pattern formation
(Science: cell biology) One of the classic problems in developmental biology is the way in which complex patterns are formed from an apparently uniform field of cells.
Various hypotheses have been put forward and there is now evidence for the existence of gradients of diffusible substances (morphogens) specifying the differentiative pathway that should be followed according to the concentration of the morphogen around the cell.
Human consciousness and behavior are an interesting topic since they are determined and controlled by the brain. Consciousness can be defined by behavior or by electrical pattern of brain activity. Read this tutorial to learn about brain activities, such as sleep, attention, emotion, motivation, consciousness disorders, learning, and memory...
Plants, like animals, produce hormones to regulate plant activities, including growth. They need these hormones to respond well to their environment and to sustain growth, development, and dispersal. Plant biologists recognize five major groups of plant hormones: auxins, gibberellins, ethylene, cytokinins, and abscisic acid. Find out in this guide the importance of each hormone in the life of a plant...
The circulatory system is key to the transport of vital biomolecules and nutrients throughout the body. Learn about the different components and functions of the human circulatory system dealt with in detail in this tutorial. The lymphatic system is also elucidated elaborately here...
Explore why New Zealand has such unique flora and fauna, and learn why long periods of geographical isolation. This lesson introduces the country's endemic species, ecology, and geology. Learn why long periods of geographical isolation have led to a large number of endemic species - native species that are not found anywhere else...
Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this tutorial, various plant processes are considered in more detail. It also includes topics on leaf arrangements, leaf types, leaf structure, leaf color, abscission, and importance to humans...
This lesson looks at population attributes, regulation, and growth. It also covers population genetics, particularly genetic variations, natural selection, genetic drift, genetic migration, and speciation...
