BIO 201 MODULE 5, HOW ESSENTIAL NUTRIENTS
MOVE THROUGH THE ECOSYSTEM – ENERGY AND
MATTER TRANSFER COMPREHENSIVE STUDY
GUIDE & REVISION NOTES 2026
5.1 Energy and Matter Transfer
Learning Objectives
Define ecosystems.
Describe how energy and matter transfer between trophic levels in a food
web.
5.1.A Defining Ecosystem Ecology
DDT and Bald Eagles
The Channel Islands off the coast of southern California used to be a nesting
ground for bald eagles until hunting and a pesticide called DDT eliminated them
from the islands during the 1980s.
DDT
Pesticide used to kill insects.
Extremely harmful to the environment.
Banned in 1970.
A production plant in Los Angeles dumped DDT waste into the ocean near the
Channel Islands.
DDT caused eggshell thinning in bald eagles, preventing them from producing
viable offspring.
Module 5: How Essential Nutrients Move Through the Ecosystem 1
, Important Question
Even after bald eagles were reintroduced in 1987, they still could not produce
viable eggs because DDT remained in the ocean.
Question posed by the lecture:
Why would DDT in the ocean affect bald eagle eggs when bald eagles are
terrestrial?
(The answer comes later through nutrient movement and biomagnification.)
Levels of Ecological Organization
Individual
One single living organism.
Population
All members of one species living in the same environment.
Community
All populations living in the same environment.
Ecosystem
The community of interacting organisms and their environment.
Components of an Ecosystem
An ecosystem includes both:
Abiotic Factors
Nonliving parts of the environment that affect organisms.
Examples:
Environmental toxins
Module 5: How Essential Nutrients Move Through the Ecosystem 2
, Temperature
Phoenix heat
Rivers
Streams
Nutrients
Biotic Factors
Living organisms that affect other organisms.
Examples:
Competition
Predators
Parasites
Ecosystem Ecology
Ecosystem ecology is the study of interactions between:
Abiotic components
Biotic components
of an environment.
Just as biotic factors influence an organism' s niche, abiotic factors do as well.
Examples:
Temperature
Nutrient availability
Example:
Plants requiring nitrogen may be unable to survive in nitrogen-poor soils.
Quiz Questions
Module 5: How Essential Nutrients Move Through the Ecosystem 3
, Question 1
Which are abiotic factors?
✔ Environmental toxins
✔ Phoenix heat
✔ Rivers and
streams NOT:
Competition
Predators
Question 2
Which are biotic factors?
✔ Competition
✔ Parasites
✔ Predators
NOT:
Environmental toxins
Sunshine
5.1.B Energy and Matter Transfer Between
Trophic Levels
One of the most important nutrients is carbon.
Why carbon is important
Carbon:
Has four unpaired electrons.
Forms four covalent bonds.
Is extremely versatile.
Module 5: How Essential Nutrients Move Through the Ecosystem 4
MOVE THROUGH THE ECOSYSTEM – ENERGY AND
MATTER TRANSFER COMPREHENSIVE STUDY
GUIDE & REVISION NOTES 2026
5.1 Energy and Matter Transfer
Learning Objectives
Define ecosystems.
Describe how energy and matter transfer between trophic levels in a food
web.
5.1.A Defining Ecosystem Ecology
DDT and Bald Eagles
The Channel Islands off the coast of southern California used to be a nesting
ground for bald eagles until hunting and a pesticide called DDT eliminated them
from the islands during the 1980s.
DDT
Pesticide used to kill insects.
Extremely harmful to the environment.
Banned in 1970.
A production plant in Los Angeles dumped DDT waste into the ocean near the
Channel Islands.
DDT caused eggshell thinning in bald eagles, preventing them from producing
viable offspring.
Module 5: How Essential Nutrients Move Through the Ecosystem 1
, Important Question
Even after bald eagles were reintroduced in 1987, they still could not produce
viable eggs because DDT remained in the ocean.
Question posed by the lecture:
Why would DDT in the ocean affect bald eagle eggs when bald eagles are
terrestrial?
(The answer comes later through nutrient movement and biomagnification.)
Levels of Ecological Organization
Individual
One single living organism.
Population
All members of one species living in the same environment.
Community
All populations living in the same environment.
Ecosystem
The community of interacting organisms and their environment.
Components of an Ecosystem
An ecosystem includes both:
Abiotic Factors
Nonliving parts of the environment that affect organisms.
Examples:
Environmental toxins
Module 5: How Essential Nutrients Move Through the Ecosystem 2
, Temperature
Phoenix heat
Rivers
Streams
Nutrients
Biotic Factors
Living organisms that affect other organisms.
Examples:
Competition
Predators
Parasites
Ecosystem Ecology
Ecosystem ecology is the study of interactions between:
Abiotic components
Biotic components
of an environment.
Just as biotic factors influence an organism' s niche, abiotic factors do as well.
Examples:
Temperature
Nutrient availability
Example:
Plants requiring nitrogen may be unable to survive in nitrogen-poor soils.
Quiz Questions
Module 5: How Essential Nutrients Move Through the Ecosystem 3
, Question 1
Which are abiotic factors?
✔ Environmental toxins
✔ Phoenix heat
✔ Rivers and
streams NOT:
Competition
Predators
Question 2
Which are biotic factors?
✔ Competition
✔ Parasites
✔ Predators
NOT:
Environmental toxins
Sunshine
5.1.B Energy and Matter Transfer Between
Trophic Levels
One of the most important nutrients is carbon.
Why carbon is important
Carbon:
Has four unpaired electrons.
Forms four covalent bonds.
Is extremely versatile.
Module 5: How Essential Nutrients Move Through the Ecosystem 4
