That is pure bolony. It is a necessary doctrine of evolution because after 100+ years nothing in the TOE can b e proven. To say that it has not been proved that there is more than 1 blood type is laughable. It shows your indoctrination has been successful
Look dude, how am I supposed to demonstrate to you what the academic definition of proof is when you reject the idea of reading posted sources AND absolutely will not take my word for it? You've made discussions with you so unreasonable that I'm considering just ignoring you on that basis. And I have NEVER ignored someone because of debate behavior before.
That there is more than one blood type can't b e disproved.
Sure it could: all the people of every blood type except 1 die, for example. Or, the entire time, our concept of blood type was the result of continuous incorrect assessments of the antigens on the surface of blood cells, and rejection coinciding with mismatched blood types is due to an independent factor that happens to be inherited along with those genes. Oh, you are definitely right that we observe antigens which correlate with the capacity to receive blood without dying, but it doesn't matter how consistent that relationship it, because the possibility that our interpretation is wrong remains.
That means it has been proved. It was not always know that there was more than one blood type.
Nah, you're just wrong when you state it "can't be disproved". You just don't understand that meeting your personal standard of proof and being proven academically are two different things. Things that seem to be absolute in science, such as why the sky is blue, aren't, there's just so much evidence supporting them that to suggest otherwise is silly. That's how it is with evolution: there is so much evidence supporting it that to claim otherwise is to bet on 0.000000001% chance rather than 99.999999999% just because the latter number isn't and can never be 100%.
What is silly is denying the obvious.
So obvious to you that HOX genes pertained to bone development specifically. So darned obvious that you were willing to state that was the case when you were just 1 Google search away from figuring out that's not what those genes pertain to.
First of all it is not my standard. When something can be tested and always
have the same result, it has been proved.
Nope, that's simply wrong, and I challenge you to find an academic source that supports you. Because guess what? I read sources posted by people. How about posting some?
Then why don't you cut and paste some evidence from one of these links and shut me up.
-_- every time I do you either refuse to acknowledge what is written or double down. Every. Single. Time. Still waiting on your response to the all female lizard species.
You look foolish not doing it---It is because you would if you could, but you can't.
Are you purposely ignoring every other conversation we have had? Who was the one that schooled you on what HOX genes do, because you not only didn't know yourself, but you didn't even look them up and decided to pull an answer out of your butt and made a fool of yourself? Twas I. Or, how about horizontal gene transfer, hmm? Gonna still deny that happens, even after I gave you over a page of information on it and even offered to give you the steps to an experiment so that you could see it in action for yourself. ASK. FOR. THOSE. DIRECTIONS. Post "Sarah, I want to perform a horizontal gene transfer experiment, please give me the directions" word for word, or admit that you aren't willing to ask for them.
But hey, you asked for this rather than convenient links:
f two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be
homologous.
To give one classic example, the forelimbs of whales, humans, birds, and dogs look pretty different on the outside. That's because they're adapted to function in different environments. However, if you look at the bone structure of the forelimbs, you'll find that the pattern of bones is very similar across species. It's unlikely that such similar structures would have evolved independently in each species, and more likely that the basic layout of bones was already present in a common ancestor of whales, humans, dogs, and birds.
Some homologous structures can be seen only in embryos. For instance, all vertebrate embryos (including humans) have gill slits and a tail during early development. The developmental patterns of these species become more different later on (which is why your embryonic tail is now your tailbone, and your gill slits have turned into your jaw and inner ear)^22start superscript, 2, end superscript. Homologous embryonic structures reflect that the developmental programs of vertebrates are variations on a similar plan that existed in their last common ancestor.
The small leg-like structures of some snakes species, like the
Boa constrictor, are vestigial structures. These remnant features serve no present purpose in snakes, but did serve a purpose in the snakes' tetrapod ancestor (which walked on four limbs).
Image modified from "
Rudimentary hindlegs spurs in Boa constrictor snake," by Stefan3345,
CC BY-SA 4.0. The modified image is licensed under a
CC BY-SA 4.0 license.
Sometimes, organisms have structures that serve no apparent function but are homologous to useful structures in other organisms. These reduced or nonfunctional structures, which appear to be evolutionary “leftovers," are called
vestigial structures. Examples of vestigial structures include the tailbone of humans (a vestigial tail), the hind leg bones of whales, and the underdeveloped legs found in some snakes (see picture at right)^33start superscript, 3, end superscript.
Analogous features
To make things a little more interesting and complicated, not all physical features that look alike are marks of common ancestry. Instead, some physical similarities are
analogous: they evolved independently in different organisms because the organisms lived in similar environments or experienced similar selective pressures. This process is called
convergent evolution. (To
convergemeans to come together, like two lines meeting at a point.)
For example, two distantly related species that live in the Arctic, the arctic fox and the ptarmigan (a bird), both undergo seasonal changes of color from dark to snowy white. This shared feature doesn’t reflect common ancestry – i.e., it's unlikely that the last common ancestor of the fox and ptarmigan changed color with the seasons^44start superscript, 4, end superscript. Instead, this feature was favored separately in both species due to similar selective pressures. That is, the genetically determined ability to switch to light coloration in winter helped both foxes and ptarmigans survive and reproduce in a place with snowy winters and sharp-eyed predators.
Like structural homologies, similarities between biological molecules can reflect shared evolutionary ancestry. At the most basic level, all living organisms share:
- The same genetic material (DNA)
- The same, or highly similar, genetic codes
- The same basic process of gene expression (transcription and translation)
- The same molecular building blocks, such as amino acids
These shared features suggest that all living things are descended from a common ancestor, and that this ancestor had DNA as its genetic material, used the genetic code, and expressed its genes by transcription and translation. Present-day organisms all share these features because they were "inherited" from the ancestor (and because any big changes in this basic machinery would have broken the basic functionality of cells).
Although they're great for establishing the common origins of life, features like having DNA or carrying out transcription and translation are not so useful for figuring out
how related particular organisms are. If we want to determine which organisms in a group are most closely related, we need to use different types of molecular features, such as the nucleotide sequences of genes.
Homologous genes
Biologists often compare the sequences of related genes found in different species (often called
homologous or
orthologous genes) to figure out how those species are evolutionarily related to one another.
The basic idea behind this approach is that two species have the "same" gene because they inherited it from a common ancestor. For instance, humans, cows, chickens, and chimpanzees all have a gene that encodes the hormone insulin, because this gene was already present in their last common ancestor.
In general, the more DNA differences in homologous genes (or amino acid differences in the proteins they encode) between two species, the more distantly the species are related. For instance, human and chimpanzee insulin proteins are much more similar (about 98% identical) than human and chicken insulin proteins (about 64% identical), reflecting that humans and chimpanzees are more closely related than humans and chickens^55start superscript, 5, end superscript.
Biogeography
The geographic distribution of organisms on Earth follows patterns that are best explained by evolution, in combination with the movement of tectonic plates over geological time. For example, broad groupings of organisms that had already evolved before the breakup of the supercontinent
Pangaea (about 200200200 million years ago) tend to be distributed worldwide. In contrast, broad groupings that evolved after the breakup tend to appear uniquely in smaller regions of Earth. For instance, there are unique groups of plants and animals on northern and southern continents that can be traced to the split of Pangaea into two supercontinents (Laurasia in the north, Gondwana in the south).
The evolution of unique species on islands is another example of how evolution and geography intersect. For instance, most of the mammal species in Australia are marsupials (carry young in a pouch), while most mammal species elsewhere in the world are placental (nourish young through a placenta). Australia’s marsupial species are very diverse and fill a wide range of ecological roles. Because Australia was isolated by water for millions of years, these species were able to evolve without competition from (or exchange with) mammal species elsewhere in the world.
The marsupials of Australia, Darwin's finches in the Galápagos, and many species on the Hawaiian Islands are unique to their island settings, but have distant relationships to ancestral species on mainlands. This combination of features reflects the processes by which island species evolve. They often arise from mainland ancestors – for example, when a landmass breaks off or a few individuals are blown off course during a storm – and diverge (become increasingly different) as they adapt in isolation to the island environment.
In some cases, the evidence for evolution is that we can see it taking place around us! Important modern-day examples of evolution include the emergence of drug-resistant bacteria and pesticide-resistant insects.
For example, in the 1950s, there was a worldwide effort to eradicate malaria by eliminating its carriers (certain types of mosquitos). The pesticide DDT was sprayed broadly in areas where the mosquitoes lived, and at first, the DDT was highly effective at killing the mosquitos. However, over time, the DDT became less and less effective, and more and more mosquitoes survived. This was because the mosquito population evolved resistance to the pesticide.
- Before DDT was applied, a tiny fraction of mosquitos in the population would have had naturally occurring gene versions (alleles) that made them resistant to DDT. These versions would have appeared through random mutation, or changes in DNA sequence. Without DDT around, the resistant alleles would not have helped mosquitoes survive or reproduce (and might even have been harmful), so they would have remained rare.
- When DDT spraying began, most of the mosquitos would have been killed by the pesticide. Which mosquitos would have survived? For the most part, only the rare individuals that happened to have DDT resistance alleles (and thus survived being sprayed with DDT). These surviving mosquitoes would have been able to reproduce and leave offspring.
- Over generations, more and more DDT-resistant mosquitoes would have been born into the population. That's because resistant parents would have been consistently more likely to survive and reproduce than non-resistant parents, and would have passed their DDT resistance alleles (and thus, the capacity to survive DDT) on to their offspring. Eventually, the mosquito populations would have bounced back to high numbers, but would have been composed largely of DDT-resistant individuals.
In parts of the world where DDT has been used extensively in the past, many of the mosquitoes are now resistant. DDT can no longer be used to control the mosquito populations (and reduce malaria) in these regions.
Why are mosquito populations able to evolve rapid resistance to DDT? Two important factors are large population size (making it more likely that some individuals in the population will, by random chance, have mutations that provide resistance) and short lifecycle. Bacteria and viruses, which have even larger population sizes and shorter lifecycles, can evolve resistance to drugs very rapidly, as in
antibiotic-resistant bacteria and
drug-resistant HIV."
Evidence for evolution
It's really annoying that you won't just click on the freaking links, but apparently have no issue reading the content as long as I copy and paste it. Why? Do you just giggle at how you inconvenience other people or what? That's literally the shortest post I could make on that matter, and I am immensely dissatisfied with the content. I'd need 10 pages to get everything I wanted, at a minimum. Do you really think it is reasonable for me to copy and paste rather than you clicking the link to the exact same freaking information?
All I need to know about genetics is that the offspring can't receive a characteristic not in the gene pool of its parents.
-_- just going to ignore every bit of text, pages and pages of information, that demonstrate this as false? If that were true, then bacteria grown on petri dishes that all arose from a single cell would all be identical always from that original cell, but they aren't, because mutation flipping exists. Horizontal gene transfer exists. Flipping dogs would all be the same otherwise, and a crap ton of genetic diseases wouldn't exist because they are dominant genes that kill before reproductive age.
You try to explain it with mutations and time, only validating you don't understand mutations either, and time will not change PROVEN scientific facts.
Coming from the guy that didn't know what HOX genes did until I told him because he'd rather take a haphazard guess than look it up himself.
