okey, i'm feeling like giving this a try. warning! wall of text incoming:what is evolution?
it took a long time before people realized that evolution might even be a thing, and it took way longer for most of the scientific world to agree with it. so instead of saying 'evolution is true', and then trying to convince you, i'll start with a bunch of observations done by scientists which i hope you'll agree with. quote me if you disagree with a part, and explain why you think its not true:
well, this is pretty much a given. there is variation within a species. everybody has a different length, hair color, how easy you catch diseases, etc.
it appears that children always look something like their parents. if two parents have red hair, then their child will probably also have red hair. a long kid often has at least one long parent, etc. so the first observation is that we inherit traits from our parents. we now know that this is explained mostly by our DNA. we get genes from dad and from mom, and you'll be a mix of both parents.
even though we would hope that our dna stays perfect, this does not always happen. sometimes, our dna gets mutated. http://en.wikipedia.org/wiki/Mutation
is a whole article about this, but for example radiation can sometimes break down a bit of our DNA, or while making a copy of the dna(cells do this any time they split up) a mistake can happen with the copying, and a part of the dna gets copied twice. whatever the reason, sometimes dna does not copy perfectly. a great example of this is the down syndrome: http://en.wikipedia.org/wiki/Down_syndrome
someone with the drown syndrome has an entire extra chromosome. not just a few genes but an entire chromosome got copied twice. the parents of a child with down syndrome often have normal dna(without the extra chromosome), so this shows that it is possible for a child to have a mutated dna which is different from the parent.
4. (Natural) selection.
this one is easy. not everybody has the same chance to survive and have children. modern humans aren't the best example here, so lets take a look at several animals were this happens(it happens with every animal though, but here are some examples): with prey animals, the weakest animals of the herd are often the first killed by hunting animals. thus, they don't grow up to have kids. or with migrating birds, only the strongest birds can survive the migration. but it is not only about dying: with some animals: only the alpha-male is allowed to have sex with the woman. thus, as some animals are alpha-male at one point, and some are not, then those alpha-males obviously have a greater chance to produce offspring.
now, with these four characteristics, we will have the basics of evolution. variation, heredity, mutation, and natural selection.
within a generation of children, there is a lot of variation in the genes(and thus in the external appearance). not all of these children will survive into adulthood and have children. but it is not up to random chance who survives. with natural selection we can say that some children have a bigger chance then others to grow up. thus, if a certain gene gives you an advantage, then not having this gene means you'll be more likely to die, and in the next generation, a greater percentage of the children will have that gene, because they inherit it from their parents.
for example, if a population of butterflies has a simple gene which makes them black if they have it, or white if they don't. if half of the population has the gene, then most likely around half of the children will have it too. but because they live in a field with white flowers, the white butterflies are harder to see by predators. thus, while 3/4th of the white butterflies survive, only 1/2 of the black ones do. so next year, the children will have more whites rather then black butterflies.
now, before having seen any fossils, we have found several characteristics of animals, and realized that this will lead to evolution. given enough time, we have found no limitations to how far this evolution goes, all the genes can mutate, hell, a new kid can even have an extra chromosome. there is no difference in how macro or micro evolution occurs. the distinction is irrelevant so far. once a group of animals has mutated far enough, there is nothing which suddenly causes them to stop mutating, they just mutate further.
now obviously, we have proposed a way of how evolution happens, but it would be a rather weak theory if we could not find evidence of this happening. to support this theory, we should look for examples in the real world. luckily, we found lots of them, and here are only a few examples:
-Dogs. the first dogs were simply tamed wolves, but because we humans selected the wolves we wanted to breed(we took natural selection in our own hands), we eventually ended up with all these different breeds of dogs. most of them are only several hunderd years old, and thanks to dog breeding and evolution we've ended up with a gigantic list of dog breeds: http://en.wikipedia.org/wiki/List_of_dog_breeds
-a famous example, Darwins finches: en.wikipedia.org/wiki/Darwin's_finches , a great number of different birds who all look alike.
-the human development of different forms of wheat. http://en.wikipedia.org/wiki/Wheat#Origin
the wheat we started out with 10.000 years ago is nothing like the wheat we eat and grow right now.
- the bacteria e.coli who have been evolving under observation for over 20 years: http://en.wikipedia.org/wiki/E._coli_lo ... experiment
however, instead of just listing examples and more examples, i think we should look at the broader picture.
by now, we have analyzed the characteristics of millions of plants, animals, and bacteria, and even examined their DNA.
now IF the evolution theory is right, then that would give us a great way to organize all these plants and animals.
and in fact, this appears to work brilliantly. by assuming the theory is right, scientists were able to organize ALL living creatures on earth.
here is a catalogue in which biologist are trying to put all known living creatures: http://www.catalogueoflife.org/col/browse/tree
for example, the Animalia
(the group of all animals), has several subdivisions, one of them is the Chordate
(this is the group that includes *all* species which have a notochord
, this includes all mammals, fish, amphibians, reptiles, birds, salps, sea squirts and lancelets.), in this group you have the subgroup of mammalia
, simply all mammals, all creatures which use breastfeeding. within this you have the order of the primates
, which includes all, well, primates, monkeys and the like. within this order you have the family Hominidae, which includes only those closest to us, the gorrilas, orangutangs, chimpanzees, and, under the genus "homo", us homo sapiens.
we have been capable of organizing every living organism(and, thanks to fossils, a lot of dead ones) in one organized form, and in it you can see groups which share the same traits, from very general attributes(all animals that have a spine fall in the group of Chordate), to more specific attributes(all mammals use breastfeeding, but all mammals also have a neocortex in the brain).
you can go and ask for a specific example of an animal between a dinosaur and a bird, but you can also observe the following:
-certain dinosaurs had feathers: http://en.wikipedia.org/wiki/File:Micro ... lotype.png
(look at the white arrows)
-hollow bones. both certain species of dinosaurs and birds have hollow bones.
-the bones and look of certain smaller dinosaurs.
-the similarity in DNA.
we wouldn't even need a sample to figure out that bird and dinosaurs are closely linked.
but since you asked for it:http://en.wikipedia.org/wiki/Microraptorhttp://en.wikipedia.org/wiki/Sapeornishttp://en.wikipedia.org/wiki/Buitreraptorhttp://en.wikipedia.org/wiki/Hesperonychushttp://en.wikipedia.org/wiki/Rahonavishttp://en.wikipedia.org/wiki/Unenlagiahttp://en.wikipedia.org/wiki/Velociraptorhttp://en.wikipedia.org/wiki/Graciliraptorhttp://en.wikipedia.org/wiki/Troodontidaehttp://en.wikipedia.org/wiki/Anchiornishttp://en.wikipedia.org/wiki/Utahraptorhttp://en.wikipedia.org/wiki/Adasaurushttp://en.wikipedia.org/wiki/Tianyuraptorhttp://en.wikipedia.org/wiki/Sinornithosaurus
the thing is, everything fits perfectly together by assuming evolution works, we can find certain genes and what their function is, see that species that have this gene have the function, we find common ancestors of species, we've observed evolution in the lab, etc. etc.
basically, if you assume that evolution works, the whole world around you makes perfect sense, while if you assume evolution doesn't work, you simply have no explanation for how all these animals are linked together, and how we can link natural selection, mutation and variation so easily together. and why would evolution not work? we have described a system for how it works, and we know that all the seperate elements of this system are in nature, and we've even seen evolution itself happen on a smaller scale. all the evidence in the natural kingdom points towards evolution.