Cities are growing massively, and three main problems caused by this expansion are the increasing number in population, the wasted time in traffic jams and long displacements and the pollution, noise and accidents due to the big amount of private vehicles.

This is why in some towns and cities in Europe, like ours here in Zaragoza, people have protested and proposed some changes in the public transport services and the private uses of vehicles in the streets.

Some measures carried out by the city council are the so called ‘Ecobuses’ which work with biodiesel (a respectful fuel with the environment made with renewable raw materials such as vegetal oils or animal fats).

Another solution to the problems above and for short displacements the use of bicycles or just walking around the streets (for which the sidewalks of the streets have been extended).

Bicycles are a perfect mean of transport for cities like this, they are cheap, respectful with the environment and easy to use and transport. These are the main reasons why the city council has started up the expansion of tracks for bicycles around and in the center of the town.

In order to promote the use of bicycles, a new system of circulation by means of payment bicycles has begun (Bizi). These bicycles are available by a reasonable price and just by getting a “bike card” you can use any of the bicycled disposed around the town during half an hour.

sources: http://www.bizizaragoza.com/

pictures: http://4.bp.blogspot.com/_Bylnku30ukw/R6XUBq1Kn3I/AAAAAAAAAUo/2iv49CHqJhg/s400/Zaragoza%2B2007%2B194.jpg , http://www.zgzhoy.es/wp-content/uploads/2009/08/2545563595_ebf86f7973.jpg , http://upload.wikimedia.org/wikipedia/commons/5/51/Tuz_Ecobus.jpg

Hi there,  this is a video about wels catfish hunting pigeons at Ebro river. I know the quality isn’t very good, but this is a clear example of how this fish hunt the birds.

For more information click here (source: wikipedia)

Here I post a link with a webpage about ecology which gives a good help with the topic.

I also recommend this search engine named Ecosia . For more information, watch this video about the webpage.

In the following video, professor George Wolfe explains us what homologous structures are. He starts by mentioning Vestigial organs (organs in our bodies that have no aparent funtcion), an after that, he begins with what we know as homologous structures. These are structures in animal bodies that may look different in several species(e.g. legs in cats and arms in humans), but in fact, they are composed by the same physical structure.

This example is clearly seen with the structure of a human arm and a dolphin flipper. They both have  one bone at the beginning of the arm (humerus), followed by two other bones (radius and ulna), a wisrt and the five fingers.

Homologous structures may have different function, but will definitively have the same structure. And as we know, homologous structures are determined by our genes.

After this, the man in the video explains analogous structures or convergent evolution. This means that different animals with an aparent same adaptation (e.g. birds with wings and moths with wings aswel) may have evolved from completely different ancestors, and in order to determine this, we need to look at the DNA of both examples, not just stay on the surface.

At the end of the video, the man shows us that when we are embryos, we have a lot more homology than when are adults. We can compair embryos  from different species (reptile, human, pig and bird) and we can perfectly see the homologous organs and structures they have in common (e.g. tail and gills), what leads us to think that we all come from a similar origin (divergent evolution).

Sources: (pictures: http://www.sciencewithmrmilstid.com/media/comparativestructure.jpg http://www.peabody.yale.edu/exhibits/treeoflife/images/convergence4.jpg http://www.carolguze.com/images/embryos/comp_embryosHaeckel.ipg.jpg) (links: http://en.wikipedia.org/wiki/Vestigiality , http://en.wikipedia.org/wiki/Convergent_evolution , http://en.wikipedia.org/wiki/Divergent_evolution)

Star-nosed moles are a particular type of moles easily identified by the eleven pairs of  fleshy appendages sorrounding their nose.

Star-nosed moles live most of their time underground, and as there is not much light down there, their sense of view is not as developed as the rest of senses. In return, they have developed an enormously sensitive sense of touch, leading to this appendages around their nose. Star-nosed moles live in wet lands where the earth is soft and they can dig easily with their hard and rough claws at the end of their legs. As they live mainly thanks to their sense of smell, their ears are not very usefull and have almost disappeared.

The incredibly sensitive nasal tentacles are covered with minute touch receptors known as Eimer’s organs. The nose is approximately one centimeter in diameter with approximately 25,000 Eimer’s organs distributed on 22 appendages.Recent reports give this animal the title of fastest-eating mmamal,  taking as short as 120 milliseconds to identify and consume individual food items. Its brain decides in the ultra short time of 8 ms if a prey is comestible or not. This speed is at the limit of the speed of neurons.

Star-nosed moles are really good swimmers and they also possess the ability to smell underwater. It is done by exhaling air bubbles onto objects or scent trails and then inhaling the bubbles to carry scents back through the nose.

Well, deducing that starting from a ancestral mole, an (or some) individual may have had a significant variation (due to sexual reproduction or a mutation), these new mole may have evolved into what we now know as the star-nosed mole, giving these an advantage when hunting by making a 3d picture of the surroundings (as shown on the videos below). Everything is well explained in this videos, for example, the advantage of the star-nosed with their tiny size and advanced nose. We deduce that with this advantages, the first star-nosed moles began to survive in this “survival of the fittest” in the wetlands, where they lived. These first star-nosed were able to hunt and eat much more (underground) than bigger animals in the surface.

Video in english:

Video in spanish: visit this page

(Source: wikipedia: http://en.wikipedia.org/wiki/Star-nosed_Mole)

I am sorry for the delay, but, after a whole weekend with no internet at home, my connection has finnaly returned, so I can post last week summary.

Tuesday 16th of February.

At the beginning of the class, Fernando, as usual, asked if there was any problem with the homework. After that, he spoke about non-mendelian genetics, focusing on co-dominance and incomplete dominance. Thanks to the help of the whiteboard, the teacher explained co-dominance ( by Wikipedia: “Co-dominance occurs when both alleles contribute to the phenotype.”) and incomplete dominance (inheritance in which one allele is not completely dominant over the other one) in flowers, with the example of roses. As incomplete dominance shows, an offspring of red (homozygous) and white (homozygous) parents will be heterozygous and its phenotype will be pink and as we can learn from co-dominance, this offspring will be red with white spots or white with red spots :

Traits Red White
Alleles R W
Co-dominance Red

RR

Red and white with spots

RW

White

WW

Incomplete dominance Red

RR

Pink

RW

White

WW

After this little bit of theory, we corrected some homework from previous days and continued with the photocopy with genetics exercises.

Thursday 18th of February.

In this lesson, Fernando talked about human blood types explaining that human blood is determined by co-dominant alleles, and that there are three different alleles for our blood types( IA, IB, i) with this possible genotypes:

Genotype Blood Type
AA  (IA IA )

AO  (IA i )

A
BB  (IB IB)

BO  (IB i)

B
AB  (IA IB) AB
OO  ( i i) O

Alleles ‘IA and ‘IBare co-dominant between them, but ‘i’ is recessive to both of them.

When we had learned this previous information, Fernando made us guess (in an exercise) his parents genotypes just by giving us his and his brother’s phenotype.

Friday 19th of February.

After correcting some exercises from previous activites about human blood types, Fernando explained us how human sex inheritance works (or a part of it).

Women’s haploid cells contain 23 chromosomes (22 plus the chromose X) and men’s contain 22 plus the X or Y chromosome. When an X sperm cell enters in a X egg cell, the possible result is going to be always a girl (XX). When an Y sperm cells enters a X egg cell, the results are shown in this table below.

X X
X XX XX
Y XY XY

After learning this information, we spent the rest of the class doing exercises with the help of the teacher about human diseases (such as colorblindness or hemophilia) passed through sexual inheritance.

As Fernando wanted us to post web pages that we usually visit, here I let you this link where you can find a web page about science.

Thank you for worrying so much, i’m glad (^^). I think the problems may have ocurred when copying the text from the text processor (just 1 out of 3 tables copied correctly, and I think some sentences were missed in between). Sorry about the spelling problems, and, by the way, I checked in this page that the pronunciation of homozygous and heterozygous is different depending on the way you speak (English or American).

Hi guys. I know the video and picture have nothing to do with the subject,  so onelove 😉