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What does this mean?

Cambrian explosion refers to the tremendous increase in the number and type of multicellular organisms at the start of the Cambrian period of the Paleozoicera. Ancestral forms of all organisms emerged then, which have gradually changed to become the life forms we see today.

Cambrian explosion: explanation http://www.fossilmuseum.net/Paleobiology/CambrianExplosion.htm

Significant changes have taken place in all groups of plants and animals.

Plants:

From being purely aquatic, plants gradually colonized land and had to cope with life in a completely different medium. They had to develop several structuralchanges, such as:

  • They developed true roots, stems and leaves with different tissues in these organs. Some plants developed flowers and fruit.
  • They developed supporting tissue like xylem and thick secondary walls with lignin.
  • They developed a means of protecting themselves against dehydration, such as the development of a cuticle and sunken stomata.
  • They became less dependent on water for fertilization, using wind and or animals to transfer pollen grains with sperm nuclei.

Animals:

Animals also became more complex than their primitive ancestors. Some colonized land and had to make further changes.

  • They developed a head with a brain and limbs on both sides of the body.
  • The digestive system became more complex, developing a gut with two openings and various glands associated with digestion.
  • They had to protect themselves against dehydration, so many developed internal breathing systems, protecting the delicate lungs.
  • Birds and mammals became endothermic, i.e. able to keep their body temperatures constant despite changes in environmental temperature.

See: http:www.khanacademy.org/video/introducti-to-evolution-and-natural- election?playlist=Biology

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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why and for what was five kingdom of classification of organisms introduced
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SUBHIKSHA
Comment on the ozone depletion over the period of 1982 to 1996
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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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