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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 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, Principles of biology. OpenStax CNX. Aug 09, 2016 Download for free at http://legacy.cnx.org/content/col11569/1.25
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