The arthropods were assumed to be the first taxon of species to possess jointed limbs and exoskeleton, exhibit more advanced receptors in the form of eyes, and develop various chemoreceptors. Since they possess such desirable features, their survival over the long term is apparent by their genetic diversity. Learn more elaborate details about arthropod evolution in this tutorial...
Neurons generate electric signals that they pass along to the other neurons or target tissues. In this tutorial, you will find the basic structure of a neuron, the different classes of neurons, and membrane potentials. It also includes the structure of the nervous system...
Plants and animals need elements, such as nitrogen, phosphorus, potassium, and magnesium for proper growth and development. Certain chemicals though can halt growth, e.g. herbicides in plants, or affect normal physiological activities, e.g. alcohol. For more info, read this tutorial on the effects of chemicals on plants and animals...