hard

Thermoregulation

...c " animals. But it must be remembered there is no hard and fast line between the two groups. Also, from w...lated well, high temperature in feet and hooves is hard to maintain. Hibernation estivation and daily torpor Rather than cope with limited food resour...

Skin

...he skin provides. On some animals the skin is very hard and thick, and can be processed to create leather . Damaged skin will try to heal by forming scar tissue , often giving rise to discoloration and depigmentation of the skin. The skin is often known as "the largest organ in the human body": this a...

Skeleton

... arthropods and shellfish : the skeleton forms a hard shell -like covering protecting the internal organs. The phyla arthropoda and mollusca both have exoskeletons. Since exoskeletons necessarily limit growth, phyla with exoskeletons have come up with various solutions. Most molluscs have calca...

Signal transduction

...ic effects. Hormones signalling is elaborate and hard to dissect. A cell can have several different receptors that recognize the same hormone, but activate different signal transduction pathways; or different hormones and their receptors can invoke the same biochemical pathway. Different tissue types ca...

Nutrition

...or the high stresses on their body. People working hard in a cold environment may need high fat levels in their diets, to help maintain normal body temperature. This beneficial high fat level may be very harmful for people in other situations, eg a sedentary worker in an air-conditioned office. So the a...

Keratin

...ft epithelial keratins or cytokeratins and the hard hair keratins . These can be divided into type I (acidic) and type II (basic to neutral) subfamilies. Keratin is also what fungi that infect us (such as Athlete's Foot and Ringworm ) feed on. Keratin is also a part of certain structures that g...

Immune system

...ms are common, so it not always possible to draw a hard and fast boundary between the individual components involved in each, despite the clear difference in operation. Higher vertebrates and all mammals have both an innate and an adaptive immune system. Innate immune system The adaptive immune s...

Fitness landscape

...to determine the quality of a single solution, but hard to go through all possible solutions one by one (it is easy to determine the driving time for a particular route of the delivery truck, but it is almost impossible to check all possible routes once the number of destinations grows to more than a hand...

Evolution

...ation is an uncommon occurrence, usually requiring hard parts (like bone) and death near a site where sed...e is sparse before the evolution of organisms with hard body parts, such as shell, bone, and teeth, but exists in the form of ancient microfossils and the f...

Ebola

...of the Congo 12 . Other countries that have been hard hit include Uganda, where an outbreak in 2000 stifled its waning tourism industry (Busharizi). Ebola has also made countries like Uganda, Democratic Republic of the Congo, and Sudan to lose revenue through the loss of people who would have been able ...

Drosophila

...nted animals with paired, jointed appendages and a hard exoskeleton made of chitin . They have an open circulatory system with a dorsal heart, hemocoel occupies most of the body cavity, and coelom is reduced. The insect respires by means of air-filled internal tubes, the tracheae . This ectoderm...

Charles Darwin

...mporaries, these elements of his thought are often hard for modern readers to reconcile with his overall scientific approach. Darwin was contradictory and ambiguous in his views on the ways in which his theories included particular social implications. He certainly agreed with views first expressed (and...

Brain

...sheep . He concluded that since the cerebellum was hard to the touch, it must control the muscles, while since the cerebrum was soft, it must be where the senses were processed. Galen further theorized that the brain functioned by movement of fluids through the ventricles (Bear, 2001). In the Age of Rea...

Bone

...inks General overview It is a relatively hard and light- weight composite material , formed mostly of calcium phosphate (in the chemical arrangement termed calcium hydroxyapatite), which has relatively high compressive strength though poor tensile strength . While bone is essentially britt...

Antibiotic

...tation . People in developed countries now find it hard to imagine that a simple scratch once always carried the risk of infection and death. See also Timeline of antibiotics . Classes There are many way to classify antibiotics. One such classification is by chemical structure: Aminoglycosi...