why do  offspring of sexually reproducing organisms resemble both parents?why are they not identical to one?
916835
Because they have DNA from BOTH parents.  That is the point of sexual reproduction: mix so that each individual is a bit different, an experiement in optimisation, and has a little bit of both "successful' (since they were able to reproduce) parents.
560072
The origin of males and females as we know them is an evolutionary enigma.  Asexual reproduction produces a much higher output, requires no gender, and only one individual.  The most widely-accepted reason for sex is that it provides a larger amount of genetic variation.  Instead of the genetic material of one parent organism, sex utilizes the genetic material of TWO organism.  Greater genetic variation insures that the species as a whole will have a greater chance of adapting to new environmental pressures, such as disease.  Thus, sexual reproduction evolved and gender was born.  Naturally, if two members of different genders are required to produce more of the same species, it is essential that these genders are attracted to one another.  If you have a type of animal in which males and females have no sexual interest in each other, the species is likely to go extinct once those initial animals die, due to a lack of new generations.  Bottom line: Human individuals who are attracted to the opposite sex are more likely to produce offspring than those individuals who are not, and these offspring will tend to inherit the parents' same attraction to the opposite sex.  Years of natural selection on species that reproduce sexually spawns a species characterized by the majority of any given gender being attracted to the opposite sex.
569475
Yes, because one of the characteristics of life is the ability to replicate, or reproduce, and they definitely do that.  Another is the ability to move freely and independently, and they also do that.  Check the website below for other information.
1187693
As you can see, the people who answered this question don't get what you asked.\n\nIf adam and eve were real, the intercourse between them would have been fine, but the intercourse between their children wouldn't have.\n\nFurthermore, it is enirely impossible for a species to have been wholey propogated from two individuals.  The resultant inbreeding would have extinguished the species.  Or, at least, they'd be too retarded to even know how to breed.
866248
Mitosis produces two cells which are genetically identical to the original one. There is no exchange of genes between two organisms, and so mitosis is a type of asexual reproduction.
141789
The obvious advantage of asexual reproduction is that you don't need other members of your species around to reproduce.  This is a really good thing if you want to go in and colonize someplace like a island, or maybe a recently-burned forest.  Or if your species isn't doing so great and there's just no one else around.\n\nFrom an evolutionary perspective, the 'goal' of an organism is to pass it's genes on to the next generation.  In sexual reproduction, each organism only gets to pass half its genes to its offspring.  In asexual reproduction, the parent gets to pass all its genes to the offspring.  That's great if the parent is perfectly adapted to its environment.  The problem is, it's the evolutionary equivalent of putting all your eggs in one basket - if something chances and the offspring are no longer well suited to the environment, chances are they'll all die instead of just a few.
284515
The manner in which the aliens breed is going to be the same regardless of what species they breed with.  Yes, the alien baby will take on certain aspects of it's birth parent; however it will never not have acid for blood or not shed skin as it grows or not have a double mouth or not breed through laid eggs.  Therefore it's a dominant species with absorbs only the physical genetic aspects of a host.  It is and always will be an alien.  It might look a little like a predator but it's an alien.
812119
asexual reproduction doesn't require two partners in order to reproduce...sexual is the opposite.  It requires two creatures of the opposite sex in order to reproduce.
1131654
OK, *some* twins are genetic clones, in that they have identical DNA because they come from a single egg and a single sperm.  Most twins are not genetic clones and are in fact fraternal, coming from two different eggs and two different sperm.\n\nAs the parent of identical twins, I can tell you that they have a lot of differences.  They don't "share a soul" so that they can communicate in some romanticised twinspeak thing, although they do relate to each other extremely well and often feel similar emotions, but then they are usually doing the same activities and having the same experiences, so there is nothing mystical about that.  \n\nTHey are each an individual and they have their own individual likes and dislikes.  They like a lot of similar things, like their favouirte colour and games, but then that makes them similar to just about every other 3 year old girl on the planet too.\n\nBut lets get right to the point:  God caused them to come into being.  God gave them each their own soul.  They have the right to be recognised and valued as individuals.  Twins are very special and identical twins are rarer and so thought of as even more special - it is always a novelty for people to see people who look exactly alike.  But as a parent of two other children who are not twins, I can also say that every single person born is just as special.  Lets not bestow multiple birth children with mystical qualities.  Lets just let them be kids.  They get enough unsolicited attention and advice as it is.
463700
Contrast:\n- Asexual reproduction is done with only one individual or cell in the process (called mitosis) and usually involves splitting or grafting of the original organism.\n- Sexual reproduction occurs when one cell fertilizes another (sperm and egg are the most common terms for it) and it usually results in a more stable gene pool because more chromosome combinations are possible.\n\nCompare:\n- They both involve reproduction at the cellular level.\n- They both involve some manner of genetics (either splitting or joining)\n- They both produce offspring.
1065164
The cells from two separate eggs (twins) can combine into one whilst in the mother's womb - thus one child is born but has two dna's instead of one
936845
asexual involves only one parent and the offspring are genetically identical to the parent.\n\nSexual in volves two people and is what humans do.
990688
There are many hundreds of thousands of species of unicellular algae that reproduce sexually. \n\nWe have some fossils of brown algae that were in the process sexually reproducing dating back to well before the first multicellular life evolved. We know this because such alage produce silicons 'skeletons' that preserved their structure. \n\nSo we can be absolutely certain that the first sexually reproducing organisms weren't multicellualr.\n\nAs for which the first were, we really can not know. It's almost impossible to tell from fossils whether how a unicellular organism reproduced if it doesn't produce a solid skeleton, and solid skeletons evolved late.
911131
People are born gay. It is scientific fact that there are biological differences between homosexual and heterosexual people.
457511
won't happen, parthenogenetic offspring are genetically identical to their parent, i.e. female
995656
Segregate two populations of creatures into separate environments, and see if evolutionary differences between the two populations occur over many generations. That's the sort of experiment the bible thumpers would have to twist logic into a pretzel in order to refute.
140194
>>>>>were we really monkeys years back.\n\nNo. Humans were never monkeys, nor were any of our ancestors monkeys.\n\nHumans and other apes share a common ancestor with the monkeys, but that ncestor was not itself a monkey.\n\n\n\n>>>if so these days why monkeys do not give birth to humans?\n\nI must be misundertanding that question. It can't be as silly as it sounds.\n\nMonkeys don't give birth to humans because they are monkeys. What other answer could there posibly be? The offspring of an organism inherit its genetic structure and hence its gross physical appearance. Monkeys are genetically monkeys hence their offspring are genetically monkeys.\n\n_____________\n>>>>chimps and humans ...would not be able to procreate...\n >>>>because of their different sets of chromosomes.\n\nThere  is no scientific basis to that claim whatsoever. Nobody knows whetherhumans and chimps are interfertile because nobody hs ever tried to find out.\n\nDiffering chromosome counts has never prevented two species reproducing. The world is full of animal species with differing chromosome counts that are perfectly interfertile and regularly interbreed.