I was reviewing the Unit 2 test on chapter 3, and I have a question about the answer to number 6. The question asks : Carpenter ants, termites, earthworms, and beetles are all examples of either carnivores, detritivores, decomposers, scavengers, or primary producers. The correct answer is B: detritivores and I was confused because I’m pretty sure/it says on our handout that earthworms are decomposers. So I guess my question is what is an earthworm’s niche, and is it possible to be a detritivore and a decomposer?
Also, with the demographic transition, the book categorizes Stage 4 as having a declining population. Is that always the case for stage 4 countries?
I have the text book definition, but I was just wondering if someone could clarify why the hypothesis states that ecosystems experiencing intermediate levels of disturbance would have more diversity and not the ecosystems with low disturbance?
Hi folks! It was too close to the test to assign a scribe for today. So, if you are interested in reviewing the nitrogen and phosphorous cycles on line, here are links to two great scribe posts from students (Emily and Evan) in last years APES group:
Like Emily and Raymond, I’m also not really finding the detail the study guide wants us to go into about Ca, Mg and K. I looked online but I couldn’t find much of anything valuable. However, I have a different question. I’m still a little unclear about the difference between standing crop and productivity. The tree and algae examples didn’t really do it for me. Does anyone have a better way to think about it?
I’m a little confused because there’s a huge section for this on the study guide, but the book only says “its important in sending signals between cells”. I remember in AP bio that these help in muscle contraction, but can anyone clarify?
Today we reviewed the Carbon Cycle. The first thing we discussed were the major “pools” or reservoirs that carbon can be found in. The largest quantities of carbon can be found in Rocks (sedimentary), but the carbon located in the rocks can’t be accessed. The second largest “pool” of carbon can be found in the oceans, and the third largest “pool” of carbon can be found in fossil fuels, like coal or oil. Lastly, carbon can also be found in biomass.
The second concept to remember about the carbon cycle is that there is flow, which are chemical, physical, and geological processes that move carbon. The first step is that the atmospheric CO2 can be transferred to biomass through photosynthesis, which subtracts CO2 from the atmosphere. Also CO2 can be added back into the atmosphere by respiration. The way CO2 can be buried is if biomass, that has CO2 in them, is buried into the ground, and eventually with heat and pressure it could be turned into sediments or rock. Another way that we add CO2 into the atmosphere is by extracting fossil fuels. Once the fossil fuels are brought to the surface, the CO2 is brought up to the surface where it can be combusted, which then it will turn back into atmospheric CO2. Lastly, CO2 in the atmosphere and CO2 that is dissolved in water are constantly exchanged through diffusion, which transfers from high to low concentrations. There’s two ways the CO2 into the ocean can be used. One way is into food webs, like algae through photosynthesis, and more will be added into the water through respiration. The second way CO2 can be broken down in the ocean, is by the CO2 reacting with the H2O giving us carbonic acid. Later the Carbonic acid can loose an H+ and give us bicarbonate, and if it looses another H+ it will result in carbonate. This can combine with calcium and give us CaCO3, or limestone shells. This can then eventually turn into rock, where the CO2 will then be stored.
Can anyone explain to me the importance of Ca, Mg, and K to living things and ecosystems? It is question 15 on the study guide, and although I basically understand some of the importance of these elements to ecosystems, I’m having trouble differentiating more specific reasons why they are important.
So I was going over my notes for the Chapter 3 test, and question 21 on the study guide asks you to give an example of each of the five ecosystem services, but I didn’t really understand the example the book gave for resilience. Can anyone give me another example of resilience or better explain it to me?
This 18-minute video was made by me a few years ago. While it is a bit grainy, it covers the major field research techniques I try to show students at Davidson each year. A good review if you have the time: