David+Yoshimoto's+Journal

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The area I am focusing on is a small section of the stream about seven feet wide and six to twelve inches deep, the deepest being around a foot while the shallowest part were three to six inches, which most animal life cannot escape from due to being fed by a series of small falls and ending in rapids. The pool of water is calm, cool and very clear even with a coat of sediment along the bottom due to the water flowing at a snail’s pace. The dark brownish sediment is mostly made up of rocks and dirt as well as some decaying leaves which provide small animals with cover. There is a large amount of plant life such as Au, a banana tree, algae on the underwater rocks not coated in sediment. There are a lot of aquatic animals in this area too such as Mosquito fish, swordtails, frogs, prawns, mosquito larva, and other small unrecognizable fish. Non aquatic life included ants, chickens roaming around at the edge of our sight, doves, a few bees crawling on the rocks and buzzing around us, flies, a large amount of mosquitoes, and a few spiders with their webs strung between plants over the river but one thing that I noticed was the lack of dragonflies, which explains the overabundance of mosquitoes. The abiotic factors that influenced our environment were large rocks changing the terrain under and atop the water as well as the mountain of sediment evenly covering the river floor.======

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This spot is a good area to work because I can find a lot of predator prey relationships such as the mosquito larva and the mosquito fish, the algae and the swordtails, the frogs and the flies/mosquitoes, and the chickens and the frogs. Also in this area there is a menagerie of niches ranging from those of peaceful herbivores, swordtails and mosquitoes, to the vigilant predators, ants and frogs. Just by taking a quick look at the area I could think of a small food web, plants to bugs, larvae to fish, fish to prawns and birds, birds to death, bodies to soil, and soil to plants. Also by a quick glance I am able to think of a few environmental pressures that could be driving Natural selection in the eco-zone; such as the small amount of niches underwater as opposed to on the surface, recently the rising temperatures, and much more. All in all I believe that this area is a very good place to work on my semester project.======

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A predator prey relationship that I was able to see evidence of was the mosquito fish and the mosquito larva. Just by spotting the mosquito fish as well as noticing the mosquitoes buzzing around me, and their larvae in the water I knew that the mosquito fish had to be preying on the mosquito larva. The mosquito fish themselves must not be getting quite a lot of competition for food because there were no dragonflies, the mosquito’s main natural predator, present or around my eco zone and because there are still so many mosquitoes, which means that the mosquito fish are not doing a very good job controlling the population. While the mosquito population itself is doing well, but most likely in either the exponential growth phase or it is at its carrying capacity, but it is definitely not struggling for existence. The mosquitoes are very lucky that they are only preyed upon when they are in their larva stage and when they get past that they have very few predators. If there were predators which mainly preyed upon them in their adult stage there would be a lot less mosquitoes.======

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The mosquito fish are extremely lucky, even though we are not, that they don’t have any completion for their prey. It shows that the mosquito fish are specialists and have eaten their way to being the top contender to eat the mosquitoes to extinction. Which is a good thing and a bad thing because while mosquitoes are a disease spreading, very annoying animals, but if the mosquitoes were to die out then the mosquito fish would die out as well and if the mosquitoes ever make their way back to Makiki stream then their population could grow freely causing tons of grief for humans.======

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Lastly the mosquitoes are flourishing so what that means that the population of mosquito fish is also in an exponential growth or logistic growth. But soon the population of mosquitoes will drop due to the amount of predation and the population of mosquito fish will follow suit. Then when the population of mosquito fish drops, there is less predation so the population of mosquitoes will rise causing the population of mosquito fish to rise. And this cycle will keep repeating unless another predator of either the mosquito fish or the mosquitoes is introduced to the habitat, causing one or both of the populations to grow or plummet without stop.======

Entry #2

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There are many insects in the area that my group is observing. There countless ants crawling along the ground and on rocks, especially on surfaces that were not touched by direct sunlight. And the ants were especially swarming the shady sides of rocks that are porous. Other, less abundant, insects whose main form of locomotion is flying are, millipedes, spiders, and cockroaches, and all of these insects were darkly colored. I only noticed a couple millipedes crawling on the sunny side of rocks, and several cockroaches crawling under plants. Spiders and their webs spanned between nearby plants, overhanging the water, as if they were going to go diving for food. The bugs, except spiders, that did not use flying as their form of locomotion, ants, cockroaches, millipedes, did not crawl on the plants, but only on the dirt or rocks, most likely to make themselves less noticeable by predators because they blend in well to those surfaces. The insects that used flying as their main form of locomotion were mosquitoes, flies, and bees. These insects, except for bees, were mainly gathered around us, people, making it hard to carefully watch their habits without human presence. Bees, however, even though I only saw two of them, they were constantly landing on rocks, and seemed to take a quick bask in the sun. This seems odd to me because I would believe that bees would be hovering over flowers, looking for a good one to sap nectar from. Also I noticed mosquito larva swimming in the stream. Because the stream was flowing more rapidly than my last visit, they were gathered in little pockets of calm water that were not affected by the remainder of the fast moving stream. The small pockets that I have just mentioned also had plants growing inside the water, possibly offering the mosquito larva some protection. The larva mainly were just floating there, even when a mosquito fish loomed closer they just kept floating there. I noticed that the mosquito fish did not even seem to notice the mosquito larva, let alone prey on them. The only bugs that I found were in abundance are the ants and mosquitoes. I believe that these two are found in abundance because, for ants, a lack of predation, and for mosquitoes, the ability to reproduce quickly and efficiently, laying tons of eggs to increase the number that would grow into adults. ======

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Some environmental pressures that could be driving natural selection in my eco zone are; the amount of predation which changes the amount of prey the survives, the speed and height of the current that could be changed depending on the amount of rainfall that fell recently, and the color of surfaces that animals live over such as dirt or sediment on the bottom of the stream. The amount of predation affects mosquitoes because if there are more predators then the mosquitoes who grow into adults faster have a better chance of surviving and passing down that variation to future generations because if they grow faster then they have a much smaller chance of being eaten by mosquito fish, who are the mosquitoes’ main predators, whom only prey on mosquito larva. Also faster fish would have a larger chance of survival because they would be able to escape predators and catch food more quickly and efficiently unless they are a herbivore, in which case they would only need speed to escape predators. Because a faster fish would have a larger chance of accomplishing these two things they will live longer, and therefore have a larger amount of mates, allowing it to have more offspring which may carry on this genetic variation. Also animals that are darkly colored, dark brown or black, have a larger chance of surviving than animals with brighter colors because on the land and in the water the color of the ground is a dark brown. One animal that blends in well are ants, they travel on the dark brown dirt or on the parts of rocks not hit directly by sunlight but not on the grass, which is bright green, or the parts of rocks directly hit by sunlight. These ants have a higher chance of survival, and therefore can serve their queen better so the queen can produce more offspring. Also large fish have a larger chance of survival than smaller fish because they are less preyed upon and are less affected by a fast moving current. Also large fish have a larger amount of food because they can eat all of the organisms below them on the food chain, whereas the smaller fish have a lesser amount of food because there are a smaller number of organisms below them on the food chain. And because large fish have a better chance of survival they have more chances to mate, and therefore, pass on that variation to more offspring. ======

Free Journal Entry #3 Date: Sunday, November 23, 2008. On this visit to our Eco-zone at Makiki Stream, we found the entire area utterly devastated by the heavy rain the previous day. We estimated the water level had reached at least two to three feet higher than normal. This destroyed the plants on either embankment of the stream. Also, all of the small rocks at the bottom of the stream were pushed off to the sides. Only a few small fish were visible, it was difficult to determine what kind of fish they were, but I believe that they were mosquito fish. Those few fish that were left were swimming in areas sheltered from the current by rocks. Any other aquatic life was hidden from view, either hiding in the sediment, or nonexistent, completely wiped out. Nearly all insect life was wiped out; no ants were visible, cockroaches gone, bees and flies hiding, and spiders carried away by the current. Only mosquitoes were left, as soon as I arrived they began to bite me, desperate for blood. But I could not see any mosquito larva, even in the calm parts of the stream. Also, I noticed that the chickens and roosters that also inhabited the area were wandering around more freely than before, seemingly scouting the remains of the heavy rain. The plants, as I have mentioned earlier, were completely knocked over, carried downstream by the current, or utterly destroyed. There were very little aquatic plants left in the stream, and the bottom of the stream was barely visible. The fish, mosquito larvae and plants that once inhabited the stream were most likely carried farther downstream by the heavy torrent of water that probably washed over the area the day before. Now, as far as we could see, it may take a while for the stream to recover the animal and plant life it once had. From my previous observations, these are much, much different. Many of the animals and plants once there have now disappeared and many experiments that I thought that I would have been able to conduct are also null and void. And when the stream gets closer to returning to its former glory, testable hypotheses are; if the water is calmer then more aquatic plants will be able to grow, if the water is deeper then more aquatic life will be able to grow, and if there are a larger number of large rocks (size of football) then there will be more insect life. Biology Semester project Journal #4 It has been two weeks since the heavy rain has wiped out almost everything living in our eco zone, but nearly everything has grown back since then. There is a large abundance of small fish that were not present prior to the storm. I observed the small fish gathering in the calmer portions of the stream. In one place there was a huge congregation of fish on a flat rock that was mostly sheltered from the sun in by rocks forming a small six inch wide peninsula of water. Also many ants were now present, once again swarming all of the rocks surrounding the water. I found a pool of water, about five by three feet and four inches deep, that was not connected to the stream and was most likely formed during the stormy weather 2 weeks ago. That pool of water was filled with at least twenty small fish, darting about in the water. One strange happening that I observed was that a millipede was underwater, and still very much alive. It was crawling along the bottom of the stream and it still seemed to be fine because when a fish brushed against it, it curled up into a ball like a normal millipede. I even found spiders returning, I noticed a few spiders crawling around the rocks as if searching for a place to spin a web. Something amazing that I saw was a huge crayfish that was walking along the shallow part of the river. But before I could take a picture of it or get a better look at it, it hid under a huge rock, and despite my efforts to coax it out, I never saw it again. My chosen hypothesis was, if the water is deeper, then more aquatic life will be able to grow there. I tested this by first thinking of a scale that would determine the amount of aquatic life. I measured by the amount of fish captured with one sweep of a net (12 inches in diameter), when the net was put horizontally into the water and when the entire net is submerged I swept the net back to the surface by sweeping it like a door on a hinge that touched the surface of the water. Depth of water || Amount of aquatic life || 24 inches || 20+ life forms** || 18 inches || 15-17 life forms* || 10 inches || 11-13 life forms* || 6 inches || 5 life forms || By doing this experiment I found that there is a larger abundance of fish the deeper the water is. Most likely because water level is shallower, there is more net underwater at the time of sweeping. But there is also an apparent abundance of life forms in the deeper water. I believe that because the water is deeper there is more room for life forms to grow. Also the fact that there is more room for the life forms also means that there is more food and resources for a large population to be supported.
 * estimate because very hard to count that many
 * at least more than this