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An introduction to evolutionary theory, summarizing some of the key lines of evidence in support of the theory.


How stupid of me not to have thought of that.
– Thomas Huxley, after reading Darwin’s Origin ( On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life ).


What is Evolution? Surely everyone has heard the word, and perhaps a lot of other words to describe it, but do you really know what that word means, in the context of biology? Here are a few common notions about evolution. How many do you agree with?

  1. Evolution has never been observed directly.
  2. Evolution is only a theory, and has not been shown to be a fact.
  3. Evolution means that life originated, and living things change, randomly.
  4. Evolution is progress; organisms get “better” and more complicated whenever evolution occurs.
  5. Evolution means that individual organisms change.
  6. In order for evolution to occur, the offspring of some organisms will have to be radically different from the parental organisms.

If you said that all of these statements are false, then you have a good understanding of evolution. They are indeed all untrue. However, this is a list of some fairly common misconceptions about evolution, and many people in the world (and particularly in the USA) share one or more of these misconceptions. It is likely that you think that some or all of these statements are true. One of the hardest parts of learning is to undo a well-established misconception, so if you do think that one (or more) of those statements is true, this chapter might be a bit harder for you. But it will be worth the effort, since, as you will learn below, evolution is the guiding framework for modern biological science. Once you have a good understanding of evolution, and the mechanisms that drive it, you will be well-poised to learn and understand the biology that comes in the rest of this course.

Evolution – what is it?

The biological world is extremely diverse. In fact, that is one of the most powerful realizations that come from the study of biology, or even just from being an observant person in the world. Living things range from the microscopic bacteria to the immense blue whale. They have a diversity of life styles and metabolic capacities, from photosynthetic creatures who can make their own food from carbon dioxide gas, to predatory creatures, all the way to parasitic creatures who have some of the most complicated life styles of all. Within any one of these groups, there is also astounding diversity. Open any field guide, whether for birds, mammals, flowering plants, or mushrooms, and you will be confronted with an abundance of colors, sizes, shapes and behaviors. Even within a single species, say Homo sapiens, there is diversity. Look around your classroom and you will see people with a wide variety of skin colors, hair colors, eye colors, heights and weights. This diversity is a fact, and for many millennia, human beings have been trying to come up with explanations for that well-observed fact.

Questions & Answers

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
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?
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
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor 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, Principles of biology. OpenStax CNX. Aug 09, 2016 Download for free at http://legacy.cnx.org/content/col11569/1.25
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