Where does the web designer's role finish and the SEO's start? When does the SEO's role finish and the conent writers' start? What is my job? There is the research. There is the disemination of knowledge to others...
I would say that a good designer skilled with css should be able to build a website asthetic from any underlying structure provided by the SEO.
The web designer's rol will finish only until your website expired, because you have to always update the content of your pages. SEO's role starts from the point your planning of your website, at that time, though content and design is most important, things like keyword, meta tags, tilte, internal link structure are all related with SEO. You job is to hire the two crews to work for you, and monitor the results and status.
It really depends on your company. I struggle with this myself. If your company has a good webdesign team, SEO should be on the agenda. If not, it's in your best interest to be the SEO spokeperson for your company. That does not mean SEO will always be a top priority. Just that in discussions and design and planning it should be one of the issues taken into account.
SEO start with simple link building and basic terminologies of SEO like the definition of SEO, the methods used, link building and link popularity, and content optimization. Link building is a method where SEOs submit the site's info to directories to have a link in directory sites.
IMO, designers are the one who does the website designs from the term itself. while SEO is optimizing the website done by the web designers, to reach the desired rankings in the SEs. SEO is concern on bringing good traffic for the site, by link building, content optimization and many other SEO processes.