Flashcards in Exam Four Deck (71):
a community of organisms and the physical environment with which it interacts
T/F More than 10% of the sun's energy that reaches the earth's surface is used for photosynthesis.
False, *Less than 1%
The rest of the sun's energy... (3)
1. is the wrong wavelengths and is reflected or absorbed as heat energy
2. hits non photosynthetic surfaces and is reflected or absorbed as heat energy
3. is lost to plants because there is more energy than the plants can process at one time
Once energy has been captured by autotrophs through photosynthesis, how much energy is transferred to the next trophic level?
about 10% of energy
pertaining to nutrition" ex: autotrophic, heterotrophic, saprotrophic
Define trophic levels
the sequence of steps (from producers to primary, secondary, or tertiary consumers) through which energy and nutrients pass in a community of organisms
The rest of energy is lost due to... (3)
1. use of the energy in biomass to fuel metabolism (i.e. energy used to do work or is given off as heat)
2. death without being consumed by a predator. energy from this biomass supports the saprotroph community
3. failure to assimilate all consumed biomass. some biomass passes through as feces, which supplies energy to the saprotroph community
Saprotrophs can be consumed by predators and thus transfer energy to...
higher trophic levels
Ultimately, all energy is lost as heat due to...
metabolism (i.e. energy only passes through an ecosystem once)
Unlike energy, how often can nutrients cycle through ecosystems?
A basic description of a nutrient cycle can be broken into how many parts?
What is the nutrient cycle also know as?
The biogeochemical cycle
What are the four parts of the nutrient cycle? (4)
1. Movement of nutrients in their inorganic form
2. Movement of nutrients in their organic form
3. Movement of nutrients from the inorganic to the organic
4. Movement of nutrients from the organic back to the inorganic
What is the movement of nutrients in the inorganic form also known as?
The geochemical cycle
The movement of nutrients in their inorganic form happens in the... (3)
the atmosphere, lithosphere, and hydrosphere.
What are some sources of nutrient flux in the geochemical cycle? (5)
weathering, erosion, volcanoes, and deposition through rain, sedimentation, etc.
The movement of nutrients in their organic form is also known as?
The biochemical cycle
The movement of nutrients in their organic form is tightly linked to...
How do ecologists try to understand nutrient cycling?
By identifying and quantifying all the processes of nutrient gain and loss in an ecosystem (i.e. they create nutrient budgets)
What are the important variables in a nutrient budget of a terrestrial community? (4)
1. Atmospheric (air) inputs and outputs
2. Hydrospheric (water) inputs and outputs
3. Lithospheric (land) inputs and outputs
4. Human influence on nutrient cycling
Inputs to the biosphere from the air cause... (2)
1.Fixation of Nitrogen and Carbon by plants
2. Deposition of nutrients through wetfall and dryfall
The deposition of which nutrients are from aerosolized salt water?
Sodium, magnesium, chloride and sulfates
The deposition of which nutrients are from volcanoes, fires, and windstorms?
Calcium, potassium, and sulfates
Outputs to atmosphere from the biosphere cause... (3)
1. Release of Carbon during respiration
2. Release of nitrogen (often as ammonia gas) during decomposition and reduction reactions
3. Release of phosphorus, potassium, and sulfur in aerosols and volatile compounds (especially from plants)
Where are major nutrients inputed from water into the biosphere?
Floodplains and backwaters
Where in the biosphere are major nutrients lost from the hydrosphere? (2)
Lost in solution and in dead organic material
What does the lithosphere/land input into the biosphere? How?
Calcium, iron, magnesium, phosphorus and potassium from mechanical and chemical weathering of bedrock and soil.
Are there any major outputs to the lithosphere from the biosphere?
What does human activity input into the biosphere? (2)
1. Nitrogen and phosphorus from sewage disposal and fertilizers
2. Carbon dioxide and oxides of nitrogen and sulfur burning (especially of fossil fuels)
When are most major nutrients transferred from the biosphere related to human activity?
1. During harvesting of trees and agricultural crops
2. Into the atmosphere/hydrosphere due to disturbances (e.g. fire, plowing, logging).
Organisms live in an environment to which they must _________ in order to maintain life.
_________________ is a basic characteristic of life.
What are the major environmental variables to which life must respond? (5)
Environmental conditions, Resources, Competition, Predation, Disturbance
Define environmental conditions.
Factors that influence the functioning of an organism but are not consumed or used up by the organism.
What are these factors? (5)
Temperature, pH, Salinity, Physical forces, Toxic chemicals
Relative concentration of H+ and OH-.
What does pH affect? (3)
Osmoregulation, enzyme activity, gaseous exchange
The concentration of dissolved salts.
What does salinity affect?
Examples of physical forces? (3)
Wind, waves, currents
Anything that is consumed, competed for, by organisms.
Examples of resources? (5)
Energy, Mineral nutrients, Electron acceptor, Water, Space
Examples of energy? (3)
Photosynthesis, chemosynthesis, biotic food
Examples of mineral nutrients? (9)
N, P, S, K, Ca, Mg, Fe, Na, Cl
Electron acceptors are usually ________________.
What is the universal solvent?
An interaction between individuals that is brought about by a shared requirement for a limited resource and which ultimately leads to a reduction in the survival and/or reproduction of some of the individuals involved.
Consumption of one organism (the prey) by another organism (the predator) in which the prey is alive when the predator first attacks it. (Includes true predators, grazers, parasites, parasitoids).
A sudden (often unpredictable) change in environmental conditions or resource availability, which alters an organism's ability to survive in that location.
What are the responses of individuals to a dynamic environment? (4)
Behavioral, Physiological, Immune, Developmental
Define behavioral responses.
Any observable action or response of an organism to its environment.
T/F Every living organism has behavior.
Which systems are animal behavioral responses meditated through? (2)
Nervous and Endocrine (Hormone) Systems
Responses can vary from ______________ behavioral patterns to more __________________ behaviors.
relatively 'fixed'; variable 'plastic'
Examples of models of animal behaviors created by scientists? (3)
The ideal free distribution, Tit-for-tat (game theory), Optimal foraging theory
When and who created the ideal free distribution model?
When and who created the tit-for-tat (game theory) model?
What does the ideal free distribution predict?
How organisms should distribute themselves spatially in order to maximize food intake when food is limited.
The ideal free distribution is an oversimplification that ignores... (4)
Limited movement ability, Resources guarding, Social behavior, Predation
What does the tit-for-tat (game theory) predict?
How two individuals should interact with each other given the possibility that one individual could take advantage of the other.
Tit-for-tat (game theory) is an oversimplification that assumes... (4)
1. Individuals can recognize each other
2. There are many interactions between individuals
3. Individuals can respond based on previous interactions
4. The benefit of receiving must outweigh the cost of giving
What is the scientific process? (2)
Collecting data (observing), Creating descriptions of reality (models)
`What do models do? (2)
Make sense of available data and experimental results using natural laws, can be used to make predictions and guide the direction of future research
A scientific model is used as long as... (3)
Data is consistent with predictions of the model, no other model explains the data better, it provides a useful way of thinking about our universe
What does optimal foraging theory predict?
How long predators should spend at a patch (i.e. foraging site) before leaving it to look for another patch.
The optimal foraging theory is an oversimplification that assumes... (2)
1. Energy intake per unit time is the sole currency being optimized
2. Individuals have the capacity to evaluate overall rate or energy intake
What are the predictions of optimal foraging theory for when predators should switch patches? (3)
1. Stay-time in a patch should be greater in more productive patches than in less productive patches.
2. Stay-time in a patch should be greater in environments where travel-time between patches is greater.
3. Stay-time in a patch should be greater in environments that are less profitable (i.e. low average rate of energy gain).
Define physiological respones.
The internal physical and chemical responses of the body to a dynamic environment.
T/F Every living organisms has physiological responses.
Which systems are animal physiological responses meditated through? (2)
Nervous and Endocrine (Hormone) Systems