scasimir's blog

Natural selection favors individual birds that achieve the greatest lifetime reproductive success. Finding a prime mate is the first and critical step toward success. Different investments into annual reproductive efforts then add to the diverse life histories of birds. Some birds lay many eggs, whereas, others lay just one. Also, some birds typically live for decades and others for just two or three years. To maximize their contributions to the next generation, individual birds must achieve optimal combinations of variables that affect their lifetime reproduction output.

Birds have a different style of migrating and they also use different things to help them travel long distances. First, they use visual landmarks such as highways, railways, and rivers to help them migrate even if the routes are not direct. For example, some waterfowl follow watercourses to help them migrate but often they are scared to cross open bodies water unless it’s windy. Birds also use the sun and the stars as compasses. For a long time, scientists were curious that birds traveled by the sun but, they did not know how they do it. Common starlings and homing pigeons follow the sun to lead them home and will not travel until they can see the sun. On the other hand, land birds and waterfowl maintain their directions at night by using the stars as their source of direction. Baby Indigo cannot navigate without seeing the stars when it’s their first time flying. In order for them to fly, they need to see the stars regularly during their first month in order for them to see their migratory paths.

Baby Indigo cannot navigate without seeing the stars when it's their first time flying. They need to see the sky on a regular basis during their first month in order to see and choose their migratory direction. The axis of rotation of the night sky establishes their north-south frame of reference. They learn the constellations associated with the axis. If the axis is switched, baby Indigo buntings follow the brightest star to navigate even if this migratory paths take longer to get to their final destination.

Land birds and waterfowl maintain their directions at night by using the stars as their source of direction. Ornithologists also believe that birds use a geomagnetic map which is a map of horizontal space justs as gravity and barometric pressures and it gives information about vertical space. They also believe that birds use the Earth's magnetic field to orient them. 

Birds use visual landmarks to help them travel and migrate long distances. Pigeons, for example, use railways, highways, and rivers even if routes are not direct. Some waterfowl follow watercourses to help them migrate but often they are scared to cross open bodies of water unless it is windy. They also use the sun as a compass. Homing pigeons and common starlings follow the sun to lead them home and will not travel until they can see the sun.

In classifying birds, Thomas Huxley had the idea of arranging the bones of the avian bony plate, a skeletal partition between the nasal cavities and the mouth to assemble a grouping. Since Huxley set a foundation, scientists started adding more detailed characteristics such as muscles, vocalization, and toes to the group of birds but in more specific details. After the characteristics are grouped properly, birds can be present in different orders. Orders can be branch out from common ancestors with unique characters that are easy to distinguish from the rest. Songbirds, member of Passeriformes have unique morphological traits. The more complex traits are, there is a better chance that the species won’t be related. As years go by, technology makes it clearer and easier to find similarities and differences among species because not only the physical anatomy and morphologies but also DNA sequencing plays a big role in birds classification.

When comparing DNA sequence of species, scientists understand better the evolutionary relationships that they could not find simply by looking at morphology. Evidence of DNA is changing and taxonomy is helping them fix the classification of species evolving from common ancestor. Ever since Charles Sibley introduced the DNA-DNA hybridization, DNA efficiency becomes more accurate for classification. He took a egg white protein to analyze its enzyme using this technique. Today, this technique is used by numbers of scientists to improve the use of taxonomy.

DNA-DNA hybridization is a method used to estimate the amount of genetic changes that took place in the genome as a whole since the time at which two groups diverged from their most closest ancestor. The 4 nucleotides has 4 unique base A, C, G, and T, these base pairs would allow scientists to analyze how similar each species are to one another. Fred Sheldon was one of the pioneers to perform this experiment and he confirmed that Great Blue Heron is similar to Great Egret than American Bittern.

Specific traits are based on evolutionary history called characters shared as common ancestors. In classifying birds, Thomas Huxley had the idea of arranging the bones of the avian bony plate, a skeletal partition between the nasal cavities and the mouth to assemble a grouping. Since Huxley set a foundation, scientists started adding more detailed characteristics such as muscles, vocalization, and toes to the group of birds but in more specific details.

After the characteristics are grouped properly, birds can be present in different orders. Orders can be branch out from common ancestors with unique characters that are easy to distinguish from the rest. Songbirds, member of Passeriformes have unique morphological traits. The more complex traits are, there is a better chance that the species won’t be related. Foot structure of birds is one of many examples that prove how species are related. As years go by, technology makes it clearer and easier to find similarities and differences among species because not only the physical anatomy and morphologies but also DNA sequencing plays a big role in birds classification.

One thing that I noticed was that the background and the sizes were different in both the original and the replicate. The first picture (replicate) shows that there is snow on the ground compared to the original and there are also more birds in the original picture than the replicate. The first picture from the original also shows that there are eight geese, but in the replicate there are only two and a tree trunk. On the second picture, the two differences were that, one picture was taken on land/grass (original), and the other one was taken in the water (replicate). There are only one female and a male duck from the original versus the replicate which consists of eight male and two female ducks.