Humans are animals. We aren’t any more evolved than any other species, but we evolved down a different path from other species, just like foxes evolved down a different path than raccoons.We are not monkeys, but we share a common ancestor. We are primates, meaning that we have thumbs that can touch all of our other fingers (opposable thumbs). Our eyes are in the front of our faces, so we can see in 3D. We did not evolve from any of the other primates that are still around, but we came from species that lived millions of years ago and had several branches on their family tree. If you go back far enough, you would even find an ancestor that we shared with modern fish, but we didn’t evolve from any fish that are still around.

All living things can evolve. Evolution just means a change in how common certain genes are. The changes can be small. If populations get separated long enough, they can change in ways that eventually make them new species. Humans haven’t necessarily stopped changing, but it’s in very small ways. The longer the lifespan is in a species, the longer it would take to see a change. Humans are all one species. In order for humans to split into new species, a group of humans would have to be isolated somewhere for tens or hundreds of thousands of years, maybe some lost space colony someday will do that.

Having a big brain is a big part of being human, but that doesn’t mean that other species will get bigger brains (Some big animals already have brains bigger than ours, but for our body size, are brains are big and complex.) Having a big brain costs a lot of energy. Other species are successful by being stronger than we are, or smaller, or faster. Having a bigger brain might actually lower their survival. Birth is already difficult in humans because of our big heads.

You might be interested in studying human evolution more. Here’s a good site for that: click here

Human brains have been evolving for the exact same length of time as the brains of any other animal. They have, for whatever reason, not needed brains as complex as what we have. Why this is we don't yet know.

Evolution does not have a goal endpoint so animals do not have to constantly evolve. It is not as though human brains are the most evolved and all the other animals need is more time to evolve to develop human brains.

There are many animals that exist today that existed in almost that exact same form millions of years ago. They have not evolved because they are still highly successful and able to reproduce and continue to the next generation without changing.

The speed of evolution actually varies a lot, from very fast to very slow. It depends on how fast a particular species can reproduce, for example germs can reproduce faster than elephants, so germs can evolve faster. It also depends on how often mutations, or random genetic differences, occur in a species. The more mutations, the more potential for evolution.

Finally strong selection pressures can increase the speed of evolution. These can be big changes in a species’ environment that make individuals with a particular trait survive and reproduce more than others, resulting in the spread of that trait.

It is important to note that the brains of many other animals have undergone just as much evolution as the human brain, but in different directions. Each animal fits into, or is adapted, to its environment, and evolution does not “want” to reach any particular goal, like reaching the complexity of the human brain. Every animal faces its own set of problems, and so their brains are designed by evolution to try to solve those problems. So the brains of other animals are not evolving towards what our brain is like, unless the selection pressures change and result in an instance of convergent evolution, or when two different species evolve the same traits independently.

This is a fantastic question, and I believe it is an opportunity to clarify a major concept surrounding evolution. The most important thing to realize about all species of animals present today is that they are ALL equally evolved! They have all been evolving since the very first eukaryotic cellular organisms (cells with nuclei) evolved around 2.5 billion years ago. This is hard to understand at first, because many people say that humans are “more highly-evolved” than any other animal, but that is a common misconception. The big difference between humans and any other organism is that our brains happened to be our most evolutionarily-beneficial trait. Our brains have helped us survive throughout time, just like dogs’ noses, claws, and teeth help them survive.

However, it is still possible to measure the amount of time it took modern humans to evolve from their early primate ancestors, who’s brains were more similar to “animals” of today.

The first primates are reported to have evolved 75-100 million years ago.

Bipedal primates evolved about 7 million years ago.

Stone tool use began about 3 million years ago.

Fire use began around 1 million years ago.

The earliest cooking and clothes were both about 500,00 years ago.

Modern humans have been around for about 100,000-200,000 years.

So assuming that a species on earth today evolves such that their intelligence proves to be the most evolutionarily-beneficial trait (as opposed to flight, smell, or other physical attributes), then I would guess it would take at least a few hundred million years for that evolutionary pathway to result in a species with a similar intelligence to humans.

If you are at all interested, a Discovery Channel miniseries called The Future is Wild compiles ideas from many evolutionary scientists to try to depict what the future of earth might hold if humans were to leave the planet. They seem to suggest that one likely candidate for the new intellectually supreme species could be an ancestor of modern squids! (A fun thought. But this is of course impossible to know for sure.)

Animal brains are just as evolved as human brains right now. Animals have slightly different brains (and thus behavior) because each species has found its own way to survive its unique environment. Let’s talk about why that is:

Each individual in a species is born with some combination of their parents’ traits and some random new ones – for example, a bird may be able to fly slightly faster or have more spots on their feathers. If some of those traits make it easier to survive in their environment, that individual will live long enough to pass their traits to their children – in our example, that fast bird may be able to catch more food and the spotted bird may hide from predators more easily. This natural selection leads to change over time, a process we call evolution.

It is tempting to think that evolution is moving forward, toward some best set of traits, but that’s not the case. Evolution is simply change over time, with no preferred direction or best way to survive. The examples I gave above are very simple; in reality, not all traits directly contribute to survival, so they continue to be passed on at random. There are also many different ways to be successful in any given environment – think of the bird example: swallows survive by being fast while quails succeed by hiding. The environment can also change so different traits are favored over time. All the animals that live with us on this planet have survived and are equally evolved to live in their environment.

It is important to point out that humans have survived in part because of our ability to change our environment to better suit our needs. It is rare for a species to be able to do this on the global scale the way that we have. In changing the environment to favor us, we have made it difficult for some animals to survive. We are making these changes so fast that it is difficult for these species to change their survival strategies in response, and are in danger of dying out. That does not make those species any less evolved but it may make them extinct if we don’t take action to help them.