An introduction to the major groups of plants and animal traits which are the basis for classification. There are also tree diagrams of the ancestors to the major groups. Brainfood This is a site that serves as a study guide for different topics in the neurosciences. Check it out and see how you do. There is a reference guide, a description of the structures of the eye, models and math pertaining to the eye, info on synapses and neurotransmitters, and diagrams.
Some information is very technical.
You Try It' online activities. The Scientist is a publication for professionals in the life sciences. Registration is required but once you've done that, you can search their extensive archives, which go back to the 1980's, or look at the current issue. This site is a knockout. One of the best sites for biology.