Ecology Final Exam
What areas of the earth that came from Gondwana vs. Laurasia?
- Gondwana: South America, Antarctica, Africa, India - Laurasia: North America, Europe, Asia
Draw a graph that shows the usual pattern of rarity and commonness of different species in a community. Also, explain in words what this normal pattern is. Also, remember that there are two ways of showing this relationship- draw both.
- Graph 1: bar graph starting with tall bars and ending with short bars - Graph 2: Proportional abundance vs. Abundance rank (star at top, line goes down to the middle diagonally, then a line that goes straight horizontally) - Pattern: there are a lot more rare species than there are common species
On a figure of delta13C vs delta15N, draw the positions for plants, herbivores that feed on them, and the predators that feed on them. Also, explain why you see these differences in values.
- Graph: ~y-axis: delta13C ~x-axis: delta15N ~curve going diagonally upwards starting from 0 (order: Primary Producers -> Herbivores -> Omnivores -> Predators) - You see differences in values because of intake as you go up: as you increase in levels, you are intaking the nutrients of the previous levels.
What factors determine whether terrestrial ecosystems are strongly limited by nitrogen, versus P and K?
- Age of soil: ~ Older Soil: more limited by phosphorous and potassium, stuff that causes weathering ~Younger Soil: Nitrogen Build up
What do the terms alpha, beta, and gamma diversity mean?
- Alpha Diversity: Species richness, the species diversity at a local scale (local diversity) - Gamma Diversity: Species pool that is available to colonize a specific community - Beta Diversity: Species turnover between communities, regional diversity
What areas of the ocean have highest New Productivity Production? Also, what terrestrial ecosystems have the highest Net Productivity Production?
- Areas of the ocean with highest NPP: Coastal areas because of upwelling (which brings in more nutrients). Waves bring up the algae filled water to the land and makes the land high in nutrients. - Areas of terrestrial ecosystems with highest NPP: Tropics due to the wide variety of species
What is bioaccumulation? What are the characteristics of compounds that do vs. those that don't bioaccumulate? What are examples of toxic compounds that do and do not bioaccumulate?
- Bioaccumulation (same as Biomagnification): Toxins that accumulate in fatty lipids -> higher the trophic level, higher the bioaccumulation. Accumulation of a certain substance in a particular organism. - Characteristics: elements that are lipid/fat soluble get accumulated more - Examples: ~DO bioaccumulate: Mercury ~DON'T bioaccumulate: Lead
What is a biome? Within a single biome, do all differnt communities have the same dominant species?
- Biome: Contiguous áreas with similar climatic conditions on the earth, such as communities of plants, animals, and soil organism, and are often referred to as ecosystems (Ex: tundra, desert, etc.) - No, variation of species depends on scale of biome
What are the major ways in which N and C enter ecosystems, and the major ways that they are lost?
- C Enters: Being fixed, plant fixing carbon - C Leaves: Respiration - N Enters: Haberbaash, microbes fix nitrogen - N Leaves: De-nitrification, nitrogen gets turned into gas by bacteria
What causes ozone depletion? Why is ozone depletion generally thought to be a bad thing?
- Cause: The presence of chlorine containing source gases such as CFCs. It is also depleted by bromine chemicals, halons, carbon tetrachloride and hydroflurocarbons. - Why is it bad: Health effects
What are the major causes and locations of acid precipitation?
- Causes: Sox (coal, fossil fuel combustion), Nox (Pollution) - Location: Heavily industrialized locations: Europe, China, East America
What are the 3 general categories of explanations for tropical diversity that the text presents? What are their graphs?
- Diversification Rate: Graph: Both lines curving upwards starting from the same spot - Diversification Time: Graph: both lines curving upwards starting one from 0 and one from a bit further up - Productivity/Carrying Capacity: Graph: both lines curving upwards one starting from 0 and the other breaking out of the curve -one line is full the other is dotted
What are dominant species in a community? What are foundation species?
- Dominant Species: Species that are high in abundance and has large effects on other species - Foundation Species: (pretty much the same as dominant species & opposite of keystone species) Has large impact on it's community (also high abundance)
Is energy flow from plants to herbivores higher in aquatic or terrestrial ecosystems? What are three possible explanations for this difference?
- Energy flow is higher in aquatic ecosystems because: 1. Herbivores are constrained by predators 2. Defenses against herbivory 3. Chemical systems are more similar in aquatic ecosystems in terms of consumer & producer
What is potential evapotranspiration? What does it have to do with species diversity patterns?
- Evapotranspiration: estimate of energy - Potential Evapotranspiration: How much would evaporate from a certain amount of water. Related with species diversity because it correlates positively. More energy -> more species richness.
Let's say you are conducting a survey of the birds in Rock Mt. National Park. Each day you go out and spend about 14 hours watching and listening for birds. Draw a figure that shows how many different bird species you expect to have seen or heard, in total, as you have spent more and more days trying to find the species in this area. Finally, explain how the curve you drew relates to patterns of commonness and rarity within communities.
- Graph: (Number of species vs. Number of samples (time effort)) (Species accumulation curve) line starts low an curves upwards (hump facing up) - Explanation: At first you will see many different types of species, but as you spenf more time in the park, the number of different species you see will go down.
Define gross primary production, net primary production, community respiration, and net community production. How are these different quantities related?
- Gross Primary Production: Total input of carbon brought in - Net Primary Production: (Gross Primary Productivity) - (Respiration) - Net Community Production: (Gross Primary Production) - (Community Respiration) - Community Respiration: Energy transfers within an ecosystem: intake of oxygen and the release of carbon dioxide
Describe the contrast between the individualistic vs. the super-organism view of how communities are organized. Name a clear prediction that each makes about how sets of species should change across time or space. Finally, which prediction is apparently more correct, and what are two examples of data sets that support this theory?
- Individualistic: Each species has it's own tolerance - Super-Organism: Strongly interact/coexist with one another to the point where they cannot live without each other - Idea: Species are strongly interacting/co-evolving with one another/together - Prediction: They would form blocks
What generates anthropogenic nitrogen deposition? What kinds of places have higher levels of deposition, and what are some of the ecological effects to this?
- Industrialization, fertilization of agriculture, and combustion (burning of fossil fuels & fossil forests) generate anthropogenic nitrogen deposition - Urban areas have higher levels of deposition - Stimulates growth, increases levels of carbon, decreases soil fertility
Which terrestrial ecosystems have the largest living biomass? Which have the largest non-living biomass?
- Largest Living Biomass: Tropical areas, terrestrial ecosystems - Largest Non-living Biomass: Arctic Tundra, Tidra
Draw two different species number vs. habitat area figures. One with each scale logged, and one with raw (unlogged) numbers
- Logged: straight, diagonal line going upwards and starting from 0 - Unlogged: curve with hump upwards going up
What are some of the most common limiting resources for marine NPP? What about terrestrial tropical NPP?
- Marine: Nitrogen, Sunlight, Iron - Terrestrial: Phosphorous, Potassium, Calcium, Water, Light, Temperature
What is nutrient spiraling and where does it occur?
- Nutrient Spiraling: how nutrients flow from the top of a stream to the bottom. Elements get taken up by things like algae, they are then assimilated(molecule travels around for a while), molecule gets released, elements spiral down. (shows vector: direction transformation)
Primary vs. Secondary Succession
- Primary: No material left over (more predictable) - Secondary: Some material left over
Explain why large salmon runs are thought to increase the stream and forest productivity. Also, what do bears do to increase these effects?
- Salmon: high in nitrogen & phosphorous. Energy gets lost (washed down the stream), when salmon migrate-> nutrients get brought back up, salmon die (bodies high in nitrogen), dead bodies create nutrient influx. - Bears: eat salmon bodies and poop out remains that are high in nitrogen, spreading nitrogen throughout the forest.
What is the difference between species richness, species diversity and species evenness?
- Species Richness: The number of different species represented in an ecological community, landscape or region - Species Diversity: The effective number of different species that are represented in a collection of individuals (in a dataset) - Species Evenness: How close in numbers each species is in an environment are. Mathematically, it is defined as a diversity index, a measure of biodiversity which quantifies how equal the community is numerically.
Be able to describe two examples of succession, including what some of the dominant species are in early vs. late succession for each
- Succession: The observed process of change in the species structure of an ecological community over time. - Primary Succession: New substrate devoid of vegetation and usually lacking soil, such as a lava flow or area left from retreated glacier, is deposited - 2 Examples: 1. Glacier: start with mosses & carbon turns to soil & make tree's 2. Forest Fire - Secondary Succession: Changes that occur as a previously damaged ecosystem recovers. - 2 Examples: 1. Salt Marsh 2. Volcano
What are the major natural resources of P and K in terrestrial ecosystems? What are the major pools of these elements on earth?
- The major natural resources come through the weathering of rocks and other minerals - P: Canada, Russia, Northern Hemisphere - K: Western Sahara, China, South Africa, Southern Hemisphere
Explain how and why tundra ecosystems are expected to change their balance of CO2 production and generation with global warming (and increasing atmospheric CO2). Also, summarize whether these changes have been seen to date.
- Tundra ecosystems are expected to change their balance of CO2 due to tundra thaws -> permafrost holding biomass releases CO2 into the atmosphere, which increases the overall temperature which causes the permafrost to thaw and melt.
What is upwelling, where does it occur, and why is it important?
- Upwelling: nutrients at the bottom of the ocean come up to the top, replenishing nutrients - Where: along coastal regions - Why is it important: It is where the bulk of the net primary productivity occurs -> important for fisheries and ocean biodiversity in general
What is the equation that describes the species area curve?
-S = C*A^z or ln(s) = ln(c) + Z (ln(a)) -S: Species Richness -A: Area -C: y- intercept -Z: Slope (on graph)
Two examples of succession
1. Glacier Bay's (Primary) 2. Rocky tital area (Secondary) 3. Salt Marsh (Secondary)
What are the 6 different explanations for why there are more species in the tropics?
1. High productivity 2. High energy 3. More time 4. Life is hard 5. Stable climates 6. Higher habitat heterogeneity
What are three of the major perturbations to atmospheric cycles and processes that humans have caused? In one or two sentences, explain what each of these issues involves, and whether the problem is stable, getting worse, or getting better.
1. Increased CO2 in the atmosphere: Getting worse 2. Nitrogen: Getting worse 3. Ozone: - Troposphere: forms through combustion of fossil fuels, irritant for lungs (getting better) - Stratosphere: GOOD! reflecting of UVV rays which degrade DNA & cause cancer
What are two of the theories for why different ecosystems have differing numbers of trophic levels?
1. More energy -> more trophic levels lead to more production and higher carrying capacity 2. Greater ecosystem size -> greater heterogeneity
What are three different examples of communities that show the intermediate disturbance effect?
1. Porcupines 2. Grizzly Bears 3. Logging in the tropics
What are the types of ecosystem stability?
1. Resistance: ability for a community to not change 2. Resilience: ability to restore yourself to your previous state. "Bounce Back"
What are 3 ideas of how to reduce CO2 in the atmosphere?
1. Sinking tree's (with iron pumped inside of them to weigh them down) 2. Iron Shaving -> algae grows 3. Liquified CO2 deposits in the ocean -> trap it and pump it in to the ocean/land 4. Reducing fossil fuel emissions
Beyond global warming, what are two ecological effects of increased CO2? Explain the mechanisms for both.
1. Stimulating plant growth: Negative effects on grass around plant growth, alters community compositions (in both terrestrial and aquatic communities). Alters the standing biomass. 2. Ocean Acidification: Carbon can't bond with calcium. Creates excess of one molecule over another. Does not dissolve coral -> changes carbonate reactions in the ocean, coral cannot get the carbonate that in needs.
What is secondary production?
All biomass that is dependent on primary production for energy. (commonly for Heterotrophs -> everyone that isn't an autotroph)
Explain how the herbivore biomass in open ocean ecosystems can be larger than the plant biomass
Because herbivores have higher turnover rates. The energy transfer has to be the same. Primary Production is dominated by little organisms that only live for a few short days. (Image: two circles: sp is on larger circle on top, pp is on smaller circle on bottom)
Explain why recycling is not a very effective way to fix the problem of increasing metal releases into the bio-sphere. Also, explain the concern with these releases
Because you loose a little but of substance every time you recycle something. It matters because a lot of these things are toxic and they bioaccumulate.
The shannon index is bounded somewhere between two different numbers that depend on the total number of species seen in a survey. What are these numbers?
Between 1 and S
What are Detritivores?
Critters that eat dead stuff. Ex: Rollie Pollies
Do ectotherms or endotherms have higher production efficiency? Why?
Ectotherms have higher production efficiency because endotherms produce their own heat so most of what they produce gets turned into heat.
Do ectotherms or endotherms have higher productivity efficiency? Why?
Ectotherms have higher productivity efficiency because they don't loose energy when they produce heat because they use outside sources to produce it.
What is an example of an ecosystem that is not based on energy from photosynthesis? How?
Example: Hydrothermal vents, they get their thermal heat (energy) from the earth's core of molten iron
What have humans done to the global cycling of heavy metals?
Humans have increased the release rate of most metals
The intermediate disturbance hypothesis predicts what? There are two ways that this idea helps to account for patterns in species richness as a function of disturbance. Why do you see the overall pattern predicted by the IDH? Also, what kinds of species are most common soon after disturbance vs. long after the most recent disturbance?
I.D.H.: How certain disturbances effect species diversity at intermediate levels -> most species diversity/richness. Balances colonization with competitive exclusion. 1. Collective time -> good competitors 2. Creates a mosaic od time since burned - Graph: hill shaped
What is the Intermediate Disturbance Hypothesis?
IDH states that local species diversity is maximized when ecological disturbance is neither too rare nor too frequent. According to IDH theory, at intermediate levels of disturbance, diversity is thus maximized because both competitive K-selected and opportunistic r-selected species can coexist.
Does higher biodiversity generally lead to increased or decreased productive and stability of ecosystems? What are the three possible explanations for the effects of biodiversity on stability and productivity?
Increased, because: 1. Complementarity (facilitation): species need the help of other species to survive 2. Luck of the draw: some species will do well, while other will not. (if you have a lot of species) 3. Redundancy: having a bunch of species doing the same task -> some will succeed, others won't
Is most NPP consumed by higher trophic levels? If not, what does it become?
No, because NPP become detritus (waste or debris of any kind)
What time of the year do noctule bats eat birds? What is the information used to determine the timing and extent of bat feeding on birds?
Noctule bats eat birds in the fall because they have more young during that time.
What is nitrification?
Oxidation of ammonia compound into nitric acid (into a nitrate)
What are the most common controls of NPP in lakes?
Phosphorous & Nitrogen
What does autochthorous mean?
Source of energy that originates inside of the system
What does allochthonous mean?
Source of energy that originates outside of the system
Briefly explain important aspects of the movement behavior of: blue fun tuna; wandering albatross, barred godwits, and great white sharks.
Telemetry is being used as a resource to mark migration patterns
What is mineralization?
The chemical conversion of organic matter into inorganic matter
If condors mostly eat dead deer, the mountain lions mostly eat deer they kill themselves, would you expect them to have similar or different stable isotope values?
Two animals feeding on the same resource will have the same isotopic signature.
What is "faunal relaxation" and when will it occur?
When plants begin to die off due to habitat loss -> species richness decrease
What is an "indirect interaction"?
When the relationship between two species is mediated by a third party -> indirect effect