scasimir's blog

The main genetic difference between humans and chimps is that humans have 23 pairs of chromosomes whereas chimps have 24 pairs of chromosomes in their genomes. Two ancestral chromosome pairs fuse at their telomeres to form human chromosome 2 during evolution. Humans and chimps are two species that are very closely related to each other. Humans and chimps have 1.2% of non-coding DNA difference in their genomes that are responsible for all the unmatching characteristics of humans and chimps.The human genome contains 46 chromosomes while chimp genome contains 48 chromosomes. The main genetic difference between humans and chimps is the number of chromosomes.

Figure 1. Penguins developed behaviors that are learned through observations and practices. They also learn how to be very vocal and social animals within their colonies. Available at https://farm5.staticflickr.com/4014/4696423445_4705431d8f_z_d.jpg by Ron Hopkins.

Speciation is the second most important evolutionary process in birds that is responsible for evolution. It is more common in Aves classes (all birds) mainly because they can geographically isolated from their original population due to migration. Allopatry causes isolation, which can occur under certain conditions. Allopatry can cause species to migrate from one place to the other and it prevents gene flow between species. Since species are migrating there is no genetic interchange between them. Various geographic changes can cause species to isolate such as movement of continents, glaciers, formation of mountains and islands. Human activity such as agriculture and deforestation can also cause species to isolate.

Most species of birds evolved in isolation called allopatry under certain conditions. Isolated islands of habitats on continents set a similar stage for speciation of bird populations that they occupy. Sister populations that were separated and isolated geographically space diverge from each other. Divergence can either be slow or rapid. Conspicuous patterns of geographical variations are the result of divergence and it can also be random which follow adaptation to different habitats and can results from sexual selection.

There are three main evolutionary processes that are responsible for evolution. The first one is phyletic evolution, which refers to a gradual change of lineages and relates one specie to another. The second one is speciation, the separation of phyletic lineage into multiple ones. Lastly extinction, the end of a lineage. However, extinction erased relationships among related species because species need other species to connect with otherwise it cannot happen if there is no species left. Species are the fundamental units for classification. There are numerous number of birds species due to different shape, color, habitat, songs and niches. Species are refer to how a single organism can reproduce and creates one or more offspring.

 

The article that I read had an abstract section that gives the reader a little background information on what it is about. The main point of the article was to figure out how urban birds tend to produce smaller and lighter offspring than rural birds. The introduction section talks about how human populations are growing and migrate to urban areas and how this change is having an impact on urban birds. I learn that “in general, life-history theory predicts that adult birds under threat of predation will reduce offspring feeding rates and consequently have reduced nestling growth rates”. I was surprised to find out that urban birds tend to reproduce less because of fear of predation, why not rural birds? because rural birds would have a greater chance of eating by their preys than urban birds.

Birds are bipedal vertebrates that evolved from theropod dinosaurs or reptiles. They are from a new class of vertebrates known as Aves which includes all birds. They have feathers and wings. The main function of their feathers is to maintain body temperature and their wings are used for flight. To maintain balance, birds placed their body in the center of the earth so it can be over and between their feet. When landing, they come closer to the ground and slowly rises to minimize the impact. 

Most birds are arboreal, in other words, tree-dwelling species. They grip on tree branches to keep their body upright and to prevent them from falling. Birds do not have claws, but instead, they have 3 digits or toes that they used to climb up trees. They also don't have teeth but instead, they have gizzards that help them digest hard nuts shell, seeds, and insects. Birds are the only species of its kind to reproduce externally. Most birds provide parental care until the eggs hatch after that the babies are on their own. They use their acute senses to help them navigate and communicate, also, they can hear sounds and see a wide range of colors more than humans. Their brain is about six to eleven time larger than reptiles and has lateralization that resembles primate brain.

Birds are very interesting vertebrates, they have feathers and wings that allow them to fly. They are bipedal vertebrates meaning they have 2 legs just like us humans. Some of them eat insects and others eat seeds. Birds can come in different size, shape, colors, and beak sizes. They belong in a class of vertebrates known as Aves which includes all birds. They do have claws but instead, they have toes or digits (3 digits), some birds even have toes in their wings which I think is pretty amazing. Toes from their wings help them climb up trees and they can also use them to hold their preys. 

I am holding a round clear plastic cup with a medium size worm inside that has a yellowish color and It's not pleasant to look at. There is something else inside the cup that I am not sure what it is, I would like to know if they eat whatever is inside the cup. The worm has a dark head and there are lines all over its body. It does not have feet or tail but it has two brown eyes at the back of its body. There is also a circle around the brown eyes with things sticking out of it. When the worm moves, there is a long brownish line connected from the head to the back that looks like its spine.

           Today in class, we were given a round plastic clear cup with a larvea worm I believe. It was smaller than normal size worm, with a yellowish color except the head was darker than the rest of the body. It also had two brown eyes at the back of it, with a round circle that has a whiteish color surrounded the circle. There were also woodships inside the cup. The enitre body of the worm was divided into segments, some were bigger and longer than others. It did not have any feet, tail, or hair on its body. It moves in a very distinct way, also it keeps on moving around the cup but did not go in the middle of the cup unless I flip the cup upside down or sideways. When it moves, it pulls the rest of its body closer to the head and repeats the same movement slowly. There was a long brownish color line inside the worm and when it moves, the line either gets smaller or longer, I believe it might be its spine.