The Pyrenean newt is a kind of salamander found in the Pyrenees of Andorra, France and Spain. Its natural habitats are temperate forests, rivers, freshwater lakes, marshes and caves.

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In the image, the “Ibón de las Ranas”, a tarn located in the Pyrenees, which is home of a community of newts, among other species.
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Adults are 10 to 15 cm long of which almost half is the tail. Their back is of an uniform dark brown colour, sometimes with yellow spots or a yellow longitudinal stripe. They have also a yellowish or orange belly. Unlike other species of non- Pyrenean newts, the adult has no crest on the back or tail. The larvae are lighter in colour, with dark spots, but they do have a crest on the tail.
The Pyrenean newt diet is compound of a wide range of insects and other aquatic invertebrates. They have an hibernation period of 8-9 months, depending on the altitude, which varies between 500 and 2500 m.

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It is an oviparous amphibian. In mating season, males belly turns orange, while females maintain their grey colour with a yellowish stripe on the middle. They reproduce by internal fecundation. The copulation happens in the water and takes several hours. The metamorphosis between larvae and adults lasts for one year. However, at high altitudes these time almost doubles.
This specie , although it is not endangered, has been rated as Nearly in Damage. Their main threat is habitat destruction, the process in which a natural ecosystem becomes unable to support the species present in it. Also, they are very vulnerable at the day because they remain still on the ground, making an easy target for predators and even for humans.
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The images are from this website.
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Today we have made an introduction for the new topic, ecology. We have designed a spider diagram by brainstorming and then the teacher had explained us the most important words, the ones we are going to study. We have talked about biotic and abiotic factors of an environment, the relations between them (simbiosis, etc), food webs and food chains, biodiversity…

Here is a complete webpage about this.

In this quite interesting video the proffesor George Wolfe explains how speciation may occur, the circunstances it needs to happen and what were Darwin theories about it.

Firstly, we should know that speciation is the evolutionary process by which new biological species arise. With that knowlegde we can assume that, as Wolfe says, the first point of speciation is an isolating event, as for example the Gallapagos Islands (the ones Darwin visited in his voyages in the Beagle) and his different species of finches. That diversity was, in that epoch, a strange occurrence because climates in the region were very similar as those in other areas. So, why had finches developed in such complex ways in the archipelago?

The answer is divided in four aspects. According to Wolfe, the most important cause of speciation is geographical isolation, which interrupts gene flow between organisms that lost their opportunity to reproduce with variated ones.

Another point is genetic divergence. As populations in isolated regions have few members, variations within them represent a high percentage of the total amount, and in consequence have more possibilities of being transmitted to new generations.

The third aspect of speciation is adaptative radiation, or cladogenesis. As organisms are living in an isolated environment they aren´t competing for resources with other species.

Here we can see that a same fly specie develops in two isolated environments until two new species evolved, which can just interbreed within their same specie.

Finally, and also the last one chronologically, there is reproductive isolation, which means that organisms in an aparted population won´t be able to reproduce when relocated in a mixed region where their ancestors live because they´ve lost their genetically similarities. From that moment, these population must be called a specie.

I´m sorry the summary of the video allows no space for questions about it as it solves all of them, so there would be no need of looking the video to answer them.

Narwhals are a kind of toothed whale characterised by their straight and long tusk (horn) that rises from the upper left jaw. Found primarily in Canadian Arctic and Greenlandic waters , the narwhal is a uniquely specialized Arctic predator. In the winter, it feeds on benthic prey, mostly flatfish, at depths of up to 1500 m under dense pack ice. Narwhal have been harvested for over a thousand years by Inuit people in Northern Canada and Greenland for their meat and the ivory of the tusk,  and a regulated subsistence hunt continues to this day. While populations appear stable, the narwhal has been deemed particularly vulnerable to climate change due to a narrow geographical range and specialized diet. However, the world population is currently estimated to be around 75,000 individuals. Apart from that, very little more is known about this rarely observed whale and there are few images of alive specimens.

Here there are their physical adaptations to the environment:

  • Lack of a dorsal fin: enables them to swim beneath ice to hide from their main predator, the killer whale. But this has an important disadvantage, that they can´t swim fastly. This is an “survival of the fittest” adaptation: narwhals that couldn´t hide below ice probably have been hunted by killer whales.
  • Very flexible neck: for scaning in a better way the deep waters of the Arctic, and so for capturing more prey. It´s an “struggle for existence” adaptation, abecause narwhals able to hunt and nourish succesfully have more chances to survive and reproduce.
  • Thick layer of blubber (whale fat): to retain heat to survive in the freezing waters of the North. It can be classified as an adaptation to the environment.
  • Higher range of echo location: to communicate through water from  further distances than normal whales.
  • Tusk: is traversed by up to 10 million nerve pathways. Scientists believe that they use it to make holes in sea ice to determine its thickness, to sense underwater pressures and temperatures and also as a special antenna to navigate by echolocation. Moreover, it´s thought to be a secondary sexual characteristic, as for example the feathers on the tail of peacocks.

This strange double toothed narwhal skull is exposed in the Zoologisches Museum, Hamburg.

narwalschaedel

  • NATURAL SELECTION:

Over-production: a narwhal´s life expectancy is around 50 years. Gestation is thought to last from 14 to 15 months and, except in very few occasions, a single calf is born.

Struggle for existence: narwhals diet is quite restricted and specific. Unlike their relative, the beluga whale, they don´t “eat what they find”. Their prey is predominantly composed of Greenland halibut (a deepwater fish), polar and Arctic cod, shrimp (kind of crustaceans), squid and octopus.

Variation: narwhals are one of the two species in the Monodontidae family, which may have evolved from the other: the beluga. They are very similar in physical appearance, but narwhals teeth structure consists just in two teeth, and one of them develops into a tusk that ranges from 2 to even 8 metres (the longest ever found).

Survival of the fittest: narwhals´upper skin has a greyish and motted pigmentation, that gives its name (narwhal means “corpse whale” in Old Norse) and that may be useful for camouflaging  in the deep waters of the Arctic.

Advantageous characteristics are passed on to offspring: narwhals able to avoid killer whales, because of their speed (they are faster, but killer whales attack them when they are unaware, knock them with a head impact and…) or their camouflage; or able to find a mate using echolocation; or capture more prey… in conclusion, being well-adapted, will have more possibilities of transmitting their genes to the next generation, and so these characteristics remain.

If you want to know more about narwhals:

A genetically modified organism (GMO) is a plant, animal or microorganism whose genetic code has been altered, subtracted, or added (either from the same species or a different species) in order to give it characteristics that it does not have naturally.

The techniques used to produce GMO’s are generally known as genetic engineering, and the main process to create GMO’s is recombinant DNA. This technique uses DNA molecules from different sources, combines them into one molecule to create a new set of genes, and transfers the new set into an organism, giving it modified or novel genes. It’s obvious that this kind of alterations are quite new, but indeed mankind has been specially breeding or crossing species in order to achieve better results for hundreds of years. Genetic engineering enables scientists to do this much faster and with more detail.


Transgenic organisms, a subset of GMOs, are organisms which have inserted DNA that originated in different species. Some GMOs contain no DNA from other species and are therefore not transgenic but cisgenic.

Examples of GMOs are highly diverse, and include animals such as mice, fish, transgenic plants (like altered bananas mixed with genes of fish to grow quickly, bigger or with more vitamins), or various microbes, such as fungi and bacteria. The generation and use of GMOs has many reasons, chief among them are their use in research that addresses fundamental or applied questions in biology or medicine, for the production of pharmaceuticals and industrial enzymes, and for direct, and often controversial, applications aimed at improving human health (gene therapy) or agriculture (golden rice).


Here is a video of the battle between GMOs and organic food. It is not linked with an explanation of GMOs bus it is funny and we like it.

http://www.youtube.com/watch?v=MfTQergr29M

  • Advantages and disadvantages of GMOs:

Advantages:

  • Fewer pesticides are needed to be used due to insect pest resistant plants.
  • Decrease in costs of growing and farming, due to the reduced use of pesticides.
  • Higher crop yields.
  • Less deforestation needed to feed the worlds growing population.
  • Decrease in food prices due to lower costs and higher yield. As people in poor countries spend over half of their income on food alone, lower food prices mean an automatic reduction of poverty.
  • More nutritious products.
  • Strict and very complete standards that GMOs have to full achieve.
  • Creation of “super foods” due to better knowledge. Super foods are types of food that are cheap to produce, grow fast in large quantities, highly nutritious.
  • New products. For examples, scientist identified the gene responsible for caffeine in coffee beans; by excluding this gene, decaffeinated coffee beans can be grown naturally.
  • Reduction of sicknesses and illnesses, as GMO crops are more nutritious. Vitamins and minerals can be provided to children and to people, where they were inaccessible before.
  • Developments of new kinds of crops that can be grown at extreme climates, for example, dry or freezing environments (like deserts). For example, scientist developed a type of tomato that grows in salty soil.

Disadvantages:

  • Harm to other organisms. For example genes and their effect included in a crop may turn out to be poisonous to insects.
  • Cross-pollination with traditional, organic plants. Cross pollination can occur at quite large distances. New genes may also be included in the offspring of the traditional, organic crops miles away. This makes it difficult to distinguish which crop field is organic, and which is not, posing a problem to the proper labelling of non-GMO food products.
  • Spread of new, more resistant “superweeds” and “superpests”.
  • Major trading countries that obtain most of the benefit from the production and trade of genetically modified crops. This might cause more geopolitical conflicts.
  • Although it is not proved, GMOs may cause health problems.
  • Possible damages to the environment.
  • Variations in tests and safety standards around the world that led to uncontrollable crops.
  • Unforeseen risks and dangers due to the complexity of nature.
  • Allergies may become more intense, and also, new allergy types may develop.

Links:

http://www.gmo-compass.org/eng/home/

http://www.gmo-safety.eu/en/

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml

Work by  David, Iratxe, Perseo, Rubén and Santi.

Just a more complex and scientific way of extracting DNA, this time from cheek cells. I´m sorry the blog doesn´t recognise *.swf, so here is the link.

Have a nice holidays!

Vandana Shiva is a very important figure in the defense of the Environment. This Indian woman is an ecologic activist, philosopher, ecofeminist, writer and winner of the Peace Alternative Nobel Prize in 1993.

She was born in Dehra Dun (India), in 1952. During the 1970s Vandana participated in the Chipko Andolan, an ecological movement that was the first to use the method of hugging trees for preventing their cutting. She has also campaigned against genetic engineering and is specialized in biodiversity, biotechnology and bioethics. Until now she has achieved to publish more than 300 essays and 13 books, as “Stolen Harvest” or the most recent one, “Soil Not Oil”. This pacifist woman is a declared follower of Gandhi and supports non-violent activism.

Actually, she is the leader of the International Globalization Forum and directress of the Investigation Foundation of the University of Oslo.


Vandana Shiva es una figura muy importante en la defensa del Medio Ambiente. Esta mujer india es una activista ecológica, filósofa, eco feminista, escritora y ganadora del Nobel Alternativo de la Paz en 1993.

Nació en Dehra Dun (India), en 1952. En los años 70, Vandana participó en el Chipko Andolan, un movimiento ecológico que fue pionero en el método de abrazar a los árboles para protegerlos de la tala. Además, ha hecho campaña contra la ingeniería genética, y está especializada en biodiversidad, biotecnología y bioética. Hasta el momento, ha publicado más de 20 ensayos, como “Cosecha robada”, o el más reciente, “El suelo no es petróleo”. Esta mujer pacifista es una seguidora declarada de Gandhi y apoya el activismo sin violencia.

Actualmente, es la líder del Foro Internacional de la Globalización y directora de la Fundación de Investigación de la Universidad de Oslo.