Ka'aha's+Journal

October 12, 2008 journal: Assigned: What I found at my Kaimuki tide pools was a really good predator and prey relationship between a crab which looks like a brownish white color that blends in with the sand, and also the prey which is a gray and brownish color which sort of matches the crab but instead matches the algae in the tide pool. This is crucial for their survival because either they are going to be eaten or in the crabs case going to be found by the prey. This is a perfect example of a predator and prey relationship because the fish in the tide pool gets it’s food from the algae that it is blending in with so it can survive. Then the crab who is stalking the fishes every move gets to eat the fish if it is fast enough to catch it. It not only needs fast reflexes but also good eyesight or sense because the fish are so camouflaged that if the crab doesn’t see them, then it will not get any food, and without any food it will die. As you can see from the October 12 photos there’s a crab and a fish that is in its predator and prey element. But then there are two types of crab a black one and a brownish and white crab that I am talking about now. But I think that as the crab gets to big for the tide pool and gets easier to find it moves on, onto the cliffs where the waves crashes against them. This is where the boys become men because their shells become a little bit rougher to with stand the constant pounding on their bodies and they get palm size so they can hunt bigger fish then just the smaller ones. They also develop a black and grayish color on their skin so they can best blend in with their background without being spotted by the fish in the near by water. They get their food by staying close to the water where the waves are most rough and they wait for the current to push the fish up against the cliff so they can reach out and snatch them. The crabs on the ledge if they aren’t success full there is a medium sized pool of where the fish gets pushed in by the strong tide. So most of the crabs hang around their to get their food.

Free:

November 2, 2008 journal: Assigned: The sun is one of the many environmental pressures that drives natural selection in my eco zone. Because the sun affects the seaweed, because I noticed that as the seaweed got more closer to the shore it became greener with more nutrients, but when I went out towards the sea it became more of a brownish, green color because of it’s time in the ocean, and soaked by the sea water. I also noticed that the seaweed that was the farthest away from the shoreline it had thorns or sharp things on it and a rougher texture feeling. I think that this is because there is a more chance of fish trying to eat it because it’s closer to their environment. So by coping with the fish the seaweed grew thorn and a rougher texture so it won’t get eaten by fish. The waves and tides is another element that drives natural selection because if the tide is high and the fish goes, where it was just low tide, and in those six hours that it is in the high tide spot, the tide changes and suddenly it is low tide. So the fish has to wait for the high tide to go back so it can go back to the ocean, but if the timing isn’t right and it takes more than 6 hours then the fish is likely to die. So the fish would reproduce and make them survive with limited amount of water, until the high tide comes back. Also the waves that crashes against the rocks affect the crabs that are tanning against them. I think that the crab has a hard shell for predators but also for the pounding of the waves against their body, this is because if your protective shell isn’t strong enough for the oncoming waves then you will die from it. So this drives them to reproduce the strongest shells and the toughest crabs will be the ones reproducing. Another environmental pressure is run-off from the cliff that is right above the tide pools, and because of the heavy rains that we have been having the mud that is not secured by the grass went into the ocean and thus killing fish and other species like the algae. So this is driving natural selection because the fish who can survive this event will be the ones reproducing the fish who can be immune to the water being dirty and unclear. This also can make the algae put themselves in another spot away from a cliff or making themselves more abundance so when it does happen that there is so much of them it can survive after it is all done.

Free: My role is to observe the crab. What I noticed about them was that there are two types of crabs, one has a black and grayish color to it with a rough texture, and another one with a brownish, white, and dark brown. So why is there two types of crabs living closely to each other? Why is one bigger than the other does it really matter? The black and grayish color had has this type of colors because it can blend in with it’s background from predator’s like the birds and us people. Their mostly black and gray because the rocks that they live on are mostly black and gray. These types are crabs are palm size and are much bigger than the full grown adult of the smaller brownish white crab. I think that the brown crab is much smaller because I only see them in the tide pools and not overlooking the cliffs like the black ones do. I also think that they have to blend in with their environment, which is sand and brown seaweed that the tide pool fish eat. Also they are smaller so they don’t stand out as much as the bigger fish. So do you think that the two crabs came from the same ancestor but then their was to much competition so one went to the tide pools and the other stayed the same? I think so because crabs are crabs and have the same body structure as one another no matter its size. But then their might be competition if they are living in the same niche so one has to cope for another so they can both survive and if they don’t cope then the strongest survives and the other dies out. Exploring at the tide pools I found a couple of crabs skeletons in the pools. I wonder what could have eaten the brownish white crabs instead of its relative the black crab? I thought that because there is more deaths of small crab then bigger crabs is because they are smaller than the others, so they can be eaten easier without a big fight. I also think that there is more than one predator. I think that there is the eel which can eat anything and the fishermen says there is a lot of them near the tide pools. Also the octopus which can eat fish and crab for dinner. And also if their not in the water then if their on land they can be eaten by birds passing by for a snack.