Unit 4 10B: Fossils

Question 1

Fossil

Answer 1

The remains or traces of a preexisting life form

Question 2

Fossil record

Answer 2

A record of organisms that once lived through geological time, documented by fossils

Question 3

Palaeontologist

Answer 3

a scientist who studies fossils

Question 4

Trace Fossil

Answer 4

Fossilised signs or remains of an organism’s activity, e.g. tracks

Question 5

Petrification

Answer 5

The replacement of an organism’s organic matter with minerals

Question 6

Mould fossil

Answer 6

An impression that forms from the decay of the organism within a rock

Question 7

Cast fossil

Answer 7

Fossil formed when an organism decays, leaving an impression, which fills with minerals, resulting in a 3D object of the organism’s external surface

Question 8

Sedimentary rock

Answer 8

A type of rock that is formed from the accumulation of sediment into layers

Question 9

Metamorphic rock

Answer 9

A type of rock that arises from the transformation of existing rocks

Question 10

Sediment

weathering and erosion

Answer 10

Naturally occurring material that is formed through the effects of weathering and erosion

Question 11

Transitional fossil

Answer 11

A hybrid fossil that shows traits of both an ancestral group and a descendant group, allowing the comparison of structures to determine relatedness

Question 12

Absolute dating

Answer 12

Determines the actual age of a specimen being analysed

Question 13

Relative dating

Answer 13

Determines the age of a specimen by comparing its placement with that of other fossils or the rock layers it is found in

Question 14

Stratigraphy

Answer 14

A branch of geology that uses th principle of rock succession to examine the order and position of strata in connection with fossilised remains

Question 15

Index fossil

Answer 15

A fossil of organisms that were widespread but only existed for a short period of time, that is used to date and correlate that strata within which it is found

Question 16

Radiometric dating

Answer 16

A method of absolute dating that uses the concept of the decay of an isotope into its stable daughter isotope at a known rate to determine the age of a geological sample

Question 17

Isotope

Answer 17

Variant of an element that differes in the number of neutrons in the nucleus

Question 18

Half-life

Answer 18

The time taken for 50% of an unstable parent isotope to decay into its corresponding stable daughter isotope

Question 19

What is the half life of Carbon 14

Answer 19

5730 years

Question 20

Faunal Succession

Answer 20

Is a techinque used to determine the relative age of fossils, through the basis that the deeper the rock strata the older the corresponding fossils

Question 21

Fossilisation process

Answer 21

1)Organism dies and body is rapidly buried in sediment
2)Soft tissue decomposes
3)Compression increases as layers of sediment form above the organism
4)Original hard structures become porous, minerals from the surrounding sediment seep in and replace to form the fossil.
5)Sediment i hardened into rock from pressure
6)Rock may become eroded, exposing the fossil.