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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

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 to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
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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