Arete

OK, So I'm a research scientist in an experimental evolution lab. We generally use RNA viruses as our model organisms, due to their high mutation rates and short generation times. Irradiating seeds in the hope of producing advantageous mutations is a relatively widely used method to produce crop varieties http://en.wikipedia.org/wiki/Irradiation#AgricultureHowever I can see a number of potential flaws in your proposal. 1) Anything which produces enough radiation to mutate seeds is a carcinogen and needs to be handled using the appropriate safety protocols. The last thing you'd want to do is end up like the nuclear boy scout. Furthermore, if you're intending to do the experiment in the same room you sleep in, I'd be strongly advising against using radiation to induce mutation. 2) If you want to observe actual adaptive evolution in weeks - months, plants will probably take too long. I'd use a microbe. Of course, certain microbes are also dangerous, but some are relatively safe to work with - I'd pick a BSL1 organism - E. coli stands out as one of the most accessible. (Btw there's TONNES of cool stuff on the Carolina.com website - DNA extraction kits, bacterial ID kits, enzymatic shearing kits, epidemic simulation kits, etc, etc etc - you could do a crapload of cool stuff for way less than $500 - they even have an experimental evolution kit to examine anitbiotic resistance http://www.carolina.com/inquiry-science-evolution/inquiries-in-science-changing-over-time-kit/FAM_251014.pr?catId=10631&mCat=10476&sCat=10629&ssCat=&question=) edit to add another sweet looking evolution experiment kit - drospohila (fruit fly) red eye mutation kit http://www.carolina.com/drosophila-fruit-fly-genetics/natural-selection-with-drosophila-kit/FAM_171995.pr?catId=10404&mCat=10337&sCat=&ssCat=&question=) 3) Given you probably don't have access to any sequencing technology, I'd focus on differential treatments (e.g., culturing media, temperature, humidity, etc). and growth compared to the ancestor strain (which you kept in the freezer) on the different treatments. 4) If you're going to go through with it, please try and find somewhere other than your room to do it. Even though E. coli don't typically infect healthy people, it'd be much better to be doing this in a garage/shed/etc. Have fun. Edit to add - depending on where you live both myself, and other scientists I know take on high school students as interns during the summer. If you're either near Connecticut or the Central Valley in Cali, drop me a PM and I might be able to connect you to a lab where you could either do or help with an evolution experiment.

It would be helpful to your understanding if you read up on the evolutionary species concept. To go back to previously cited links, dogs, are resultant from multiple domestication events and a long history of gene flow with both each other and wild canine species. Therefore they do not have independent evolutionary histories. Ergo, under the evolutionary species concept, they could not be considered species. I think you need to revisit the definition of phenotypic plasticity. If different morphotypes are distinct lineages, the phenotypic differences are not due to plasticity. Also, dog breeds are, at best partially genetically isolated at a prezygotic level. To try and claim that there is a postzygotic reproductive incompatibility would be false. The example holds - you cannot make the blanket assertion that dogs are more phenotypically plastic than all naturally occurring species - which is what you claimed, after all. 1) Morphology can be empirical, however you use of it in previous posts is decidedly not so. If you make a clear statement like "dogs vary in body size/color/etc more than any other species" it can be quantified. By making a vague arm waving generalization about phenotypic variation without specifics leaves the judgement you make on other species entirely subjective, and thus rather worthless. 2) See previous examples, here's another in Mimulus 3) Again, you need to revisit phenotypic plasticity, as if each phenotype is a distinct lineage, the variation observed can no longer be termed to be plastic. Plasticity refers to the variety of morphotypes which arise from the same genotype, exposed to different environmental pressures. The dendrobatid frog populations shown in the previous photo are allopatrically distributed on islands. It's been clearly explained previously and linked to. See above. Additionally, the presence or absence of reproductive isolation is not the be all and end all of species definitions. For e.g. about 25% of plant species can hybridize and to go back to canine species, coyotes and wolves can hybridize, but remain undisputed, distinct species. Ultimately, what I think you're missing with the dog example is that the phenotypic distinction between breeds is at best, a precursor to speciation. Assuming the breeds are viable sub-populations within Canis lupus domesticus (which is debatable due to low effective population sizes and the need for human intervention) the separation between them and other dog breeds needs to persist long enough for them to develop characteristics which allow for unequivocal designation as an evolutionarily distinct metapopulation. At the time being, they haven't acquired enough of these traits - particularly at the genetic level to warrant most biologists in recognizing them as such.

The time it takes for speciation to occur is a function of generation time and population size. Following isolation, it takes approximately 4 x the effective population size generations to approach a new genetic equilibrium in a given population http://www.jstor.org/stable/2460440?seq=10#page_scan_tab_contentsprovided that population isn't exceptionally small and thus subject to founder effects. So using a humans as an example, population with an effective size of 1000 would take 4000 generations (~80,000 years) to be genetically distinct from the population it split from. Obviously, factors like migration, population growth, etc will affect this very rough estimate.

It's because creationism - both YEC and Intelligunt design do not adhere to the scientific method, and are therefore not science, and yet we have a lobbyist movement demanding that they be treated as science, both in terms of legislature and education. Imagine you run a banana stand. Some guy comes up with a trout and demands you sell his "banana" alongside the others in your stand. You're like "WTF dude no, that's a trout. It's not yellow, curved, or even a fruit. You need to go to the fish market and sell it there, this is a fruit market." Then trout guy lobbies the market, trying to get the definition of fruit changed so that fish are included, and trout are reclassified as a banana, so he can sell trout as bananas in the fruit market. Some less educated fruit buyers start buying the trout and feeding it to their kids on cereal for breakfast. Obviously, raw trout is bad for you and can make you sick, but now you have a generation of people who think it's a fruit and eating it on your cereal is perfectly ok and normal. Switch back to creation and science. People are actively teaching their kids, and agitating for more kids to be taught that a bible story claiming that the earth is 6,000 years old is equal to all of our cumulative understanding of biology, geology, chemistry and physics. They will happily dismiss any statement science makes, no matter how well supported, that contradicts their particular version of a bible story, because, well, they've been taught that it is totally fine to do so. So you end up with a community of people who don't actually believe in the scientific facts which allow their computers or medicine to work, and instead prefer to believe it was a "miracle" or effectively magic. Now, someone like perhaps myself, who has spent years working on a potentially life saving medication for a disease, potentially finds the idea that someone whose life is saved by said medication will dismiss my efforts and instead invoke magic, is a little offensive and very dismaying. Such a scenario understandably invokes a strong resistant response in the scientific community to creationists.

On an evolutionary timescale, they very very recently have engaged in gene flow with wolves and other canine species, as is evident from the article. The point is that using the evolutionary species concept, as described earlier, we can easily determine that dog breeds do not represent discrete metapopulations with independent evolutionary histories. As such its unequivocal that they don't represent species. The statement you made was that no naturally occurring species has as much phenotypic plasticity as domestic dogs. Social insects, rather succinctly disprove that notion. Furthermore, a queen and a worker are actually genetically identical, and not all memers of "sterile" castes are sterile (e.g. around 1 in 10,000 worker bees are fertile http://www.jstor.org/discover/10.2307/2830426?uid=3739256&uid=2&uid=4&sid=21105246696821) These are subjective judgments of phenotypic variation, and thus worth little - I have no idea you can tell the frogs have the same body size from that photo, for e.g. as it's actually wrong - they vary in body size, toxicity and mating call http://onlinelibrary.wiley.com/doi/10.1046/j.1439-0310.2003.00863.x/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2007.03479.x/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false http://link.springer.com/article/10.1007/s10886-006-9034-y#page-1. The point is, that many naturally occurring populations display a wide variety of phenotypic variation within populations across an extremely wide variety of parameters. You can't single domestic dogs out and make a sweeping comment about their phenotypic variation. This is again, incorrect. See cryptic species and hybridization. The standard definition of a species under the evolutionary species concept, as previously stated, is a meta-population with an independent evolutionary history. Monophyly, reproductive isolation, phenotypic distinction, etc are all indicators of that evolutionary history, but not definitive of it. See previously cited Dq Quieroz paper.

Not to mention that the domestic dog is the result of numerous independent domestication events, followed by long term and frequent gene flow with a variety of wild canine species. http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004016#pgen-1004016-g004 Now, the most widely applied species concept in current science is the evolutionary species concept http://statgen.dps.unipi.it/courses_file/GdP/Papers/DeQueiroz_SpeciesConceptDelimitation_Syst.Biol.2007.pdf. To paraphrase, this concept defines species as meta-populations which share a common and distinct evolutionary trajectory. Due to the complex nature of Canis lupus domesticus multiple origins, widespread gene flow with other species, dog breeds do not meet the criteria of the evolutionary species concept -moerover represent phenotypic outliers within a population, and generally would be rightly not considered to represent species. As far as examples in nature, try social insects. Eclectus parrots Poison dart frogs (Dendrobates pumilio) etc. Phenotypic variation is not synonymous with species diversity anywhere in nature. Dogs are not an exception.

Then you may want to reconsider trying to communicate anything resembling a scientific concept. If posting on forums causes you to behave as such, I' hate to think what peer review would do to your blood pressure.

A) No one understanding your points is in no way an indicator that you are smarter than everyone else - all it means is you are bad at explaining it, or wrong. The smartest people I know are great at making complex concepts seem simple - these are the people I academically aspire to be like. People who take simple concepts and attempt to make them impenetrable (there are a lot of them, both here and in formal academia) are often less intelligent than they think they are. B) I've never once seen a person on this forum claim to be correct and completely misunderstood (.i.e., everyone here is an idiot and i alone understand this concept) and not be comprehensively and trivially proven to be completely wrong. If people are pointing out incomprehensible statements or flaws in your idea, claiming persecution/superior intellect operates like a litmus test for crackpottery. In fact this thread in of itself operates as a giant red flag that you're very well impervious to rational thought. In light of these facts, it might be advisable to adjust your posting style - it will probably yield better discussion that will assist your understanding and scientific communication skills. Being patient and better explaining yourself is crucial to being an effective scientist - I personally work in evolutionary medicine, and careful, concise, clear explanations of principles are critical in explaining science to both clinicians and patients. If I can make a high school educated parent know how vaccinations work, and convince them to vaccinate their kids, I'm a better scientist than someone who gives up in disgust because they can't explain herd immunity without using inpenetratable jargon

So you can't support anything you're postulating, then. In that case, you can't say things like "contrary to evidence/observation" because what you mean is "contrary to my anecdotal experience/own opinion". Nope, you can directly observe human evolution... http://www.pnas.org/content/107/suppl_1/1787.abstract Just echoing swansont here, but you appear to be simply making it up as you go, rather than applying any sort of science.

No, this would be middle school level biology. I'm a little flabbergasted that you're finding it so hard to accept such a basic, simple concept in biology. I would really suggest doing a little reading, as you seem to have a lot of incorrect ideas about biology in general. I think it would be of great benefit to your understanding to do some basic research . At the moment it does seem like you're not even reading the provided links in previous posts, given the repletion of incorrect assertions, which makes it difficult for any progression of the discussion. "Environmental factors prevailing during early life that have been linked to long-term changes in lung structure, lung function and respiratory health include undernutrition, preterm birth, reduced intrathoracic space, respiratory infections, maternal tobacco smoking and exposure to allergens." https://www.karger.com/ProdukteDB/Katalogteile/isbn3_8055/_91/_39/Early-life_03.pdf Here is a list of known developmental teratogens http://www.purdue.edu/ehps/rem/ih/terat.htm. A myriad of environmental exposures can influence fetal development. Could you please provide a citation for these statements... many of them are inherently flawed or outright incorrect. This might be so when, as you have done, choose to define fitness as something different from the definition of the term in science. But then I could choose to define a potato as a airplane and tell everyone else that they are wrong about french fries. It wouldn't make very much sense though. I think most of what you are displaying is a fundamental lack of understanding about fundamental biology. I again would strongly suggest catching up on some basics, as the current discussion is rather fruitless.

That's the ENTIRE POINT of gene-environment interaction. It's not a dichotomy at all. The physical characteristics of an organism are a result of a COMBINATION of the ENVIRONMENT and GENES. I'm not sure it can be put more simply.

I really don't understand how any of these questions relate to the concept of genotype-environment interactions. The phenotype = genotype x environment concept is one of the oldest ideas in genetics (often characterized as nature vs nurture). It is simply that the physical characteristics of an organism is a result of both its heritable components, and the environmental conditions it is exposed to. This is an extremely fundamental idea in biology, which is generally taught in early high school and is supported by an inordinately gigantic body of observation evidence spanning centuries. When you say you don't agree with it, it becomes difficult to have any sort of meaningful discourse about the topic, as is demonstrated by your non sequitur response.

So I think the discussion is at a fatal impasse. Trying to discuss evolution with someone who denies the existence of genotype-environment interactions is rather like trying to discuss gravity with someone who disagrees that objects are attracted to the earth.

Ok, I'm going to have to bow out in order to stop procrastinating and get on with an NSF pre-proposal, but I'd like to point out a few more inaccuracies in what you're saying, in the hope of providing better understanding: This is untrue: The phenotype (i.e. structure and behavior) of an organism is a product of genotype AND environment. Two identical genotypes, exposed to different environments can result in different phenotypes e.g. http://www.nature.com/hdy/journal/vaop/ncurrent/full/hdy201492a.html This is untrue. Human genomes are largely identical across populations http://www.nature.com/scitable/topicpage/using-snp-data-to-examine-human-phenotypic-706. When you look at gene expression (which should be highly driven by the environment), 25% of expression differences are between populations rather than individuals within populations. http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1004549 The second statement is entering not even wrong territory. Fitness is important in any population undergoing selection. This pair of statements appear to be contradictory. Fitness isn't relevant, but the environment selects for particular genes and expression profiles? If the environment is selecting specific genes/alleles, the fitness of those genetic elements is inherently important. I really think you should pick up an introductory evolution or population genetics book. I think it would clear up a lot of the misunderstandings you're having, and you'd find it extremely interesting. If you want some recommendations, feel free to PM me. The model you're talking about is called punctuated equilibrium. It's not a new idea, it's actually been around for 40 years or so. You're correct in that it wouldn't make sense if populations experienced no environmental fluctuation, and never migrated. However in light of what we know about how the environment has changed in the past, and how organisms have moved around the planet, punctuated equilibrium is perfectly consistent with evolutionary theory. In addition, Giraffes didn't "suddenly appear". The Giraffidae fossil record is actually pretty good, and shows that evolution of the modern giraffe appears to have occurred over an 8 million year period, and giraffe like animals have been around for about 25 million years http://www.tandfonline.com/doi/abs/10.1080/00359190309519935#.VLP0CyvF98Mand was likely to be influenced strongly by sexual selection http://bill.srnr.arizona.edu/classes/182/Giraffe/WinningByANeck.pdf as well as browsing. No 'Goddidit' needed. Ok, so in your housefly "experiment" I doubt you would observe much actual evolution. A single housefly generation is typically 2-4 weeks, so you'd have to conduct an experiment for an inordinately long time to observe a quantifiable genetic change. For comparison, our lab works on viruses which infect bacteria. We can typically expect ~6-12 generations per day, dependent on the particular virus. Our experiments typically run for 2-6 weeks to observe quantifiable changes. Similar drosophila experiments (generation time is about a week) run for months, so a proper housefly experiment would have to run for a year or more to base any conclusion on. Even so, by killing flies, you applied selection pressure, then when you removed the selection pressure, the flies reverted back to the "pre selection" phenotype. That's perfectly consistent with mainstream evolutionary theory. Given we have actual data, we can generate hypotheses based on educated guesses, but you're right, it could very well have been a selection pressure we haven't considered that caused giraffes to evolve the way they did. This is confusing - you're concluding by saying you accept that natural selection acting on variation in a population does result in diversification?

Your "point" seems to be based on a common, gross misinterpretation of what fitness means in the context of evolutionary biology, and a subsequent series of false assumptions regarding observations surrounding fitness. In the context of evolution, fitness is the quotient of genetic material an individual in a population passes on to the subsequent generation. Whether that individual increases its fitness by avoiding predation, surviving a disease, or whatever else you're proposing as a mechanism for increased fitness is incidental. Fitness, in an evolutionary sense is the actual rate of fecundity - nothing more, nothing less. The role of differential fitness (i.e. selection) in evolution is comprehensively documented via observation on many scales. Resultantly, the claim that differences in fitness driving evolution is "contradictory to observation" is comprehensively wrong and trivially refuted by observation (see previous links to observational data) . I don't really understand how you can continue to make that argument and if you intend to do so, I'd really like to see the contradictory observations you keep alluding to, rather than continued speculation.

This is categorically untrue, as I stated in the other thread you claimed it. We can define populations using basic Hardy Weinberg principles. It seems like your objections are based on a faulty understanding of evolutionary theory, and falsely assumed "observations" which contradict what is a actually observed in nature.

Sorry, but there's plenty of evidence (this paper is a particularly good review of examples of ecological speciation http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2007.01240.x/fullbut for more evidence, see below) including direct observation. This statement is simply wrong - there's no other way to put it really. http://www.sciencemag.org/content/323/5915/737 http://www.nature.com/nature/journal/v429/n6989/abs/nature02556.html http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2004.00715.x/full http://www.sciencedirect.com/science/article/pii/S0169534709001268 Precisely which observations are you referring to?

The theory of evolution does not make any predictions or statements regarding the origin of the universe, or even biological life - so I'm not sure how this question fits with the thread topic.

This statement is inherently incorrect, but I fear indicates a fundamental lack of knowldege regarding basic biology. I'm very sorry if this is what you are being told as part of your schooling, as it's simply a lie, and that isn't fair to you. I think a few basic defintions are needed: 1. Biological evolution: At its most basic sense, evolution is the change in allele frequency, in a population, over time. This phenomenon has been directly observed countless times, in virtually (likely every, but I'll avoid absolute claims) population that has ever been looked at. Through scientific investigation we understand, to a large extent, that mutations in the DNA/RNA genome of organisms are heritable, and largely responsible for the physical changes observed in populations over time (i.e. mutation causes observed changes in allele frequency) . We also know that particular environmental conditions and circumstances favor the propagation of particular genotypes (i.e. selection influences observed changes in allele frequency). Prima facie biological evolution is an observable fact. 2. The theory of evolution: The theory of evolution postulates that all of the organismal diversity of Earth occurs due to biological evolution. While this obviously cannot be directly observed due to the time scale involved, like many other scientific theories which occur over long time scales (e.g. plate tectonics, the formation of fossil fuels, most of geology and astrophysics, etc.) we can make predictions about what present day organisms will be like, if organimsal diversification did arise through biological evolution. Examples of biological fields which make predictions in accordance with the theory of evolution include (but are not limited to): comparative genomics, phylogenetics, biogeography, morphology, molecular ecology, population genetics, experimental evolution, paleontology, and many others. The establishment and continual testing and refinement of the theory of evolution DOES follow the scientific method - any claim to the contrary is simply false. Additionally, any claim that the theory of evolution is based on unsupported speculation is, at best, supremely ignorant of the vast number of supporting observations which are in accordance with predictions made using the theory of evolution, and finally, if direct observation is required for a scientific theory to be somehow "valid" then vast swathes of science (geology, atomic science, astrophysics, etc) are also invalid - which doesn't make very much sense. 3. Theory: In science, a theory is a well substantiated explanation of observable phenomena. Theory is as strong as an explanation gets in science. A common misconception is that a theoy is secondary to a scientific law. This is incorrect. A Law in science is generally an observation that holds true for all replications - to demonstrate, the LAW of gravity is that if you drop something, it accelerates towards the earth at 9.8ms-1. The THEORY is that this observation is explained by attractive forces between the Earth and the dropped object.

The main issue with the argument for irreducible complexity is that it basically boils down to a logical fallacy known as argumentum ad ignorantium or the argument from ignorance. In essence, the argument is based on the fact that someone (in this case, yourself) doesn't understand or accept the mechanism by which a single celled common ancestor gave rise to multi-cellular life forms. The reason that the argument is illogical is that a lack of understanding of how a proposed mechanism functions is in no way a proof that rejects the mechanism. Therefore the argument has no logical basis and can be trivially dismissed. Furthermore, most, if not all, of the examples thrust forward as "irreducible" have been shown conclusively to be reducible. e.g. the bacterial flagellum http://www.nature.com/nrmicro/journal/v4/n10/full/nrmicro1493.html

So, basically you're saying that because intra-specific genetic variation exists, populations and species cannot. That's profoundly wrong. While biological diversification is a continuum and divisions are somewhat arbitrary, these categories exist. I'm repeating myself, but evolution is a population process - it is nonsensical to claim that populations don't exist. Nope, sorry. Again, this is repetition of earlier posts, but population genetics is supported by a wealth of observation. Theory and observation are not contradictory here. Nope, rabbits, by and large have the same genes. Individuals may different gene variants - called alleles. I belive this a gross misunderstanding of the difference between a gene and an allele, and thus you're misinterpreting what genetic variation is. There is actually eight species of rabbit. Each has a holotype and a formal description. So this is wrong. Sorry, but no. We can define populations using basic Hardy Weinberg principles. No, populations conform to genetic principles and are quantifiable entities, as linked to above. Natural selection and survival of the fittest are the same thing. I'm sorry, but your visceral knowledge is plain wrong, in many respects and I think this thread is becoming a good example of how "visceral knowledge" is inadequate to understand science. If you wish to understand what's going on with bottlenecks and genetics, I'd read up on a little basic population genetics. Some of the concepts are a little counter-intuitive at first, but I'm sure you will find it interesting.

Actually, the human genome contains approximately 20,000 coding genes. http://en.wikipedia.org/wiki/Human_genome#Coding_sequences_.28protein-coding_genes.29 As a diploid organism, each human carries a maximum of 2 copies of each orthologous gene. Allelic variation (i.e. variation in the coding sequence of the same gene) therefore occurs predominately between individuals within a population. It therefore stands to reason (and is backed up by extensive empirical observation) that reductions in population size reduce genetic variation in a population. I'm sorry but this is quite simply incorrect. Evolution is a population process - defined as change in allelic frequency over time. This is super introductory biology. As the genetics of an individual does not change over the course of its lifetime, they categorically cannot evolve, in a biological sense. Species are generally defined as meta-populations of organisms with a shared evolutionary trajectory. I'm not sure how you could think or justify saying that "Evolution simply doesn't occur to species".

This is your misunderstanding - they don't. A population which undergoes a rapid reduction in effective population size loses a considerable degree of genetic diversity. Rare alleles are more likely to be lost than common alleles. Even when the population recovers, genetic diversity is lower than a population which has remained stable over the same duration. It's been explained in the previously linked articles, but this picture explains it succinctly:

Population bottlenecks reduce effective population size, and thus genetic diversity. A reduction in genetic diversity generally results in slower rates of evolution within a population. This is really basic population genetics. http://evolution.berkeley.edu/evosite/evo101/IIID3Bottlenecks.shtml Actually the exact opposite is true. Most of the species which have depauperate genetic diversity compared to humans have recently been through a population bottleneck. E.g. cheetahs, elephant seals, american bison, etc. In fact, humans are thought to have gone through a population bottleneck around 140 -200,000 years ago. http://en.wikipedia.org/wiki/Mitochondrial_Eve Strong selective pressure reduces genetic population diversity - it does not increase it. Again this extremely fundamental population genetics. http://agron-www.agron.iastate.edu/~weeds/AG517/Content/WeedEvol/NaturalSelection/genediverse.html No, it isn't. A population bottleneck is a sharp reduction in effective population size. Therefore, by definition, rapid. Population reduction is also not an ongoing process. http://en.wikipedia.org/wiki/Population_bottleneck I have no idea why you would think that a reduction in effective population size would lead to an increase in genetic diversity. It is not the case, and I can't see any logical reason why you would expect it be so. It is almost universally observed that a population that is at risk of extinction displays low genetic diversity. http://en.wikipedia.org/wiki/Conservation_genetics I'm not talking about the fossil record, I'm talking about a well characterized relationship between effective population size and genetic diversityhttp://www.nyu.edu/pages/projects/fitch/courses/evolution/html/genetic_drift.html. Effective population size and genetic diversity are positively correlated. It really is that simple.

This post is entirely wrong. 1) "Near extinctions" do not cause evolution and genetic differentiation. Mutation, selection and drift do. www.sciencemag.org/content/318/5858/1842.full 2) Humans do not have less genetic variation than other animals. We have considerably more than many. 3) Dispersal capability and behavioral adaptation do not reduce genetic diversity. 4) "Near extinction" otherwise known as a population bottleneck is generally not a gradual process. 5) Population bottlenecks reduce genetic diversity. 6) I think you meant population variation, which is positively correlated with effective population size. Large populations are diverse, with generally more rapid rates of evolution than smaller populations.