Science Class: Ecology

I have so many posts for, it seems, everything but class reflections and I figured I should solve that dilema do one to study for the test tomorrow, so here goes!

In class, we've been studying ecology, or the study of the relationships and interactions between living organisms and their environment. So, here are some vocabulary included in the first section (I know it's boring, but I need to study, so bear with me):

Environment: consists of all the non-living and living things in which an organism may interact.

Ecosystem: All the living and non-living things in a given area. The size of a ecosystem is defined by the ecologist studying it (e.g. a drop of pond water or an entire ocean- big difference there, but it's still up to the ecologist)

Ecologist: someone who studies ecology

Community: Consists of all the living organisms in an ecosystem

Population: A group of organisms of the same species (I think of it as the number of organisms of the same species)

Habitat: Where an organism lives.

Okay, now I will try to discuss this bit in an interesting and amusing manner. All of these technical definitions make my head spin, and it raises some questions: First, if the definition of an environment consists of all of the things that an organism may interact, then what about the things that an organism doesn't interact? Is there even such a thing that we can't interact with? (Dark matter doesn't count because a) nobody knows what it is and b) I don't get what it is!) Also, if an organism dies, is it still an "organism"? So is it taken for granted that organism in all of the definitions refers to a living organism? Are there even "official" definitions for all of these things? Anyway, there is an interesting website called "Kids Do Ecology" that I found. Here's a link: http://kids.nceas.ucsb.edu/ Some of it we learned, some of it we didn't. Apparently, ecology (from Greek) translates into "study of the household," so we are studying the "house" that we live in: Earth. There were also two new vocabulary words: abiotic factors, which are non-living factors, and biotic factors, which are living factors.


The next bit that we learned about were the different energy roles and food chains/webs. There are three main energy roles: producers, consumers, and decomposers. Producers produce their own food. The best example of this are plants: they take sun, air, water, and nutrients from the soil and photosynthesize to make food. However, in the ocean, the producers (surprisingly) aren't plants. Link time! http://kingfish.coastal.edu/biology/sgilman/770PlanktonBenthos.htm Annoyingly, while I did learn quite a bit from it, most of it I didn't get and it didn't answer my original question (which I will get to later). Interestingly, the producers in the ocean are phytoplankton, algae, and seaweed, but those are not plants! I honestly never knew that, I assumed they were plants. Interestingly, phytoplankton is generally not a major source of food. Algae, or mainly diatoms since they're slightly bigger, are eaten a lot. However, I wanted to know what were the producers at the bottom of the ocean, where no sunlight falls. I thought it was the tube worms that feed on sulfur from the vents. However, according to this webpage, http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/oceanography_recently_revealed1.html, it is actually bacteria that convert the sulfur into energy through a process called chemosynthesis. The bacteria live inside the vent worms, nourishing it. Okay, enough about ocean producers, we must move on. Consumers are organism that feeds directly or indirectly on another organism. There are four special types of consumers: herbivores, carnivores, omnivores and scavengers. Herbivores eat producers, carnivores eat consumers, omnivores eat everything, and scavengers eat dead organisms, which is usually meat but sometimes plants as well. However, isn't a scavenger a type of carnivore, herbivore, or omnivore? Also, if scavengers eat dead organisms, then how dead does it have to be? We are omnivores, but our food is most definately already deceased. Moving on! A food chain, by what the textbook says, is a series of events that transfers food and energy from one organism to another. I honestly hope we won't be tested on that specific definition. Food chains always (as we were taught) start with producers, then consumers, then the decomposers link the tail end to the front. An example would be: Grass -> Rabbit -> Fox-> Bacteria. However, shouldn't the resources that producers use be the start of the food chain? A food web is a bunch of interlinked food chains. Here is an example (I never knew uploading pictures could be so difficult):

From: http://www.biologycorner.com/resources/foodweb1.gif

The decomposers in this picture are very enthusiastic bacteria, so they have spelled out "Bacteria" and all of the arrows for you, but since they are microscopic, you can't see it. There are many food chains in this food web, like leaves -> mouse -> fox -> bacteria. Food chains are better than food webs for the survival of the community because removing one link in a chain will destroy the chain. However, if we remove one link in a web, then the web can adapt. For instance, if I removed leaves, then it will impact the web but not necessarily destroy it. Why? Because the mouse, which eats leaves, will eat more grasshoppers instead. The grasshoppers, which eat leaves and berries, will simply eat berries only. Of course, chances are the populations of a lot of organisms in this web will shift because of the removal of the leaves, but the web itself will survive. This is also a good time to introduce something else we learned in class: energy pyramids. The basic concept behind an energy pyramid is to show energy transfers and how the amount of energy available decreases as you go up the pyramid. To start, let's begin at the bottom: producers. Producers have the largest amount of energy because they make their own: of course they use some of it, but some of it also goes into the actual producer. Going with the food web above, let's put leaves at the bottom of our food web. Now, let's say a primary consumer, a mouse, comes and eats all of the leaves (let's say six to keep it simple) off of a plant. The plant got more energy than the mouse did because the mouse only got the energy in the plant. However, the plant doesn't just store energy, it also uses it. So, to make up fictional units of energy, let's say the plant received 1,000,000 pippins of energy in its lifetime. It used 990,000 of those pippins to grow, make more energy, and do whatever plants do. There's only 10,000 pippins in the actual plant, which the mouse eats. Therefore, the mouse gets 10,000 pippins from the plant. However, the mouse got eaten by a fox! Through this time, the mouse used up 9,900 pippins from the plant for running, finding more food, chatting with other mice, and doing whatever mice do. The fox only gets 10 pippins indirectly from the plant. Pretty small compared to the 1,000,000 pippins that the plant had!

Finally, the last section talks about different types of interactions, relationships, and adaptations. I am hoping to speed up this process, but I don't think that will happen. A niche is an organism's role in the environment-what it does, needs, where it lives, etc. Two species may not occupy the same niche at the same time because it would create enormous competition. It's like someone coming and saying that they'll be you for a day: you won't like that, and both of you would be competing to see who gets to be, well, you. Competition is when two or more organisms have to struggle (i.e. compete) against each other to get resources to survive. The driving force in competition is survival (but then again, doesn't that drive everything?). Organisms deal with competition by either adapting, dividing up the habitat (I'll eat this flower and you'll eat that flower), moving, reducing the competition, or if they cannot do any of these things, dying. Predation is the type of interaction is when an organism kills another organism for food, although this is a little fuzzy. The predator is the organism that eats the other, and the prey is the organism that's being eaten. However, I say that this is a little fuzzy because if you really pay attention to the wording, that means that almost everything besides producers are predators: after all, we eat dead plants, right? They are already picked and not alive by the time it gets on our plates. Of course, you don't necessarily have to kill to get food, like bees harvest nectar to get honey to eat, but most creatures don't consume things and keep it alive. Organisms can adapt to predators and vice-versa by adapting to run fast, grow hard shells, have different colors, etc. Finally, my favorite (because it's interesting): symbiosis. Symbiosis is a close relationship between two organisms in which one lives on, near, or in the other organism and at least one organism is harmed. There are three types: parasitism, commensalism, and mutualism (they aren't usually listed in that order). Parasitism is the type of symbiosis in which one organism benefits and the other does not. The parasite benefits, the host does not. For instance, the strangler fig tree and the other tree that we saw in class the other day is an example of parasitism (yes, I'm just repeating what was said in class). The strangler fig tree sprouts in the canopy of the rainforest and grows downward, wrapping its roots around its host tree. The host tree, while not really "strangled," cannot grow any larger, and is slowly killed by the strangler fig tree by which point should have reached the ground. Commensalism is when one organism benefits and the other is not affected- nothing good and nothing bad happens. For instance, ravens would hang around wolves because they can get a free meal when the wolves are done eating, since they leave scraps once they're done eating. I found a website that says that the symbiosis between a clownfish and an sea anemone is commensalism, but people could argue that it's mutualism because the clownfish gets protection and attracts prey for the sea anemone. (http://www.owc.org.mn/econet/html/commensalism.htm) Mutualism is when both organisms benefits. For instance, an interesting example that I learned from when I was in second grade was a sea anemone and a crab- that is, the sea anemone rides on the crab. I won't tell why it's mutualism, it's a puzzle for anyone out there to figure out. Another type (we studied the ocean really in-depth in second grade) is coral and algae. The algae is safe inside the coral, which is the benefit for the algae, and the algae provides important resources for the coral. While I did learn this in second grade, here's a link for further reading: http://oceanservice.noaa.gov/education/kits/corals/coral02_zooxanthellae.html.

Wow, that took a really long time! In ecology overall, though, I find myself thinking a lot about the stuff I learned from second grade, the magic school bus series, and all those science videotapes that I had to watch. I didn't really think I knew much, but there seems to be random facts in the corners of my brain that pop up all the time. It's definitely been quite interesting.