but evolution doesn't just get rid of things when there is no use for them
like, we still have our appendix, but it doesn't do anything now
there is no reason at all for actively removing the claws; they wouldn't be a vulnerability for us
so I really wanna know why they went away, and became fingernails and toenails instead
honestly, I can't currently think of any animal that doesn't have claws, besides primates (and I think some of them do?)
bc of that, I also don't believe that we could have just evolved from a long-clawless race
Claws were lost by our evolutionary ancestors a very very long time.
I couldn't say for what specific reason, but there was definitely an advantage to that species to lose them.
Evolution comes about as a direct result of Natural Selection. There is no other way Evolution occurs.
What this means is that our ancestors came in contact with a selection pressure. A change in the environment which made it more difficult to survive. This could have been anything, from the introduction to a new prey or predator or food-source, or movement to a new geographical location.
Chances are, it was a new geographical location, likely with new fauna and flora.
This new environment is different to the old one. And in order to better survive it, smaller claws are better.
As a result, all those individuals of the population (not necesarilly the entire species) with larger claws don't survive. Or, atleast, not as many of them do, compared to the small clawed individuals.
So, when reproduction occurs, there are fewer large-clawed individuals available. So they fail to pass on their genes which code for large claws.
Instead, more smaller clawed genes are passed on.
The next generation of individuals now have (on average) smaller claws than the previous generation.
The need for small claws is still prevalent, so even those who have smaller claws than their parents, may be at a disadvantage. So, the largest clawed individuals of the new generation are less likely to survive, and fewer of them make it to reproduction. A new generation is bred with even smaller claws.
This continues for a long time, as smaller-clawed individuals are constantly selected for by the selection pressure.
The chances here are that the selection pressure is the presence of fruit as a food source.
Claws do not make it easier to reach for fruits, or to climb to them.
So, claws are selected against by Natural Selection, and slowly overtime, the population you had originally will develop to no longer having claws. It's a new species. There could however, be populations of the original species still alive, which did not enter or encounter this new environment.
This would be where the evolutionary line splits.
Let's also just note, that it is entirely possible (I don't know all the fossil records, so I couldn't say for sure), that after a species has lost its claws via evolution, it could encounter a new change in the environment.
One which sets up a new selection pressure. One which results in larger claws being selected for. THe same happens as above, but this population slowly develops large claws again.
It's entirely possible for traits and properties of organisms to die out and then to re-emerge later.
If you're thinking of animals that don't have claws, then consider these:
Horses.
Zebra.
Elephant.
Giraffe.
Sheep.
What your problem is, is that you're thinking of predatory land animals, primarily mammals.
In the mammalian class, natural selection has pressed over time (generally) for predatory animals to develop the use of claws.
This is because claws are one of the most efficient weapons in hunting other animals.
They allow you to rip and tear and slash at other animals in order to kill or fight.
The difference occurs when you hit the Herbivores.
Herbivores don't eat meat, and so generally don't have claws, as they offer no advantage whatsoever.
Instead you gain hooves and flat feet, which are simply feet adapted to their specific environments. Unlike pad-footed animals with claws, which have the pads to provide room for their claws.
And where you confuse yourself here, is when you think of animals like the Homo Sapiens (us), and other primates.
Humans can eat meat. So, as a predatory animal, you would expect us to have large sharp teeth and claws, for hunting other animals. But that's not so.
Humans are omnivorous. We can eat meat, but we can also eat plant life. Leaves, fruits, vegetables, certain grasses, etc...
Our species, and close ancestors, have been omnivores for a very long time.
Plant life is much much much more common than meat.
As a result, our ancestors spent a large amount of time in environments where fruits and plants were the most common source of food. So, natural selection pressed in favour for advantages to eating these. This includes long arms, opposable thumbs, flat grinding teeth, a lack of claws in favour for more dexterous fingers, shorter hair, and the ability to sit/move/walk vertically.
So, when human beings and their other hominid ancestors arrive on the ground, they have millions of years of herbivorous adaptations to them.
But, we're capable of eating meat. It's not however, our primary food source, and never has been.
Mankind have always foraged for food. We might hunt meat at times, but we could never rely on it as our primary food source.
Because men are not strong or fast enough to do so.
But that doesn't mean we'll develop advantages to do so.
Because of our ability to rely on plant matter. Regardless of if a population of humans is too weak to hunt for meat, it won't die out from a lack of food, due to plant matter, so no selection pressure is created for the gain of predatory adaptations.
But, men are reasonably good hunters. And this is due to two unusual abilities. The first is shared with a few other species (primarily our close evolutionary relatives), but the second is unique in it's complexity to us.
We can use tools, and we can communicate.
Our use of tools allows us to be predators without predatory adaptations.
We do not need claws, when we have daggers. Whether stone or bone or metal, it's as good as a claw.
We do not need to be fast, when we have spears and stones and arrows.
We do not need speed, when we can create traps to catch smaller herbivorous animals, like rabbit or bird or fish.
We don't need lots of fur, when we can use the skin of animals, or fire, to keep us warm.
And we don't need to be the absolute best in all these regards, because we can communicate.
Our ability to talk to each other provides the perfect level of communication between two individuals that we can expect to ever see. We can devise plans for hunting, or foraging, or farming.
Evolution doesn't just get rid of things when it's no longer required.
Which is true.
Evolution occurs as a result of Natural Selection. Meaning that for a trait to develop across an entire species, or to be removed, there has to be an advantage to it doing so.
The Appendix hasn't gone yet, because despite it being useless (as far as we know, although there is some study suggesting it's a home for useful bacteria in digestion), it does not impede us in any way.
People with bigger appendixes do not die, or are not more likely to die, than those with smaller appendixes.
As a result, the genes for having an appendix, or a large appendix, do not get selected against, and they remain within the gene pool.
But, as said above, the difference between the appendix and claws, is that claws provide a disadvantage, when trying to live in certain environments.
Namely, a herbivorous environment. They don't make it any easier for getting fruits, nor they do make it easier to live in the trees, or to utilise tools. So they're selected against.
