What exactly is the theory of evolution?

i'ts the idea that we come from monkeys n other animals n we turned into humans a long time ago. i dnt no how i feel about it but if the scientists think so then i think its prolly true

Lazy to me, is not a gene.  Neither is being physically fit.  
Body types are genes, but to be physically fit you have to do that on your own.
Laziness is just a characteristic trait.

Awesome question, terrible first answer.  I really wish I could answer that, you've got me thinking now.  Oh and if you don't think being physically fit is genetically influenced take a look at the NBA.  Not trying to be racial here but there's really no denying it.

Traits like laziness or physical fitness are not controlled entirely by genetics. The theory of evolution says that species evolve by a process of decent with modification(mutations) and natural selection. The word "Darwinist" has no scientific meaning. Darwin's  theory has been substantiated by myriad scientific observations since he first proposed it 150 years ago. At the time he proposed it the science of genetics didn't even exist.

It is said that laziness is moving technologies.

Also, you are lazy while you have food (cats are said to be lazy when they are full).
Once you are hungry your physical fittness will help you to survive. You are fed - you are lazy again.

Laziness in humans today is mostly non-greediness (you won't move a finger for extra-stuff).  
Laborholics on other hand are either extreme "hunters" by ancient standards or just have gaps in their life which they need to fill with work.
So, you example is not perfect.

However

Advantageous trait that over-compensates disadvantageous trait that is genetically or non-genetically linked will help its owners to survive, reproduce and continue their lineages.
Many advantageous traits have a cost.

Genetically: HIV virus develops drug resistance at the cost of its replication capacity. WHile being less fit in general, drug resistant viruses will outlive those which was not mutated

Non-genetically: bipedalism causes difficulties in child births but has so many advantages that it got fixed forever in human lineage.

Sexually: bright and cocky males, for example birds, have more chances to fall prey than unremarkable males. Nevertheless, female preferences keep bright ones to spread their genes and discard runts.

Natural selection works on the level of individuals, not genes. If it were not for genetic recombination, your worries would be well founded. But due to recombination, eventually the two traits will be uncoupled. It may take longer, ie more generations, for resolving linked genes, but eventually the most fit genotype, namely "physically fit" and "not lazy" to become the main/only genotype in the population.

Of course this assumes that being "lazy" is necessarily a negative trait! I can think of many a situation where being lazy - or perhaps one who wisely conserves one's resources - is likely to survive better than a less lazy individual. Being lazy AND fit may well be the way to go!

Well first, evolution is about *heritable* traits.

So you would first have to establish the degree that being "physically fit" and "being lazy" are both heritable traits.  

Being "physically fit" is something largely acquired by exercise, not just genes ... people aren't just *born* "physically fit."   You may have a *predisposition* to be able to become physically fit with less exercise than it takes another person.  But it is not as simple as being born with the "phycisally fit" gene.

Being "lazy" is also more of an acquired trait than a genetic one.   It can be passed down in families through *behavioral modeling*.   But there is no evidence (unless you know of some) that "being lazy" is purely, or even mostly, genetic.


But OK ... for the sake of your question, lets assume that being "physically fit" and being "lazy" are both purely genetic traits.

In which case, your first option is the correct one.   Darwinian evolution is about survival of individuals ... and individuals are "bundles" of genes.   If trait A ("physical fitness") is advantageous, and B ("laziness") is disadvantageous ... then trait B may survive just fine in the population as long as there are lots of people born with *both* A + B, and the advantages of A outweigh the disadvantages of B.

Evolution is a blind process who bangs away against the metaphorical anvil of living animals. There is a misconception in evolution that you seem to have fallen into.

Evolution (via natural selection) is not "the strongest survive" it is more "the ones who can have more babies have more babies". This is then applied to survival, because if you survive longer you can usually have more babies. But this is not always true. Say you live to be 30 and die because you were lazy and sat on a couch eating fritos. If you hired a hooker every week for a year and got them all pregnant with your child, then you are winning the evolutionary race.

However, in this respect you have to realize what you are "selecting". In the above mentioned case, natural selection would be favoring an attitude (only if it is hereditary) that suggests hiring hookers is perfectly fine. You are not selecting for laziness or the desire for fritos. Evolution only cares about one thing....who is going to pass their genes on to next generation.

To conclude, evolution only asks two questions. Can you have lots of babies? Can those babies have lots of babies? If both are yes then natural selection is on your side...for the moment.