Pirâmides Ecológicas - Ecologia | Biologia com Samuel Cunha

Summary

In this video lesson, the concept of ecological pyramids is explored, focusing on three types: the pyramid of numbers, biomass, and energy. The pyramid of numbers illustrates the number of individuals in each trophic level, while the pyramid of biomass shows the mass of organisms at each level. The pyramid of energy highlights how energy flows unidirectionally through the ecosystem, with producers capturing the most energy from the sun. The video explains these pyramids in simple terms, using examples from both terrestrial and aquatic ecosystems to demonstrate how energy and matter are transferred through food chains.

Takeaways

• 😀 Ecological pyramids graphically represent the flow of energy and matter in a food chain.
• 😀 There are three types of ecological pyramids: pyramid of numbers, pyramid of biomass, and pyramid of energy.
• 😀 The pyramid of numbers indicates the number of individuals at each trophic level in a food chain.
• 😀 A pyramid of numbers can be inverted, as seen in examples where the base starts smaller than the top, like with trees and insects.
• 😀 The pyramid of biomass measures the dry mass of organisms in each trophic level, typically in grams or kilograms per square meter.
• 😀 In aquatic environments, the pyramid of biomass can be inverted due to the rapid reproduction of phytoplankton, which have less biomass than primary consumers.
• 😀 The pyramid of energy is crucial as it shows the amount of energy stored in organisms at each trophic level, and energy only flows in one direction.
• 😀 Energy in an ecosystem comes from the sun and cannot be recycled, it is transformed but never created or destroyed, according to the laws of thermodynamics.
• 😀 Plants, as producers, capture energy from the sun, but only a small portion is stored; most is used for growth and survival.
• 😀 The pyramid of energy cannot be inverted because energy is lost at each trophic level due to processes like respiration.
• 😀 The energy that we consume through food (like bread, rice, or meat) ultimately comes from the sun, demonstrating the importance of energy flow in ecosystems.

Q & A

What are the three types of ecological pyramids discussed in the transcript?

The three types of ecological pyramids discussed are the Pyramid of Numbers, the Pyramid of Biomass, and the Pyramid of Energy.

What does the Pyramid of Numbers represent?

The Pyramid of Numbers represents the number of individuals in each trophic level within an ecosystem.

Can the Pyramid of Numbers be inverted? If so, what does this mean?

Yes, the Pyramid of Numbers can be inverted. This occurs when the number of individuals decreases as you move up the trophic levels, which can happen in certain ecosystems like when a tree supports many insects, and those insects support a few birds.

What is the Pyramid of Biomass, and how is it measured?

The Pyramid of Biomass indicates the body mass of organisms at each trophic level. It is typically measured as dry mass, which is obtained by drying the organisms to remove water content and then measuring their mass.

Can the Pyramid of Biomass be inverted? In which environments is this commonly observed?

Yes, the Pyramid of Biomass can be inverted in aquatic environments, such as oceans or lakes, where primary producers like phytoplankton may have a smaller biomass than primary consumers like zooplankton.

What is the difference between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP)?

Gross Primary Productivity (GPP) is the total energy that plants capture from the sun through photosynthesis. Net Primary Productivity (NPP) is the energy that remains after plants use some of it for their own survival through processes like respiration. NPP is what is available to the next trophic level.

Why is the Pyramid of Energy considered the most important of the three pyramids?

The Pyramid of Energy is considered the most important because it represents the flow of energy through an ecosystem, which is always unidirectional. Energy is never recycled, and it is lost at each trophic level, primarily as heat, following the laws of thermodynamics.

How is energy measured in the Pyramid of Energy?

Energy in the Pyramid of Energy is typically measured in units like kilocalories per square meter per year (kcal/m²/year), or sometimes in grams or kilograms per square meter per year, depending on the study.

Why do we observe fewer herbivores than plants in most ecosystems?

We observe fewer herbivores than plants because the amount of energy available to herbivores is limited by the energy stored in plants. If there were too many herbivores, there would not be enough energy to support them, as the energy flow from producers to consumers is finite.

How does energy flow in an ecosystem according to the transcript?

Energy flows in one direction in an ecosystem, from producers (such as plants) to primary consumers (herbivores) and then to higher trophic levels. This flow is powered by the sun, which is the ultimate source of energy for the ecosystem.