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Fishes in Ribeira de Carvalhais |
In Ribeira de Carvalhais it is possible to find various plants and animals such as birds, amphibians and fish. This is the case of the escalo (Squalius carolitertii), an autochthonous species of the Iberian Peninsula that lives in Ribeira de Carvalhais. All the existing animals and plants help us to evaluate the state of health of this aquatic ecosystem. Thus, whenever we find a remarkable biodiversity that includes species susceptible to disturbances (like water pollution, for example), we can say that we are in the presence of aquatic and coastal ecosystems with high ecological quality and environmental health that must be preserved. |
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Life in Ribeira de Carvalhais |
In Ribeira de Carvalhais it is possible to observe a great diversity of plants and algae. In this region it is also possible to observe a great variety of macroinvertebrates, that is organisms without internal skeleton, with size superior to 0.5 mm. Examples are aquatic insects, annelids, mollusks and crustaceans. |
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Bare Rock |
Once on the surface, the rocks begin to undergo changes that lead to their degradation and the formation of the soil. At first the rock does not have any type of vegetation. In the image it is possible to observe an outcrop of the rock - bare rock.
After rising, the rock will suffer the action of physical-chemical and biological factors that will gradually change it. The bare rock is very adverse to the settlement of living beings due to sun exposure, the absence of soil and the rapid evaporation of rainwater. |
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Pioneer Species |
Lichens (association between algae and fungi) produce acids that degrade rocks and help in the soil formation, which facilitates the colonization of mosses and herbs. They are pioneer species, that is, they are the first organisms to colonize an environment where life had never occurred before. They are very simple living beings, not demanding and that endure the lack of water, of soil and high thermic amplitudes.
The group of pioneering species that settle in an arid place constitutes a pioneering community. They enrich the environment with organic materials, consolidate the soil with the roots and create some areas of shade. There emerge also small invertebrates, resistant and little demanding concerning resources |
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Climax Community |
If the conditions of the environment and the interactions do not change, the community reaches a state of climax which can last in time, and there may be species replacement. The ecosystem, although at its maximum development, is in continuous change, working in dynamic balance.
Climax Community: more stable community with a strong interaction between all animals and plants where the flows of matter and energy reach balance, settling a climax community. |
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Facade of the Romeu Church |
The population decided to make an intervention towards the preservation of the architectural heritage. The bells of the main church need to be repaired and, for this, we need to know the height of the main facade for proper crane placement.
To calculate the height of the main facade we will use two different techniques of mathematics. For the first technique we will use the similarity of triangles. Therefore we need a cross staff and tape measure.
For the second technique the concepts of trigonometry will be used. For this technique we will use a quadrant and a tape measure. |
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A student’s drawing with schematics |
In this picture it is possible to observe the calculation made by a student resorting to the similarity of triangles. Thus, using the adapted cross staff in the visual field that allows to see the top of the facade and, being the cross piece at the level of the eye, parallel to the ground, and the staff hit with the top of the belfry it is possible to see that the cross piece has a value of 7 cm and the height between the cross piece and the end of the staff is 8.3 cm. In this way, by the Tales Theorem we have that x = 11,857 m. |
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Usage of the cross staff |
The cross staff is a nautical instrument that was used to measure the altitude of the celestial bodies. The cross staff is made up of two square section rods placed perpendicularly. |
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Usage of the Quadrant |
The Quadrant is a nautical instrument used to measure the altitude of the celestial bodies. This device is constructed in the form of a quarter circle, normally made of wood or metal with degree graduations that are marked from 0º to 90º, and a plumb-bob.
In this example of field class the quadrant served to measure the height of the church facade. After placing the quadrant in a visual angle that allows to see the top of the facade, the angle of vision was identified. |
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Examples of fractures |
The entire Romeu area is occupied by heavily fissured Muscovite granite blocks. It is a light-colored granite dominated by felsic minerals, mainly muscovite and potassic feldspars.
The roots of the plants introduce themselves in the fissures / fractures of the granite block accelerating its weathering. This way they accelerate the physical and chemical weathering of the rock.
The fractures allow the penetration and circulation of fluids, accelerating the chemical reactions caused by water, leading to a modification of the mineralogical composition of the granite. |