Eutrophication is the addition of inorganic nutrients to an aquatic system. Also artificial substances such as nitrates and phosphates, through fertilizers.
Normal lake Lake during eutrophication
The development of biomass in an ecosystem is limited, most often, by the lack of nitrogen in continental environments.
1. Soil retention
2. Runoff surface water
3. Atmospheric deposition
4. But the main cause is the increase of nutrients.
- There are three particularly troubling ecological impacts:
- Decreased biodiversity.
- Changes in species composition and dominance.
- Toxicity effects.
- Definitons, causes, and consequences from Wikipedia.
The wolf is the largest member of the canine family. Gray wolves range in color from grizzled gray or black to all-white. As the ancestor of the domestic dog, the gray wolf resembles German shepherds or malamutes.
The most common cause of death for wolves is conflict with people over livestock losses. While wolf predation on livestock is fairly uncommon, wolves that do prey on them are often killed to protect the livestock. Defenders is working with livestock owners to develop non-lethal methods to reduce the chances of a wolf attacking livestock. These methods include fencing livestock, lighting, alarm systems and removing dead or dying livestock that may attract carnivores like wolves.
Another serious threat is human encroachment into wolf territory, which leads to habitat loss for wolves and their prey species.
Overall, the greatest threat to wolves is people’s fear and misunderstanding about the species. Many fairy tales and myths tend to misrepresent wolves as villainous, dangerous creatures.
TRY TO SAVE THEM!
Darwin was doing a voyage, for his second expedition. It set sail from Plymouth Sound on 27 December 1831.
The book, also known as Darwin’s Journal of Researches,that demonstrates Darwin’s keen powers of observation, written at a time when Western Europeans were exploring and charting the whole world.Darwin’s notes made during the voyage include comments illustrating his changing views at a time when he was developing his theory of evolution by natural selection and includes some suggestions of his ideas.
Darwin Visits the Galapagos Islands
After considerable explorations in South America, the Beagle reached the Galapagos Islands in September 1835. Darwin was fascinated by such oddities as volcanic rocks and giant tortoises. He later wrote about approaching tortoises, which would retreat into their shells. The young scientist would then climb on top, and attempt to ride the large reptile when it began moving again. He recalled that it was difficult to keep his balance.
While in the Galapagos Darwin collected samples of mockingbirds, and later observed that the birds were somewhat different on each island. This made him think that the birds had a common ancestor, but had followed varying evolutionary paths once they were separated.
Darwin, H.M.S. Beagle, and the Theory of Evolution
Darwin had been exposed to some thinking about evolution before embarking aboard H.M.S. Beagle. So a popular conception that Darwin’s voyage gave him the idea of evolution is not accurate. Yet is it true that the years of travel and research focused Darwin’s mind and sharpened the powers of observation that would eventually lead to the publication ofOn the Origin of Species in 1859.
(Lo siiento profe si no esta muy bien, estoy de vacaciones y suerte que lo he podido hacer, conectandome un rato en un bar…)
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets in two nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly equal shares of these cellular components
Phases of mitosis
- Prophase: Is a stage of mitosis in which the chromatin condenses into a highly ordered structure called a chromosome in which the chromatin becomes visible.
- Metaphase: Is a stage of mitosis in the eukaryotic cell cycle in which condensed & highly coiled chromosomes, carrying genetic information, align in the middle of the cell before being separated into each of the two daughter cells.
- Anaphase: Is a stageof mitosis when chromosomes separate in an eukaryotic cell. Each chromatid moves to opposite poles of the cell, the opposite ends of the mitotic spindle, near the microtubule organizing centers. During this stage, anaphase lag could happen.
- Telophase: Is a stage a stage in both meiosis and mitosis in a eukaryotic cell. During telophase, the effects of prophase and prometaphase events are reversed. Two daughter nuclei form in the cell. The nuclear envelopes of the daughter cells are formed from the fragments of the nuclear envelope of the parent cell. As the nuclear envelope forms around each pair of chromatids, the nucleoli reappear.
Alfred Wegener Theory.
In the litosphere are the plate tectonics. These move forming different types of plates.There is a theroy which was proposed by Alfred Wegener.
Evidences for continental drift:
- Geographical: Fit of the continents
- Paleonthologycal: Identical fossils were located directly opposite on widely separated continents.
- Geological: Similar rock types on continents on opposite sides of the Atlantic Ocean.
Plate Tectonics Theory.( http://www.sci.csuhayward.edu/~lstrayer/geol2101/2101_Ch19_03.pdf )
Concepts of continental drift and seafloor spreading are united into a much more encompassing theory known as plate tectonics.
This is a far-reaching theory that has become the basis for viewing most geologic processes — mountain building, paleontology, volcanism, earthquakes, etc.
The Earth’s surface is composed of rigid plates known as the lithosphere. These plates overly a weaker region of the mantle known as the aesthenosphere.
There are 7 major plates and over a dozen smaller plates. Plates move slowly but continously on the order of a few cm/year.
Nerea López Peirona