Notes, abstracts, papers, exams and problems of Biology

5. Internal activity hazard
5.1. Seismic hazard
Earthquakes develop mainly in plate boundaries
Constructive and passive boundaries are usually under the sea
level, thus they have a minimum seismic hazard degree. However,
they may produce tidal waves (tsunamis).
Destructive boundaries develop many powerful earthquakes, and at
the same time, it occurs in usually highly populated areas. Thats
why that zones have the highest seismic hazard (fire belt)
5.2. Volcanic hazard
The volcanic hazard depends on the magma viscosity (which, in turn,
depends on the amount of silica) and on the gas content.
The volcanic activity in hot spots and constructive boundaries is

2.2. Internal processes
The internal processes are those directly or indirectly caused by the Earths
internal heat:
„h Metamorphism
„h Magmatism
„h Isostasy (epirogenic movements)
„h Orogenesis (orogenic movements)
2.2.1. Magmatism and plate tectonics
Rock melting can be produced by the following processes
o A raise in the rock temperature
o A drop in the confining pressure
o The presence of fluids (water)
According to plate tectonics, three igneous environments exist:
o Continental rifts, mid-ocean ridges: Mantle rocks melt by a drop in
pressure

1.1. Types of stress
Stress is a force applied over an area. It can be classified into:
Confining stress (stress is equal from all directions)
Differential stress (stress is not equal from all directions)
Compressional stress, produced by opposite, convergent forces
Tensional stress, produced by opposite, divergent forces
Shear stress, produced by opposite, parallel forces

As the stress is applied on a rock it begins to deform or to strain. A strain

Então são originadas as espermátides haplóides que passam por um processo diferenciação, a espermatogênese (forma-se um longo flagelo)
Ovogênese: ocorre no interior dos ovários, ao contrario da espermatogênese, ela inicia-se na vida intra-urinaria. Os ovócitos passam por um processo de dormência ate a puberdade. Ao atingir a maturação, o folículo ovariano é denominado de folículo de graaf. O óvulo é expelido pelo ovário configurando o que chamamos de ovulação.
Fecundação: Ocorre na tuba uterina e compreende a fusão dos núcleos do gameta masculino com um feminino, dando origem a célula ovo ou zigoto. Após, o zigoto origina um pequeno embrião que percorre a tuba uterina e se instala no endométrio.
Controle hormonal masculino: Hormônio folículo estimulante (FSH) promove a maturação dos espermatozóides nos tubos seminíferos. Hormônio estimulante das células intersticiais: estimula a produção de testosterona. A testosterona é responsável pelas características sexuais masculinas (crescimento de barba e mudança de voz).

I get up at 7 a.m. I have a shower
then I go to the school in the school I have many friends
, with my friends I usually go to the cinema
I go shopping I go to the disco and I am happy                                                                                                                               al the time,but in the school I don´t speak I only study,in the                                                                                                                                                                         evening in my house I  do homework and go out little time