Question

how are fossils formed? describe in brief 2 methods of determining the age of fossils? ​

Answer 1

Fossils are the preserved remains or traces of animals, plants and other

organisms from the remote past. They are formed by a continuous process of

burying and decomposition over a certain period.

Fossil formation:

 Some invertebrates living on the sea bed died and were buried in the

sand.

 More sand was accumulated and formed sandstone under pressure.

 After millions of years, dinosaurs living in the area died and their

bodies were buried in the mud.

 The mud got compressed into the rock, just above the rock containing

earlier invertebrate fossils.

 Again millions of years later, the bodies of horse-like creatures dying

in the area were fossilised in the rocks above the earlier rocks.

 Much later, because of erosion and water flow, some rocks wore out

and exposed the horse-like fossils.

Two methods to determine the age of fossils:

 When dug into the Earth, the fossils closer to the surface are more

recent as compared to the fossils found in deeper layers.

 The fossils can also be dated by detecting the ratios of different

isotopes of the same element in the fossil material. This process is

known as radiocarbon dating. When living organisms change into

fossils, their rate of radioactive C14 decay decreases slowly. In this

way, the age of fossils can be determined with the help of radioactive

C14.

Answer 2

Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.

Describe in brief, two methods of determining the age of fossils.List any two roles of fossils in tracing evolutionary relationships. burying and decomposition over a certain period. Fossil formation: ... The mud got compressed into the rock, just above the rock containing earlier invertebrate fossils.

The age of the fossils is determined by Radiometric or Radioactive dating technique in which the half life of carbon and found radioactive elements is determined to calculate the age of fossil or the rock.