Second+Visit+Journal

We visited the stream for the second time on Saturday, November 1 at 3:30 pm.

1) **Free Journal Entry:** In this free journal entry, ask questions about what you observe that relate to your assigned role. For example, you might notice that plant life is abundant on one side of the stream but not the other. Why is that? Or you may see Fish in parts of the stream with low current but none in areas with high current. Why is that? Ask authentic questions that you may be able to answer further down the road of this project.

I chose the role of observing the animals in our group. During our first visit we looked at some of the underground animals, some of the birds, and some of the water animals. But during our second visit, I payed more attention to the water animals. After observing our eco-place again, I had some questions about the animal life. When I just looked straight into the water there was nothing to see except some small little guppies dashing around. But when we got the net and fished around under the roots of the tree (parts in the water), we caught some crayfish and plecostomus. My question is why do plecostomus and crayfish only live under the roots of the tree? Also, why do the fish live in low currents and not in the areas with high currents? I would think that the fish would have an easier time picking up small things floating in the current if they stayed in the areas with high currents. How come in some areas with low current there would be fish, but in other areas with low current, there wouldn't be any fish? Even though I didn't do much observing of land animals during this visit, I wondered about the ducks and birds. Why do the ducks only stay in certain parts of the stream and chase all of the fish away? Why don't they go to a new place where all the fish have migrated to? Why are there so few birds in the trees? The only times that I see them is when I hear them singing a song and look around for them. But they are very hard to spot between all of the leaves and branches. As I observed the few crayfish that I could see, I noticed that they swim backwards in a sort of pumping motion. They propel themselves so that they move with their butt going first. Why do the crayfish swim this way? When I moved over to the area where the ducks roam, I noticed that there were many fishes there. I wondered why the fishes go where the duck are because I would think that the ducks would eat all of the fish living in that area. If it's such a dangerous area for the fish, since their predators (ducks) hang around there, why don't they just move more down stream where the ducks don't go?

2) **Assigned Journal Entry:** A predatory pressure that is driving Natural Selection in our Eco-place is the large bass that eat the guppies in the stream. Since the bass would ideally eat the slow fish, the fish would have gotten faster through Natural Selection. The slow fish would be eaten, so there would be less slow fish to reproduce, causing the next generation to have less slow fish than fast fish. Eventually the whole population of fish would be quick. Three examples of organisms in my eco-place with heritable variations would be the colors of the male fishes, the size of the crayfishes' claws, and the speed of the fishes. •The colors of the male fishes would be a heritable variation because of sexual selection. Like peacocks, the male fishes are decorated with beautiful designs on their body that attract the attention of the females. The females choose the prettiest males and then reproduce with them. Then the next generation has fish with more attractive bodies. The females of the species are also ugly and fat compared to the males. The females don't need to have pretty bodies because they're the ones choosing who they want to mate with. In this case, there could be two male guppies. One guppy could have an ugly colored body, and the other could have an attractive colored body. The attractive one would be more fit because it would have more opportunities to reproduce. •The size of the crayfishes' claws would be a heritable variation because the crayfishes with larger claws would be able to catch more food. Since the crayfish with the larger claws would be able to get more food, they would have more "survivors" to reproduce for the next generation. So Natural Selection would cause the next generations to have crayfish with larger claws. The crayfish with the bigger claws would have a better chance surviving because they would have an easier time quickly moving to snatch small passing fish. In this case, there could be two crayfish. One could have large claws, and the other could have small claws. The crayfish with the big claws would be more fit because it would have an easier time snatching the small organisms in the water. •The speed of the small guppies a heritable variation that is caused by the large bass in the stream. Since the large bass would eat the slow guppies, more of the fast guppies would survive. Then there would be more fast guppies in the next generation because of Natural Selection. In this case, there could be two guppies. One could be fast and the other would be slow. The faster fish would be more fit because it could evade its predators easier.