29 Questions
What is the primary purpose of ecological pyramids in showing the relative amounts of various parameters across trophic levels?
To show the efficiency of transfer from one trophic level to the next
What shape do pyramids of numbers typically take in an ecosystem?
The shape of an actual pyramid with the base being the broadest
What is the limitation of the ecological pyramid in terms of representing food webs?
It does not fully take into account food webs, as multiple species may occupy multiple trophic levels
What is not considered in any of the ecological pyramids, despite being an important part of ecosystems?
Saprophytes
What is the significance of the width of each bar in an ecological pyramid?
It should be proportional to the quantity being displayed
What is the limitation of the ecological pyramid in terms of representing the same species at different levels?
It does not consider the possibility of the existence of the same species at different levels
What is the main difference between a pyramid of biomass and a pyramid of numbers?
A pyramid of biomass shows the biomass at each trophic level, while a pyramid of numbers shows the population at each trophic level.
Why is the pyramid of biomass upright in most ecosystems, but inverted in ocean ecosystems?
In ocean ecosystems, the large number of zooplankton depends on a relatively smaller number of phytoplankton, resulting in an inverted pyramid.
What is the unit of measurement for biomass in a pyramid of biomass?
Grams per meter squared.
Why is the biomass of phytoplankton minimized at any particular point in time?
The phytoplankton are consumed rapidly by the primary consumers, minimizing their biomass.
What is the advantage of using biomass instead of population in a pyramid?
Biomass is a more reliable and quantitative measure of the ecosystem.
What are the primary factors that can disturb the process of primary succession in an area?
Fire, flooding, severe erosion, tree cutting, climate change, or other natural or human processes
What is the initial step in the process of primary succession in a newly created small pond?
An influx of sediments and nutrients in runoff from the surrounding land
What is the primary difference between primary and secondary succession?
Primary succession occurs in areas where no ecosystem previously existed, while secondary succession occurs in areas where an ecosystem has been disturbed or destroyed.
What is the result of the changes in vegetation during ecological succession?
Changes in food and shelter for various types of animals, leading to changes in the numbers and types of animals and decomposers.
What is an example of a habitat that may undergo secondary succession?
Abandoned farmland, burned or cut forests, heavily polluted streams, or land that has been flooded.
How quickly can new vegetation germinate in disturbed land following secondary succession?
Usually within a few weeks
What is the key difference between upright and inverted pyramids of numbers?
Upright pyramids of numbers occur when the number of organisms decreases at each trophic level, whereas inverted pyramids occur when the base of the pyramid consists of few organisms compared to the number of primary consumers.
How are pyramids of number constructed?
Data is obtained by counting organisms in a particular area, and each trophic level is drawn proportional to the number of individuals in that level.
What is a limitation of using pyramids of numbers?
Pyramids of numbers ignore the size of organisms, making it difficult to compare species of different sizes.
What is an advantage of using pyramids of numbers?
Pyramids of numbers are easy to construct and do not require harming or killing organisms.
In which ecosystem would you expect to find an inverted pyramid of numbers?
Temperate forests, where a few trees support a large number of primary consumers, such as insects.
What is biomass, in the context of ecological pyramids?
Biomass is the total dry mass of one animal or plant species in a food chain or food web.
What is the main advantage of the pyramid of biomass compared to the pyramid of numbers?
It is more reliable than the pyramid of numbers.
Why is it difficult to accurately represent an organism in a pyramid of biomass?
Because an organism may belong to more than one trophic level.
What is a key characteristic of pyramids of energy?
They are always upright, with energy decreasing at each trophic level.
Why is it necessary to remove water from organisms when measuring dry biomass?
To get an accurate measurement of biomass.
What is a disadvantage of pyramid of energy studies?
Collecting data can be difficult and complex.
What units are typically used to measure energy in pyramids of energy?
KJ (Kilojoules) or Kcal (older unit-Kilocalories) per m2 per year.
Study Notes
Types of Ecological Pyramids
- Ecological pyramids show the relative amounts of various parameters across trophic levels.
- There are three types: Pyramids of Numbers, Pyramids of Biomass, and Pyramids of Energy.
Pyramid of Numbers
- This type of ecological pyramid considers the number of organisms in each trophic level.
- The pyramid of numbers is usually upright except for some situations like that of the detritus food chain.
- Example: a typical grassland during the summer has an upright shape, with many plants and decreasing numbers of organisms at each trophic level.
Pyramid of Biomass
- Biomass is the total dry mass of one animal or plant species in a food chain or food web.
- A pyramid of biomass shows the biomass at each trophic level, rather than the population.
- Advantages: more reliable than pyramid of numbers; disadvantages: animals have to be killed to measure dry biomass.
Pyramid of Energy
- Pyramids of energy are always upright, since energy is lost at each trophic level.
- Units used are KJ (Kilojoules) or Kcal (older unit-Kilocalories) per m2 per year.
- Advantages: shows efficiency of conversions; disadvantages: collecting data can be difficult and complex, and some organisms are killed.
Ecological Succession
- There are two types: Primary Succession and Secondary Succession.
- Primary Succession occurs in an area where no ecosystem existed before (e.g., newly created small pond).
- Secondary Succession begins in an area where an ecosystem has been disturbed, removed, or destroyed, but some soil or bottom sediment remains.
- Both types of succession lead to changes in vegetation, affecting food and shelter for various types of animals and decomposers.
Learn about the concept of ecological pyramids, which display the relative amounts of parameters such as number of organisms, energy, and biomass across trophic levels. Understand the different types of pyramids, including upright and inverted ones, and how they relate to food chains and food webs.
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