Trophic Cascades
This term describes the process by which predators in a food web indirectly affect lower trophic levels.
Trophic Cascade
Define density-dependent factors in population ecology
competition, predation, diseases
Define density-independent factors in population ecology
Density-independent factors regulate the population without considering its density
Define a food web and distinguish it from a food chain
A food web is a diagram that links all of the food chains within an ecosystem. A food chain is a diagram showing the transfer of energy by eating or being eaten by an organism.
Define a food chain and provide an example from a terrestrial ecosystem
A food chain is a diagram showing the transfer of energy by eating or being eaten by an organism. Example: grass -> grasshopper -> lizard -> hawk
Give an example of a trophic cascade in a terrestrial ecosystem
Wolves being added to decrease the deer population at the Grand Canyon National Park
Give an example of a density-dependent factor that can regulate population size
predation
Give an example of a density-independent factor that can influence population size
Natural disaster, weather
Describe the significance of keystone species in maintaining stability in food webs
Keystone species maintain an ecosystem, without them an ecosystem would collapse
Explain the transfer of energy between trophic levels in a food chain
Only 10% of energy is gained from one trophic level to the next. For example, a hawk will only gain 10% of the energy stored in a lizard.
How do trophic cascades influence the abundance of plant species in an ecosystem
If a predator that eats primary consumers is added to an ecosystem, it would allow those plant species to grow more abundant
How do density-dependent factors contribute to population stability
They can increase or decrease population size as needed
How do density-independent factors differ from density-dependent factors in their effects on populations
Density-independent factors do not consider the density of a population while density-dependent factors do
How does energy flow through a food web differ at each trophic level
The energy gained as the trophic levels go up decrease, as energy is reduced 10%
How does the loss of one trophic level affect the stability of a food chain
The loss of one trophic level could make a food chain unstable, causing a species to increase while decreasing another, or vise versa
Explain the implications of altered trophic cascades on biodiversity
Altered trophic cascades could increase or decrease the population of a species in an ecosystem
Discuss the concept of carrying capacity in relation to density-dependent factors
Density-dependent factors can keep a population from exceeding the carrying capacity of an area
Discuss the role of natural disasters as density-independent factors in population dynamics
Natural disasters can increase the death rate of a population, despite the population size before the disaster struck
Explain the concept of ecological efficiency in food webs
Ecological efficiency in food webs is the transfer of energy from one trophic level to the next
Discuss the role of decomposers in recycling nutrients within food chains
Decomposers break down dead/unused material into simple inorganic material. They recycle nutrients into the soil or oceans for use by plants and other producers
Describe the role of keystone species in trophic cascades
Keystone species help define an ecosystem as a whole. If it was removed it would cause drastic changed within an ecosystem.
Explain the impact of disease outbreaks as density-dependent factors on populations
The spread of diseases can decrease the population of a species, which could affect the predators of that species and cause a whole affect from there on
Explain how climate change can act as a density-independent factor affecting populations
Climate change can affect many species in an area, creating an environment that is too cold or warm for the living conditions of certain species. For example, climate change can create an environment that has heat too extreme for the plant to grow successfully.
Discuss the impact of invasive species on native food webs
Invasive species could interrupt the developed food webs in an ecosystem, so it could cause changes in the population of species, etc
Analyze the implications of biomagnification in food chains
Biomagnification is a process causing the concentration of a substance to increase at higher levels of the food chain. If a body of water becomes contaminated and an animal consumes it, a predator or that animal could take in some of the toxicness from that animal and so on.