Biology Surfing Lessons

If you are here, you're probably intimidated by this whole "Surfing the Internet" thing. Well, there's no better time to get wet! Fear not land-lubber, the Internet, a worldwide network of computers, is getting easier to navigate with the help of new software. This primer is not intended to cover every aspect of the Internet, but it will introduce you to aspects of the Internet you'll encounter at this site, including the World Wide Web, Gopher, e-mail, and Usenet.

If you are a complete beginner, use the scroll bar to take you through the lessons below this introduction. If you know just what subjects you need help with, click on the topic title to the left to jump ahead.

What is the World Wide Web?

What is a Uniform Resource Locator?

What will I encounter on the WWW?

How do I navigate the WWW?

How do I use a website address I've seen or heard about?

How do I find things on the Web?

I want to know more!

I want to see the glossary.

Go Biology Surfing

The Internet offers several approaches for accessing stored information on other computers and communicating with other people. One of the best known and widely used aspect of the Internet is the World Wide Web (WWW), a hypertext-based system that lets you find and access Internet resources.

What is hypertext? Well, you've probably already used it--it's those highlighted words that have been coded to take you to another page (or section of a page) when you click them. For instance, if you want to see the definition of any highlighted word on this page, like hypertext, click it to go to the glossary. When you're done reading, click the "back" button on your browser to return to this part of the page. Images or areas on a larger image can also be linked to a web page.

There are other methods of accessing information, like FTP and Gopher, but WWW documents, commonly called web pages, are what most people who "surf the Net" are browsing. Why? First of all, while Gopher and FTP files must be accessed by clicking appropriate directories in descending order, hypertext allows for flexible access of documents relevant to a certain page. Secondly, most WWW browsers worth their salt can access these other services, as well as e-mail and newsgroups, with a more understandable interface. Lastly, the advent of sophisticated web browsers allows web pages to display images, play sounds, and be truly interactive, whereas Gopher and FTP "pages" are only text--images, movies, and applications must be downloaded and played later.

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The URL, or Uniform Resource Locator, indicates the location of a file on a certain computer and how to get it. Look at the top of your browser--you should see

http://www.brookscole.com/biology/member/student/surfing/lessons.html

This is the URL of this page, Surfing Lessons. A URL tells your browser to contact a certain computer (www.thomsonlearning.com), ask for a certain file (lessons.html) sitting in a certain subdirectory (rcenters/biology/member/student/surfing/), using a specific protocol (http). It will always* take the following form:

protocol://internet_address/path_name/file_name.file_format

Protocol: The protocol you'll see most often while surfing is called Hypertext Transfer Protocol, or http. You may also see Gopher or FTP (File Transfer Protocol).

Internet Address: The Internet address is the name of the computer you are accessing. It will always have a suffix specifying what type of site your are visiting--most often either com, edu, org, gov, or net. Foreign addresses have an additional two-letter country abbreviation, such as uk for the United Kingdom. There is a numerical equivalent to this text-based address, but you will rarely see that.

Path Name: The path name may contain several directories, each separated by a slash.

File Format: The file name is usually followed by a period ("dot"), then the name of the file format (also refered to as the "extension"). The most common file format is "html", which means a file is a text file coded in hypertext markup language. You may also encounter "gif" and "jpg" (graphics), "mpg" and "mov" (digital movies), "aif" and "wav" (digital sound files), and "swf", "dxr" and "ra" (browser plugin-specific files).

*There are two exceptions, "mailto" and "news". The URL scheme for sending e-mail is:

mailto:username@hostname

and the URL to access a newsgroup is:

news:newsgroup

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Web pages can contain hypertext, images, animations, links to download movies and software, forms to fill out, buttons to press, and interactive media. They can be organized as flat pages or in tables or frames. Web pages can also use other protocols to jump to Gopher or FTP sites, e-mail addresses, and newsgroups.

You may find that you are unable to experience certain media, see certain formats, or access other protocols. This is because:

1. Web browsers vary in their ability to understand and interpret the language behind the web pages that you see. The language is called HTML, and like a real language, it is evolving so that it can describe more complex behavior to your browser. Some browsers are unable to display graphics (like Lynx), some are unable to display frames and tables, and some are unable to run Java applets or understand JavaScript (early versions of Netscape Navigator and Internet Explorer). It is generally recommended to download the latest version of the browser you prefer using.
   
   
2. Web browsers also use auxilliary applications, called plug-ins, to display certain media. Plug-ins you may encounter at this site include Shockwave (multimedia), RealAudio (streaming audio), and RasMol (3D molecule viewer). Sites that require a particular plug-in will usually direct you to a page which tells you how to download and install that plug-in.
   

Some sites may ask you to register or to subscribe before you are allowed to browse their pages. Often, they want to know more about you so they can gather information about their visitors and the people using their products. Certain sites, like the Encyclopedia Britannica, charge for their services. We will avoid linking to commercial sites.

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You've probably already figured out the first half of this problem--simply point and click on hypertext or graphics that you are interested in. If you have never come across a page containing frames (it will look like two or more pages separated by a bar), read the description of how to navigate a page with frames after reading this section. Navigation on the web can be divided into site-based navigation and browser-based navigation.

Site-Based Navigation: If you come to a website at its home page, you will see icons or text directing you to ever increasingly detailed information. Websites are collections of web pages. Web pages are the browser's manifestation of several files on a computer called a server. Just as files on your computer are organized in directories (represented by folders on the Macintosh and Windows), so are files on a server. As you get deeper and deeper into a site, there should be icons directing you back to higher levels. If you ever link to a page at one of these bottom levels, and wonder what site you are at, you should look for an icon or text that says "home" or "main." Clicking this will take you to the home page. If you are unfortunate enough to find a page that lacks any site-based navigation, you may still find your way up to the home page by lopping off the end of the URL, leaving only the protocol and Internet address (like http://www.netscape.com/).

Browser-based Navigation: As you travel from page, your browser is leaving a trail of breadcrumbs so that if you decide to go back, you can retrace your steps. If you decide to go forward again, you can also retrace your steps up the path in the last fork you traveled. There are several ways of travelling back and forth with a browser. Netscape Navigator, for instance, has five.

To move one page at a time,

1. Click either the back or forward buttons at the top of your browser
   
   
2. Hold your cursor down until the Back and Forward options appear in a pop-up menu. Scroll, select, and release.
   
   
3. Select Back or Forward from the Go menu.
   
   
4. Use the keyboard commands specified in your Go menu.
   

To move by several pages.

Select the name of the desired page from the Go menu.

Most browsers also allow you to bookmark a site, so that you can select it from your bookmark menu (also called hotlist or favorites by other browsers) and jump there immediately, instead of typing in the URL all the time.

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It seems like every company suddenly has a website address listed at the bottom of their print or TV ads. To visit a website, find a spot on your browser that says "location" or "address," and type in the URL. You may even hear an ad on the radio say "Visit us at www-dot-stuff-dot-com." "Dot" indicates a period. Try alternate spellings if your URL doesn't seem to work. If you are visiting a website, be sure that your URL starts with "http://", which radio ads sometimes leave out.

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If you want to find pages about a certain topic or a site belonging to a certain organization, you need to find a good web index. These web indexes vary in their scope and the depth of information they provide about a site, but all are searchable by keyword.

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Well, this was just an introduction to the Web and the Internet. We will also provide links to more in-depth, online material. For now, try searching or browsing this directory from Yahoo: Internet. U. C. Berkeley provides another excellent online tutorial with helpful illustrations

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