Jeopardy. Population size. Population Growth. Succession/ Symbiosis. Water Quality. Food Chains. Q $100. Q $100. Q $100. Q $100. Q $100. Q $200. Q $200. Q $200. Q $200. Q $200. Q $300. Q $300. Q $300. Q $300. Q $300. Q $400. Q $400. Q $400. Q $400. Q $400. Q $500.
a. Autotrophs, heterotrophs.
Rank the following in order from largest to smallest: Organism; ecosystem; community; biome; biosphere; population.
Organism, population, community, ecosystem, biome, biosphere.
Put the following into a food chain:
Deer, wildflower, fungus, vulture.
Which of these are heterotrophs? Autotrophs? Producers? Consumers? Decomposers?
Wildflower --> deer --> vulture
Consumer/heterotroph: deer, vulture
Which level of an ecosystem would likely have the highest levels of accumulated toxins: producers, primary consumers, secondary consumers or tertiary consumers? Explain your answer!
Third level or tertiary consumers; these organisms are more likely to have accumulated biotoxins because they eat higher on the food chain – therefore what they eat has accumulted trace toxins from the producers and primary consumers, concentrating these toxins in tertriary consumers.
Explain how the 10 percent rule limits population sizes in an ecosystem. Explain how the 10 percent rule contributes to bioaccumulation in ecosystems.
The 10 percent rule limits population sizes in an ecosystem, since only about 10 percent of energy is transferred between trophic levels. (The rest of the energy is lost as waste/heat.) Since only 10 percent of energy is transferred, each trophic level has about 1/10th the population size of the previous level.
Since organisms higher on the food chain have to eat a large number of prey (that have eaten large numbers of prey, etc.) toxins tend to accumulate at higher trophic levels.
What is sampling?
Sampling is estimating a population’s
size by counting a number of organisms
in a given area, then using that number
to estimate the total number of organisms.
You need to estimate the number of oak trees in Rock Creek Park. Which of the following methods would NOT work?
Mark and release.
C. Mark and release.
Describe the effect that an increased number of moose would have on the number of songbirds in the following food web:
Hawks Coyotes Songbirds
PRIMARY Moose Elk Deer Beaver Insects Rabbit
Moose eat willows, which serve as food for insects. More moose means fewer willows, fewer insects and fewer songbirds. Songbirds also use willows as nesting sites, so decreasing the number of willows also will directly effect the songbird populations.
In the graph below, what can we conclude about the influence of the predator population on the prey population? About the influence of the prey population on predator population?
You are tasked with counting the number of people in the D.C. metropolitan area. Describe TWO methods you could use to do this and the benefits and drawbacks of each.
Census and sampling. The census could be difficult because of frequent immigration to and emigration from the region. In addition, there may be certain populations (those without fixed addresses, illegal immigrants) who cannot be counted easily. The benefit is that you would theoretically count everyone. Sampling could be difficult because of variable population densities and the same reasons as above. The benefit is that it would take less time and be less expensive than taking a census.
What are nitrates and phosphates?
Nutrients from fertilizers that can run-off into local bodies of water and contribute to nutrient pollution and dead zones.
What is a source of dissolved oxygen in water?
Both A and D.
D. Both turbulence and
What are impervious surfaces? How do impervious surfaces connect to human populations and land use? To nonpoint pollution?
Impervious surfaces are surfaces that cannot absorb rainwater. Areas with high population tend to be highly developed and have a higher percentage of impervious surfaces (paved sidewalks and roads, roofs). Runoff from these surfaces often carries various pollutants that are left on the surfaces. Pollution that cannot be attributed to one cause is called nonpoint pollution.
High nutrient levels in water can lead to high levels of algae growing. What are some of the negative consequences of such an algae bloom?
Algae produces dissolved oxygen, but when
it dies decomposers consume more dissolved
oxygen than the algae produced, leading
to “dead zones” in rivers or the Bay. Algae,
dead or alive, can also block light to under-
water vegetation, thereby lowering oxygen
produced by photosynthesis.
You need to establish whether a river system is healthy. Describe what tests you could do to ascertain its health and what results you would expect from these tests were the river system healthy.
Test for: Dissolved oxygen, pH, temperature, nutrient levels (nitrates and phosphates), light levels, health of fish, etc.
Healthy tests: high DO, neutral pH, lower temp. than surrounding land, low nutrient levels, high light levels, fish without tumors/stress reactions, etc.
What is mutualism?
The relationship between two organisms of different species (or two populations) where both benefit.
A disturbance clears an ecosystem. What are the first two stages of succession? What organisms are likely to move into the area?
Establishment phase and exclusion phase. Pioneer species such as grasses and small plants move into the area, or existing seeds sprout. During the exclusion phase, weedy, fast-growing species move in and out-compete the initial grasses for limiting factors such as water and light. Accompanying animals, such as insects and herbivores, move in as well.
Termites rely on protozoans (single-celled organisms) living in their guts to help them digest cellulose, a carbohydrate found in wood. In return, the protozoan obtains a host and nutrients. Is this mutualism, commensalism or parasitism? How do you know?
Mutualism, because both species benefit from the relationship.
Mount Saint Helens, in the Cascade mountains, is an active volcano that erupted in 1980. What kind of succession would the local ecosystem have to undergo in order to be restored? Explain your answer.
Both primary and secondary succession would have to occur. Lava would coat the area in bare rock surface that would have to be processed back into soil. Areas that were covered in volcanic ash (different from lava) or otherwise cleared without removing/covering soil would undergo secondary succession.
Coral have symbionts (organisms living in them) called zooxanthallae, which perform photosynthesis. Speculate on whether you believe this is a parasitic, commensal, or mutualistic relationship and explain why.
The zoozanthallae are algae that photosynthesize. While the coral benefit from the sugars provided by the algae, it is unclear whether the algae obtain any benefit from this relationship, and is perhaps harmed by it. Therefore, it is unclear whether the relationship is mutualistic, commensal or parasitic, with the coral exploiting the algae.
What is carrying capacity?
The number of organisms of one species that an environment can support without degrading its resources.
In which type of growth does carrying carrying capacity play a role? What are some factors that cause population growth to stay around carrying capacity?
Logistic growth. Factors include limited
Biotic and abiotic resources such as prey,
competition, space, water, etc.
Intraspecific competition is within a species; interspecific competition is between species.
Abiotic resources are resources that have never lived (water, sunlight, etc.); biotic factors are living (competition, predation, food supplies, nesting sites/habitats in trees, etc.)
Density-dependent factors tend to be biotic (competition, etc., or limiting abiotic resources – plants competing over sunlight, water, etc.); density-independent factors tend to be natural disasters or other events that limit populations regardless of numbers.
Answers will vary.
Describe and explain the kind of population growth pictured below.
Populations grow exponentially until they reach carrying capacity, which shows the effect of limiting factors on the population. Once the population exceeds carrying capacity, limiting resources such as food, space, water, light, etc., will become scare and therefore the population will have a higher death than birth rate, decreasing it to below carrying capacity, upon which those resources become more available, allowing the population to once again increase.
Has the human population reached carrying capacity? Justify your answer in at least a paragraph. Your answer should include a definition of carrying capacity and an explanation of factors that could limit human population growth.
Carrying capacity: The maximum number of organisms in a population an ecosystem can support without degrading its resources.
Limiting factors: Space, food supply (agriculture, fishing, etc.), fossil fuels, clean water, etc.
Answers will vary.