Outline a method for dating fossils using 14c 13 year old online dating
A pentadactyl limb describes the same skeletal elements that make up the forelimbs of humans, cats, whales, bats and all other mammals.
They have evolved for different functions but the relationships between the bones in the limb are all remarkably similar.
Information like this can help to group organisms in trees of descent and suggest how long ago they had a common gene pool.
First, check a specific protein and know that mutations occur at a certain rate.
For example, the haemoglobin of gorillas only differs by one amino acid from human haemoglobin whereas elephant haemoglobin differs from human haemoglobin by 26 amino acids.
Therefore elephants separated as a species from a common ancestor with humans longer ago then did gorillas.
So, often layers of volcanic rocks above and below the layers containing fossils can be dated to provide a date range for the fossil containing rocks.For example, the forelimbs of mammals have been modified to fit their function.However similarities in these structures demonstrate that they all originate from a common ancestor.Since the rock formation contains both types of fossils the ago of the rock formation must be in the overlapping date range of to million years.Studying the layers of rock or strata can also be useful. If a layer of rock containing the fossil is higher up in the sequence that another layer, you know that layer must be younger in age.
The atoms in some chemical elements have different forms, called isotopes.