... developed. As fossilization is an uncommon occurrence, usually requiring hard
parts (like bone) and death near a site where sediments are being ... evidence of early life is sparse before the evolution of organisms with hard
body parts, such as shell, bone, and teeth, but exists in the form of ...
... " and " poikilothermic " animals. But it must be remembered there is no hard
and fast line between the two groups. Also, from work done by J. O. ... extremities are not insulated well, high temperature in feet and hooves is hard
Hibernation estivation and daily torpor
Rather than ...
... medicine . It has been said that this is the greatest advance in health since modern sanitation . 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 .
4 Bone matrix
5 Bone development
7 See also
8 External links
It is a relatively hard
and light- weight composite material , formed mostly of calcium phosphate (in the chemical arrangement termed calcium hydroxyapatite), which has ...
... (Bear, 2001).
During the Roman Empire , the anatomist Galen dissected the brains of 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 ...
... a jab at the Irish), and though he was not so sexist, racist, or classist as many of his contemporaries, 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 ...
... and female fruit flies.
Drosophila is part of the phylum Arthropoda , a phylum of segmented 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 ...
... affected tourism in the countries where it is present, especially in the Democratic Republic 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 ...
... Evolutionary optimization techniques are particularly useful in situations in which it is easy 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 ...
... an adaptive immunity also possess an innate immunity and many of the mechanisms between the systems 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 ...
... twisted beta sheet structure.
In humans, the keratin family of proteins is divided into the soft 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 ...
... Athletes may need high levels of protein and energy to enable high performance and repair for 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 ...
... may be of one type or several, as in the case of insulin , which triggers diverse and systemic 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 ...
... such as the vertebrates , have internal skeletal systems. Examples of exoskeletons are found in 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 ...
... which in sufficient density is called fur . The hair mainly serves to augment the insulation the 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 ...