Belated response for you here
@Frank Dong if you haven't gotten one via IRC yet: Yes you need to submit a PR, but it can be just about anything, it doesn't have to be a complex issue. It could be adding a new unit test or even fixing a typo.
It is often better to reach out for live chat on IRC on more specific questions, as it can be easy to have a particular person miss a question on here. On IRC you can try reaching out a few times until somebody who knows can help you out - sometimes
we don't even know that some new person has the knowledge to fix something, so asking in the open can be a good strategy
Genome on plants and/or creatures is valid, yep. Just way easier on plants.