Can you explain the theory of evolution by natural selection as presented by Darwin?

Investigate and explain 2 alternatives to Darwin’s Theory of Evolution.?

• Investigate and explain 2 alternatives to Darwin’s Theory of Evolution. please explain with detail

• Answer:

  I would choose Lamarckism and Intelligent Design. These provide an excellent illustration between a scientific theory (Lamarckism) that is disproved, and something that doesn't even rise to the status of "hypothesis", much less theory (Intelligent Design). First, it's important to understand what "theory" means. When we say the "theory of X", this does NOT mean "the question of whether X occurs", it means "the explanation for WHY X occurs." This is very, very, very important! If you ever hear somebody say that X is "just a theory", you know that this person has NO CLUE what the word 'theory' means in science. Second it's important to understand that a theory not only needs to be an *explanation* for something, it needs to be a *testable* explanation. You need to be able to describe pass/fail tests ... statements of the form "if we ever see observation Y, then my theory is FALSE." Third, it's important to understand what "theory of evolution" means. It is NOT "the question of WHETHER evolution occurs." It is the explanation for WHY evolution occurs. So all three of these ... Darwinian natural selection, Lamarckism, and Intelligent Design ... are *three* proposed "theories of evolution." My point is that Darwinism and Lamarckism qualify as 'theories' (because they are testable *explanations* of WHY evolution occurs), but Intelligent Design does *not* qualify as a theory (because it is not a testable explanation of anything). [Aside: Some people may be surprised to hear me say that Intelligent Design is a proposed "theory of evolution", rather than a proposed *refutation* of evolution. I am basing this on the writings and work of Michael Behe, one of the lead (and only) scientists with legitimate credentials who have written about Intelligent Design. Behe is very, very clear that he does NOT reject evolution (the slow change in species) including common origin of modern species from common ancestors over huge timespans. Behe does NOT reject evolution. He just questions whether Darwinism is enough to explain it. So I am treating Intelligent Design ... as presented by Michael Behe ... as a claim to be a "theory of evolution" ... but one that fails to qualify as a "theory" of anything.] So let's get started: Lamarckism is the idea (named after French biologist Jean-Baptiste Lamarck) that individuals of a species pass on traits *acquired during their lifetime* to offspring. The classic example is a giraffe that, through a lifetime of stretching its neck to reach higher branches, has a slightly elongated neck that it *passes on to offspring*, which continue the process, thus explaining evolution (change) of species over time. Darwin's theory came after Lamarck's and proposed a *different* mechanism ... natural selection ... which differed in that it did not require traits *acquired during the lifetime* of the individual, to be heritable. It was not a disagreement over whether evolution (slow change in a species) occurred ... it was a disagreement over what the *mechanism* of that evolution was. Lamarck's mechanism had the problem that it depended on some way that *acquired* traits could make their way into genes ... Darwin's did not. And as we began to understand the laws and mechanisms of inheritance (genetics), Darwin's theory displaced Lamarck's completely. This is an excellent example of how *evidence* is what distinguishes between two equally valid theories (explanations) for the same phenomenon (evolution). Intelligent Design is the idea that evolution is caused or determined by *choices* made by some unknown intelligent being ... a being with unknown origin, unknown mechanism, unknown energy source, unknown design goals, and above all, unknown *motive*. As such it is an excellent example of an idea so vague that it doesn't even rise to the level of "hypothesis", much less the exalted status of "theory." A hypothesis (or theory) actually has to *explain* something. That means that it describe complex phenomena in terms of simpler concepts. Darwin's theory of natural selection, is a wonderfully simple idea that explains a *lot* of phenomena. Intelligent Design is the opposite ... it *by definition* posits a being more complex (and mysterious) than any phenomenon it claims to explain! In fact, when you ask people for evidence of Intelligent Design, watch carefully as they always, always, always respond with evidence *against* Darwinism. For example, the concept people like Michael Behe call 'irreducible complexity' ... which is a claim that Darwinian natural selection cannot explain X because X cannot be broken down into "parts" that could have evolved incrementally. These arguments have all turned out to be false (for all proposed examples of 'irreducible complexity', the Darwinists have been able to show a perfectly valid path by which that example could have evolved by incremental steps). But that's not my point. My point is that if you answer any question about evidence for your theory (ID), by responding with arguments *against* another theory (Darwinism), then this just shows that you *don't have a viable theory* that *explains* anything! Which brings us to *testability*. Lamarckism was testable (and failed the test) because it claimed that we should see evidence of *acquired* traits passed on to offspring. Darwinian natural selection is testable (and has passed many tests) because it predicts that by changing the selective pressures on a population, can change the developing traits. But Intelligent Design makes no predictions, and therefore is not "testable". There is no statement than an Intelligent Design advocate will accept that says "if we see observation Y, then Intelligent Design is false." So I think it would be a great exercise to research and explore the two ideas of Lamarckism and Intelligent Design. This is a good way to understand what "theory" means ... what "theory of evolution" means ... and what "testable" means. And it is a good way to understand why pretty much ALL biologists in the world today, see Darwinian natural selection as the primary explanation for WHY evolution occurs.