GKN Student Blogs

                      Odd Animals

The Galapagos Marine iguana is a very odd animal that evolved due to the isolation of the Galapagos Islands.

The Marine iguanas that live in the Galapagos Islands have flatten tails to help them swim. They only live on the Galapagos islands, and  eat the algae off the rocks in the shallow water. They live in large colonies on the shores. They were discovered by Charles Darwin, when he sail to the Galapagos Islands on the HMS Beagle.

When the first iguanas arrived on the Galapagos by the ocean current, they ate the food on land, but as the food on the land began to disappear, they started to go to the shore to find a meal. Eventually, they began going into the water for food and they kept going deeper and farther from shore. Now that they ate in the sea, they needed to swim in order to get food, so eventually they evolved flatted tails. This is what created the first marine iguana. There are no other iguanas in the known world that swim.

One species that is going through a similar change are orangutans. To be more specific, a group of orangutans on an island. They are a part of a rescue plan to help save orangutans from extinction. Normally, orangutans are nomads and live alone, but these orangutans live together in a community.

They could just spread out and be alone, like they would be in the wild, but they choose to stay together in groups. This is a very strange thing for orangutans to do. They also share food with each other sometimes. All of these things would normally not happen in the wild. With more habitat destruction, wild orangutans might begin to make communities, like the orangutans on the island did.

When a barrier, which can be objects such as a stretch of water or a mountain range, separates different groups of the same species, the groups may no longer be able in breed with one another. Because of this they may form their own species. They will adapt to the climate and habitat of the new environment. An example of this is the Pup Fish that lives in Death Valley.
About 50,000 years ago Death Valley had a damp, rainy environment that had many lakes and ponds that were connected by rivers and streams. Over several thousand years the rainfall in the region began to decrease. This caused the rivers and streams to dry up so the lakes and ponds were no longer interconnected. And because of this, different groups of Pup Fish became isolated in their own pond. Because each pond had a slightly different environment, the different groups of pup fish had to adapt to their new surroundings. This happened about 4,000 years ago. Now Death Valley is a desert with an occasional pond which contains a different species of pup fish. Scientist know that they are different species because if the fish breed they will not produce fertile offspring. Now there are many different kinds of Pup Fish that can’t interbreed, they can only breed with the other fish in their pond. The different kinds of Pup Fish are now evolving independently.

Many people know about the speciation of the Galapagos Tortoises, but I bet you didn’t know about the new species of mosquito living in the Tubes in London. These mosquitoes used to drink the blood of birds before they moved underground about 100 years ago, but now, because of their geographic isolation in their subterranean climate they have evolved to take advantage of the new food sources available. The original species was named Culex pipiens and the new species is called Molestus. Over the last hundred years, Molestus have evolved their menu to include rats, mice and maintenance workers. The mosquitoes preyed on people hiding during World War II. Researchers from Queen Mary and Westfield College found that Culex pipiens cannot mate with Molestus, thus proving that Molestus is the result of allopatric speciation. Mosquitoes reproduce very fast, especially in underground places like the Tubes. It took a mere century for this new species to be created instead of the thousand years it would have taken another, slower reproducing, species.

http://www.gene.ch/gentech/1998/Jul-Sep/msg00188.html

One of the ways that 2 atoms can to form compound is through a covalent bond. First, two atoms get drawn together. They are only connected by a tiny strip of each atom that is held together by electrons. You may think that the bond is weak, but it is very strong. And if two atoms that are the same are near each other they will bond. The air is made up of 20% oxygen. Most of the oxygen in the air is more than one atom.

Elements join together in a covalent bond to form molecules by sharing electrons. Covalent bonds help atoms to get all the electrons that they need to fill up their valence shells. Electrons involved in a non polar covalent bond do not belong to one atom or the other. If they are electronegatively equal, the electrons belong to both. They also spend the same amount of time around one atom as they do on the other so this makes the molecule non polar.

Electronegativity determines whether an atom will pull electrons toward itself. When atoms with different levels of electronegativity join together to form a covalent bond, the molecule becomes polar. The atom with the larger electronegative charge will become negative, and the weaker atom will become positive. The periodic table organizes elements by electronegativity from west to east, from south to north.

Elements bond because of their similar chemical properties. These properties are determined by their electron configuration. Elements are organized vertically in the periodic table by their electron configuration. 

http://voicethread.com/share/219278

A stable atom is when an atom has a full shell of electrons. This means there are the maximum number of electrons that can possibly be in that shell. For most atoms this number is 8. If an atom does not have a full shell of electrons it will seek out other atoms that have the necessary amount of electrons needed by the atom. When an atom finds another atom that fits its needs it will try and share an electron in order to complete its shell. The sharing of electrons can only happen with the outer shell. This means the shared electron spend time with both of the atoms. When this sharing of electrons happens, it is called a covalent bond. This bond is the strongest of the bonds.

There are different types of covalent bonds, such as single covalent bonds in which the atoms share only one electrons, double covalent bonds in which the atoms share two electrons and this pattern continues until you reach the number 6. Some scientist think that atoms cannot share any more electrons.

The reason that some atoms cannot make an covalent bond is because certain criteria need to be met before the bond can happen. Some of these criteria are: neither atom can have a full shell, they must need a similar amount of electrons and they need to have a similar electrical charge. For example, an Argon atom cannot bond with any other atom because an Argon atom has a full shell, so it cannot share electrons.