Plants are incredibly designed organics, vastly different from most other forms of life. One of the features unique to plants and a few microscopic organisms is a cellular organelle referred to as the chloroplast. Chloroplasts perform major services for the plant, the most crucial of which is making food for the plant by means of photosynthesis. Since this organelle is so crucial to plants, and other organisms successes, it is natural to ask where it came from and how it works. This article will attempt to answer both of those questions as they relate to the great origins debate.
Chloroplasts are found in plant cells, algae and a few microorganisms such as Euglena. They are found throughout the cell and can move freely to adapt to changes in lighting. This is crucial because the chief function of chloroplasts it to perform photosynthesis, which requires sunlight. In order to perform this tasks, chloroplasts are filled with a pigment called chlorophyll. Chloroplasts in plants generally are ovular in shape, while those found in other life forms vary in shape depending what they are found within.
Chloroplasts have an inner and outer membrane and a third, specialized membrane called the thylakoid membrane. The thylakoid membrane floats on the gelatinous fluid inside the chloroplast referred to as the stroma. The stroma houses the chloroplasts mini-organelles, including ribosomes, and is the site of sugar fixation. Scattered throughout the stroma are small starch granules, which are made during the day as photosynthesis occurs. At night, most if not all of these granules are consumed to feed the cell.
Within the specialized thylakoid membrane are stacks of what appear to be tiny cookies or small coins. Each individual coin is referred to as a thylakoid. The stacks themselves are called grana. A specialized structure called the stroma lamellae holds the thylakoids in place and at the proper distances from one another. This allows for maximum surface area exposure to the incoming sunlight and thus the maximum output from the photosynthetic process. The individual thylakoids are the sites of photosynthesis. There are two types of thylakoids. The ones found in the grana are called granal thylakoids and perform the light gathering portions of photosynthesis. ATP, cellular energy, production takes place in the other thylakoid type, the stromal thylakoids, which connect directly to the stroma, hence the name.
Chloroplasts are somewhat unique among cellular organelles in that they have their own DNA, which is unique to themselves. In some plants, chloroplast DNA has been sequences alongside the plant itself. The approximately one hundred genes in most chloroplast genomes code largely for either protein synthesis or aspects of the photosynthetic process. However, DNA in the nucleus of the cell codes for the vast majority of the proteins a chloroplast needs to survive, meaning that the two must work together to keep the chloroplast functional and the plant alive. When replication of a chloroplast becomes necessary, it will replicate asexually by simply splitting itself in half.
With so much intricacy and so many complicated and coordinated processes involved, it would seem reasonable to expect that evolutionists might consider the chloroplast something of a sore spot for their theory. That, however, is not the case. Evolutionists embrace a theory called endosymbiosis. The theory calls for a eukaryotic cell, such as an amoeba for example, swallowing a cyanobacteria approximately two billion years ago. The cyanobacteria, which lacked a nucleus, was not consumed as would be expected. Instead, it and the nucleated cell that captured it developed a symbiotic relationship. The cell ceased to feed, relying on the energy produced by cyanobacteria to feed both of them. In return for feeding the nucleated cell, the cyanobacteria gained shelter and safety. Over the billions of years between that event and the present, this symbiotic relationship spread throughout the evolutionary tree of life to thousands of species. Also during that time, the cyanobacteria, now known as the chloroplast, transferred much of its DNA to the cells nucleus, conferring an evolutionary advantage to said cell and increasing its survivability.
The above explanation is, as some of you may have recognized, purely a work of science fiction for which there is no evidence beyond tortured evolutionary data twisting. Supposing for a moment that an amoeba or similar organism did engulf a cyanobacteria. When they do so, the unfortunate organism is encased in a phagocytic vacuole, which will eventually break it down and transfer the acquired nutrients to the amoeba. How did the cyanobacteria escape death in the phagocytic vacuole? And, supposing that it did, why did it decide to start sharing nutrients with its new host that had just tried to eat it? Sharing of nutrients is the opposite of evolutionary ideals, which are universally selfish. Even supposing the first two questions could be answered, that still leaves the question of how did the amoeba know that the cyanobacteria was beneficial and thus not try to encase it in another vacuole?
The evolutionary explanation for chloroplasts feels like something of a cop out. There is not a good evolutionary explanation for how the chloroplast developed so they turn to accidental symbiosis, which defies evolution anyway. It takes far less faith to believe that God designed plants and other organisms with chloroplasts so that they could produce their own food and be food for other creatures in the Garden of Eden.