Review Guide: Ecology
Ecosystems (Ch2,3):
1)What are the definitions of ecosystem,habitat, community, population, biome, niche? Choose an example of an ecosystem and describe these terms with specific organisms in this ecosystem.
2)Biotic and a-biotic factors – Give 3 examples of each in an ecosystem of your choice.
3)Why are the producers and decomposers the most important components for the stability of an ecosystem? What would happen if any one of them is absent or eliminated?
Feeding Relationship and Energy flow(Ch 3):
4)Food chains: Draw a food chain and identify the trophic levels of the organisms, starting from the producers to the highest order of consumers. Use two sets of terminology – Producer-herbivore-carnivore 1st, 2nd, 3rd and producer-consumer 1st, 2nd, 3rd etc.
5)Food webs: know how to build one from a list of organisms. What is the advantage of a food web over a food chain for the stability of the eco-system?
6)Food webs: Consider a complex food web of your choice (from the text-book or Google-search for an image of a “food web”). What might happen to the organisms in the web if you eliminate one of the organisms (by sudden predation, chemical poisoning or other changes)? Repeat the procedure for a producer, a high-level consumer and for an organism with many connections in the web.
7)Energy Flow: Where is the energy going, starting from the captured light energy, and all the way to the highest level consumer?
-Draw a flow chart for the energy flow, including: sunlight, waste (heat), use through the formation of ATP, storage in organic molecules (carbohydrates…). (Mentioneating, photosynthesis, respiration).
8)Energy Loss: Why is thetotal biomassof decreasing as the trophic level goes higher?
9)Energy Pyramid and food chains: Why are most food chains no longer than 5 trophic levels?
Cycles of matter (Ch2)
10)Study the carbon/oxygen cycle, thoroughly:
-What would happen if any of the components of the cycle would be eliminated?
- Plants and phytoplankton play two opposite roles in the C/O cycle. What are these two roles?
- Where is the carbon other than in atmospheric CO2?
-What is the role of bacteria, fungi and other decomposers in the cycle? What happens to the atmosphere if there is too little or too much of them?
11) Study the principles of the Nitrogen cycle:
-Although nitrogen gas is the most abundant gas in the atmosphere it is considered to be a limiting nutrient for plants and animals. Explain why. What needs to happen for this nitrogen to be used by plants?
-What are the roles of different kinds of bacteria in the nitrogen cycle?
-Fertilizers: What are they for? Why do they contain mostly nitrogen, phosphorous? (and not carbon sources, for example).
12) The water cycle – Draw the cycle.
-What are the major parts?
-What is the role of plants and animals in the water cycle?
13)Interactions between cycles:
-Global warming: What would happen to the water cycles if there is too much CO2 in the atmosphere? Consider all the water reservoirs – both liquid and frozen water .
-What would happen to the levels of CO2 and dissolved oxygen if nitrogen-rich fertilizers leek into rivers or into the ocean (In other words – what is Algae bloom, and why is it dangerous?)?
Populations – growth and interactions(Ch 4):
14) The size of a population at any given time is determined by four simultaneous processes – what are they?
15) What is exponential growth? Explain and draw a typical exponential graph. - Under what conditions does it occur?
16) What is logistic growth? Explain and draw a typical logistic graph.
-Under what conditions does it occur?
-Draw a logistic growth and explain what happens at five critical points along the way, including lag, rapid growth, fluctuations, reaching carrying capacity.
-Consider the limiting factors, the rate of births, rate of deaths, balance between the two.
17) What are possible limiting factorson population growth? Choose two very different organisms (for example, a plant, an animal - herbivore or carnivore, a protist (paramecium), a fungus, a bacterium, a human) – list three biotic and two a-biotic limiting factors for each of the two organisms.
18) How does the population size of organisms become stable?
19)What changes in the environment can affect the carrying capacity of a certain organism? – Including entry of competitors, producers, individuals from the same population.
20) Interaction between populations: competition, parasitism, predation, mutualism, commensalism.
-Understand the types of interactions.
-Draw two growth curves of an organism of your choice: One - when it is alone (with its food), and the other - or when it is mixed with its predatororwith its competitor. Explain your drawing in detail.
Biodiversity (Ch5):
21) Why is an ecosystem more stable, resistant to changes, if it has a larger biodiversity?
-(Guidance: why is a food web more resistant to changes than a food chain)
22) Non-native (invasive) species:
-Where do they come from and how?
-Why do they tend to be more successful than the native species?
-What harm do they cause to the stability of the ecosystem?
23) Adaptation: Understand a few examples of how organisms are adapted to their surrounding in their structure, behavior.
-How can organisms avoid dangers, including competition by developing their niche (see p. 91).