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The history of life on Earth is described in various publications and web sites ( e.g. , Speer, B.R. and A.G. Collins. 2000 ; Tudge, 2000 ; Lecointre and Guyader, 2001 ; Maddison, 2001 Eldredge, 2002 ); it is also discussed in the module on Macroevolution: essentials of systematics andtaxonomy. For the current purpose of understanding what is biodiversity, it is only necessary to note that that thediversity of species, ecosystems and landscapes that surround us today are the product of perhaps 3.7 billion( i.e. , 3.7 9 ) to 3.85 billion years of evolution of life on Earth ( Mojzsis et al. , 1996 ; Fedo and Whitehouse, 2002 ).

Thus, the evolutionary history of Earth has physically and biologically shaped our contemporary environment. As noted inthe section on Biogeography , plate tectonics and the evolution of continents and ocean basinshave been instrumental in directing the evolution and distribution of the Earth's biota. However, the physicalenvironment has also been extensively modified by these biota. Many existing landscapes are based on the remains ofearlier life forms. For example, some existing large rock formations are the remains of ancient reefs formed 360 to 440million years ago by communities of algae and invertebrates ( Veron, 2000 ). Very old communities of subterranean bacteria may have been responsible for shaping manygeological processes during the history of the Earth, such as the conversion of minerals from one form to another, and theerosion of rocks ( Fredrickson and Onstott, 1996 ). The evolution of photosynthetic bacteria, sometime between 3.5 and 2.75 million years ago Schopf, 1993 ; Brasier et al. , 2002 ; Hayes, 2002 ), played an important role in the evolution of the Earth's atmosphere. Thesebacteria released oxygen into the atmosphere, changing it's composition from the former composition of mainly carbondioxide, with other gases such as nitrogen, carbon monoxide, methane, hydrogen and sulphur gases present in smallerquantities. It probably took over 2 billion years for the oxygen concentration to reach the level it is today ( Hayes, 2002 ), but the process of oxygenation of the atmosphere led to important evolutionary changes inorganisms so that they could utilize oxygen for metabolism. The rise of animal and plant life on land was associated with thedevelopment of an oxygen rich atmosphere.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, What is biodiversity. OpenStax CNX. Feb 05, 2009 Download for free at http://cnx.org/content/col10639/1.1
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