UK GCSE level age ~14-16, ~US grades 9-10 Biology revision notes re-edit 10/05/2023 [SEARCH]

 Evolution: 12. What is the origin of life on Earth?

Doc Brown's Biology exam study revision notes


There are various sections to work through,

after 1 they can be read and studied in any order.

INDEX of biology notes on all aspects of EVOLUTION


(12) How did life begin?

How did living organisms evolve on Earth from simple molecules and ions?

To me, personally, this is the greatest of scientific mysteries yet to be solved.

Despite all the fossil and genetic evidence of evolution, there is no clear answer as to how it all began!

Current evidence suggests that life on Earth began about 3.7 billion years ago (3.7x 108 years).

There are various hypotheses to suggest how some simple form of self-replicating life evolved, but that is what they are - just hypotheses!

Did life evolve in some kind of pool of simple/complex organic molecules and mineral salts?

Did the molecules of life arrive on a comet?

Did the water, the medium in which life is considered tom have evolved, arrive in massive icy comets?

Could life have evolved by hot volcanic springs under the sea?

The first problem is lack of evidence of the structure and function of early forms of life.

There are two principal reasons for this.

(i) The earliest fossil records are not clear, especially as early forms of life would have tiny soft bodies that would readily decay leaving little if any trace of the organism's existence.

(ii) Many fossils formed millions of years ago have been destroyed by the Earth's geological activity e.g. tectonic plate movements crushing and disrupting layers of sedimentary rock, volcanic activity, and the weathering and erosion of the earliest rocks - the latter means that much of the earliest layers of sedimentary rock containing many of the earliest fossils has disappeared.

I've written a wider discussion from more of a pure chemistry point of view on my webpage

Evolution and the Earth's atmosphere



INDEX of biology notes on all aspects of EVOLUTION

Big website and use [SEARCH BOX] below, maybe quicker than the indexes


HOME PAGE of Doc Brown's Science website Links to all indexes

UK KS3 Science Quizzes for KS3 science students aged ~11-14, ~US grades 6, 7 and 8

BiologyChemistryPhysics UK GCSE/IGCSE students age ~14-16, ~US grades 9-10

Advanced Level Chemistry for pre-university ~16-18 ~US grades 11-12, K12 Honors

Find your GCSE/IGCSE science course for more help links to all science revision notes

email doc brown - comments - query?

Use your mobile phone or ipad etc. in 'landscape' mode?

 Doc Brown's Biology exam study revision notes