Why is there (apparent) order when laws such as thermodynamics and entropy (not to mention 3 or 4 mass extinction events) say that the earth and its solar system should be chaotic?

Since this is the homework help section, I cannot give you a straight answer, but I can point you in the right direction, so that you can go and find the answer through your own research.

While the second law of thermodynamics does indeed dictate that entropy (i.e. disorder) can only remain constant or increase, making things more “chaotic” over time, this law does not just apply to any system, but only to systems that have a particular property. Can you do some research and find out what that property is? When you do, the answer to the original question will become immediately apparent.

The answer is probably a 'closed' system but I don't understand that as all systems appear to be interdependent.

Well spotted

And that’s exactly the point - most systems aren’t closed ones, and that is why there can be circumstances in which we find highly ordered systems, instead of just random disorder. Because, unlike in closed and isolated systems, in an open and interacting system entropy can decrease locally. That is because entropy is not an absolute value, but a relationship between systems, and it is also observer-dependent. 

For example, in our solar system, the sun is a source of low entropy relative the rest of the system, so in net terms heat flows only in one direction - from the sun to the planets. At the same time though, its entropy is high when compared to the environment in the early universe. You get the idea.

Thanks Markus