Energy Flow in Ecosystems

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Questions and Answers

What does a pyramid of biomass illustrate in an ecosystem?

The types of species present

The relative amount of living organic matter at each trophic level (correct)

The total number of organisms

The energy available at each level

What is the percentage of energy available from one trophic level to the next?

50%

10% (correct)

20%

In most ecosystems, how does the pyramid of numbers usually relate to the pyramid of biomass?

The pyramid of numbers is inverted

They are the same shape (correct)

The pyramid of numbers is larger

They are completely unrelated

Why might a pyramid of numbers be inverted in some ecosystems?

Consumers are much smaller than the organisms they feed upon Signup and view all the answers

What primarily determines the amount of biomass a given trophic level can support?

The amount of energy available Signup and view all the answers

What happens to energy stored in body tissues when one organism eats another?

Energy moves from the eaten to the eater Signup and view all the answers

How does energy flow through ecosystems?

In a one-way stream from producers to consumers Signup and view all the answers

What defines a food chain?

A series of steps in which organisms transfer energy by eating and being eaten Signup and view all the answers

In the food chain example from the Everglades, who is the top carnivore?

Alligator Signup and view all the answers

What is a characteristic of a food web?

It includes multiple food chains and their interactions Signup and view all the answers

Which of the following accurately describes primary producers in aquatic food chains?

They can be a mix of floating and attached algae Signup and view all the answers

Why is the food web a more accurate representation of ecosystems than a food chain?

It accounts for the numerous dietary options available to species Signup and view all the answers

How many steps are involved in the food chain presented in the Everglades example?

Four Signup and view all the answers

What does a pyramid of energy indicate about energy transfer between trophic levels?

About 10% of the energy is transferred to the next level. Signup and view all the answers

What type of ecological pyramid illustrates the amount of living organic matter at each trophic level?

Pyramid of biomass Signup and view all the answers

Why are there typically a limited number of trophic levels in a food chain?

Energy transfer efficiency is low between levels. Signup and view all the answers

Which statement accurately describes a pyramid of numbers?

It represents the relative number of individual organisms at each trophic level. Signup and view all the answers

What are primary producers in an ecosystem?

Organisms that convert solar energy into chemical energy. Signup and view all the answers

What happens to most of the energy that organisms acquire?

It is released as heat. Signup and view all the answers

Which ecological pyramid would you consult to understand the distribution of energy in a food web?

Pyramid of energy Signup and view all the answers

What role do decomposers play in an ecosystem?

They convert dead material into detritus. Signup and view all the answers

What percentage of energy from one trophic level is typically available to the next level?

10% Signup and view all the answers

How do detritivores fit into the food web?

They feed on detritus and contribute to the food web. Signup and view all the answers

What is the main distinction between a food chain and a food web?

A food chain is linear, while a food web is a complex network. Signup and view all the answers

What happens to nutrients when organisms die, and decomposers are present?

Nutrients are released for reuse by other organisms. Signup and view all the answers

What can occur following a disturbance in a food web?

Dependence on a keystone species can amplify impacts. Signup and view all the answers

How would a significant drop in krill populations affect aquatic food webs?

It would cause reductions in the populations of dependent predators. Signup and view all the answers

What do ecological pyramids illustrate?

The energy flow and trophic levels within a community. Signup and view all the answers

What might result from nutrients remaining locked in dead organisms?

Decreased fertility and productivity in the ecosystem. Signup and view all the answers

Study Notes

Energy Flow

Energy flows through an ecosystem in a one-way stream, from producers to various consumers.
Food chains are a series of organisms that transfer energy by eating and being eaten.
Each step in a food chain is called a trophic level.
Primary producers make up the first trophic level.

Food Chains & Food Webs

An Everglades food chain example: Phytoplankton and attached algae are eaten by flagfish, which are eaten by largemouth bass, which are eaten by anhinga, which may be eaten by an alligator.
Food webs are networks of feeding interactions that link all food chains in an ecosystem.
Detritus pathway: Decomposers convert dead material to detritus, which is eaten by detritivores, such as crayfish, grass shrimp, and worms.
Decomposers break down dead and decaying matter into forms that can be reused by organisms.
Disturbances to food webs can have dramatic effects.

Trophic Levels & Ecological Pyramids

Ecological pyramids show the relative amount of energy or matter contained within each trophic level.
There are three types of ecological pyramids: pyramids of energy, pyramids of biomass, and pyramids of numbers.

Pyramids of Energy

Only a small portion of energy that passes through a given trophic level is stored in the bodies of organisms at the next level.
Organisms expend much of the energy they acquire on life processes, such as respiration, movement, growth, and reproduction.
On average, about 10 percent of the energy available within one trophic level is transferred to the next trophic level.

Pyramids of Biomass & Numbers

Biomass is the total amount of living tissue within a given trophic level.
A pyramid of biomass illustrates the relative amount of living organic matter at each trophic level.
A pyramid of numbers shows the relative number of individual organisms at each trophic level.
The shape of the pyramid of numbers can be inverted, especially when small organisms are numerous compared to larger ones.

Review: Difference Between Food Chains and Food Webs

A food chain is a single pathway of energy transfer through feeding relationships.
A food web is a complex network that shows all possible feeding relationships in an ecosystem, linking multiple food chains together.

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Description

Explore the dynamics of energy flow in ecosystems through food chains and food webs. This quiz covers trophic levels, primary producers, and the importance of decomposers in an ecological context. Understand how disturbances can impact these intricate networks.