Alane Thompson
Biology 101 Dr. Ferdinand

The cell is the basic unit of life for all living things, while the DNA is the design for all passed down characteristics in living things. Both the cell and DNA have been studied and linked to the evolution process. From the beginning of the eukaryote cell unto the prokaryote cell there has been changes and the same goes for DNA. Changes in DNA sequences has contributed to different yet similar species over great periods of time.
The cell which first existed in its prokaryote form of bacteria can be divided into two domains, domain Bacteria and domain Archaea. Prokaryotes are organism with a single cell and does not have a nucleus enclosed in a membrane. There are no organelles within the prokaryote cell and it reproduces on its own. This cell can reproduce two daughter cells out of one parent cell by cloning itself. This is done by asexual reproduction or as spores and can multiply into billions of cells without the assistance of other cells. Cells produced by binary fission produce two separate cells and cells produced as spores produce more than two cells at a time. These types of reproduction does transfer genes but they are not replicated between the cells it produces. Each new cell now have the growth potential of the original cell.

The Prokaryotic cells are much smaller than the eukaryotic cell (which will be discussed further along) and have great diversity. This cell (prokaryotic) preexisted long before the eukaryotic cell and have a far greater variation of metabolism sources than that of the eukaryotes which is the reason for their differences. The sources used can be through photosynthesis, organic and inorganic compounds. This variation of sources also help enables the prokaryote to flourish in different environments and harsh conditions such as extreme heat or extreme cold as well as high salinity. In addition to these prokaryotes (which are much smaller than eukaryote cells) also live collectively in and on the bodies of other organisms. An example of this is the bacteria that live on humans that coat the skin, the bacteria that reside in our mouth (which can cause infections) as well as the E.coli that resides in our intestinal tracts which is helpful to us. There are probably more prokaryotic cells on or in us than eukaryotic cells which we are made of however there are more prokaryotes on this earth due to their rapid rate of growth. The third domain, Eukarya may be more familiar. It has four kingdoms, protists, plants, fungi and animals. Humans are in the domain Eukarya, kingdom Animalia. Eukaryote cells differ from prokaryote cells in many ways they are much larger and range from unicellular to multicellular organisms. The main distinction is that eukaryotic cells have a membrane-bound nucleus that contains its DNA, organelles that are also enclosed into internal membranes and a cytoskeleton to act as support for the cells contents inside and provides the cell’s shape. The DNA is in every cell and it has the hereditary information necessary to construct and preserve an organism. Eukaryotic cells reproduce sexually. When two same species reproduce the ovum and the sperm cells fuses together during fertilization and produce an offspring derived from the two whose characteristics come from a combination of the parent organisms.

This genetic information is passed onto the offspring through chromosomes. Chromosomes are bundles of DNA and each parent gives 23 pairs of each of their chromosomes to their offspring. The genes of the offspring are also influenced by segments of DNA and is the reasons for how we look and function. The genes are different between species and individuals are different. The changes resulting from the varying DNA information in eukaryote cells have produced changes over time of the shape, size and function of different body parts thus leading to new and different forms of life. Species have changed and diversified since the beginning of the time but the origin of each species can still be traced. DNA can be extracted from living cells and fossils as well and upon comparison it will show the alikeness of any two or more species to one another.
Studies of DNA have likened human beings to chimpanzees as well as the group of hominids (human-chimp ancestors) called the Neantherdals. Comparisons in DNA later dispute that modern humans are the Neantherdals true descent but it is still true of the likeness to chimps. DNA studies from today’s living human and or organisms have led to the revelation of extinct species and shows the history of their migrations. This is shown in the sequence of their DNA which is structured from Guanine, Cysteine, Adenine and thymine and the sequences may change and vary by a very small percent but it can make significant differences in different species although they have similar backgrounds. All these changes are due to mutations of DNA that happen spontaneous or changes in chromosomes and they way they shuffle and mix themselves around in variation. There are two DNA types that do not change sequence or combine with other DNA and this is how millions of years can be researched back and that is

the mitochondria and the Y chromosome. The mitochondria pass along from the male and the Y chromosome passes throughout the female generation from mother to daughter to their daughter and so forth the same going for the male species.
Natural selection assists in the change of environment when the species cannot adapt to its surroundings it becomes survival of the fittest. Competition for resources if not won results in death of the unfit of the species and the more adaptable of the species survive and produce more like itself. These new species have different capabilities and have new inborn habits and changes so it is now able to survive until there is another species who arise and produce another variation once again. This occurs over and over and is the reason for so many different types of the same species in different locations and under different habitant situations. Cells and DNA have a very strong influence on evolution and is the source of variety. Without this variety and change extinction would occur of more species so it is very important to maintain the existence of life. Modifications and mutations in species help them to survive or die out and evolve with differences that are helpful for keeping species diverse and alive or from being wiped out.