

Answer 26

Original : when a part of an organism is preserved, with its chemical composition being similar to when it was living
Replacement : When a part of the organism is chemically changed into another mineral
Carbon Film : When the dead part of the body decays and leaves a black deposit of carbon
Indirect : evidence of remains such as imprints, molds, casts

Question 27

What are the five types of preservation environments for fossils and the best type

Answer 27

Marine environments, cause more sediment and mud. 5 types are permafrost, tar, amber, peat and dry air

Question 28

What are the five types of preservation environments for fossils and the best type

Answer 28

Marine environments, cause more sediment and mud. 5 types are permafrost, tar, amber, peat and dry air

Question 29

Why is the fossil record incomplete

Answer 29

Because some fossils are not based in marine environments and may have eroded

Question 30

What is tree ring dating

Answer 30

Counting growth rings in wood chunks of of trees

Question 31

What are transitional fossils

Answer 31

Fossils that exhibit characteristics from both its ancestral and derived form