Ecosystems and Energy

Chapter 3

“In the end, we will conserve only what we love, we will love only what we understand, we will understand only what we are

taught.”

-Baba Dioum

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Chapter 3 Overview

Ecology

Feeding Relationships

The Energy of Life

The Flow of Energy Through Ecosystems

What is Ecology?

Ecology –

study of the interactions among organisms, and between organisms (biotic) and their abiotic (non-living) environment.

What is Ecology?

Levels of Biological Organization

What is Ecology?

Ecological Levels of Organization:

Population

What is Ecology?

Ecological Levels of Organization:

Community

What is Ecology?

Ecological Levels of Organization:

Ecosystem

CO2

What is Ecology?

Biomes (Landscape ) –

encompasses larger area and several ecosystems

Biosphere –

the whole earth

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THE STRUCTURE OF ECOSYSTEMS

The parts that fit togetherPhysical and chemical factors

Feeding relationships

Species interactions

Climate

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How Ecosystems Are Formed

Abiotic

Plants

Animals

(moisture and temperature)

(+ moisture = forest)(temperature = forest type)

(lynx or bobcat)

predict

predict

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Inorganic and Organic

Inorganic

Oxygen

Carbon dioxide

Nitrogen

Water

pH

Organic

All living things

Products of living things

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Inorganic and Organic

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Moisture and Temperature

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Abiotic Factors

The physical and chemical part of an ecosystem.

Conditions: Vary in time and space.No Competition

Temperature

Wind

pH

Salinity

Fire

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Abiotic Factors (cont.)

Resources: Consumed by organisms.Competition

Water

Chemical nutrients

Light

Oxygen

Spatial needs

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Abiotic Effects in Ecosystem Development

Abiotic Effects in Ecosystem Development

The Energy of Life

Potential vs. Kinetic Energy

The Energy of Life

Thermodynamics –

The Energy of Life

1st Law of Thermodynamics –

energy can change forms, but is not created or destroyed

2nd Law of Thermodynamics –

“Entropy Rules!”

amount of usable energy decreases as energy changes forms

1st Law deals with quantity of energy,

2nd Law with quality of energy.

The Energy of Life

Photosynthesis

6 CO2 + 12 H2O + radiant energy

C6H12O6 + 6 H2O + 6 O2

The Energy of Life

Cellular Respiration

C6H12O6 + 6 O2 + 6 H2O

6 CO2 + 12 H2O + energy

The Energy of Life

Case-in-Point: Life Without the Sun

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Trophic Categories

AutotrophsProducers – make their own organic food

from inorganic materialsSome bacteria, algae, plants

Heterotrophs Consumers – eat live plants and/or animals

From bacteria to blue whales

Detritus feeders and decomposers – eat dead matter

Ravens and vultures; bacteria, earthworms, some insects

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Trophic Categories and Terminology

Autotrophs Heterotrophs

Producers Consumers Decomposers & Detritus Feeders

Photosynthetic Primary

Chlorophyll Herbivores Fungi, Bacteria, Earthworms

Purple Pigments Secondary Hydrogen Sulfide Carnivores

Omnivores Parasites

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AutotrophsAutotrophs

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Trophic Relationships Among Producers and

Consumers

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Detritus Feeders

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Trophic LevelsTrophic Levels

Third-order Consumer

Secondary Consumer

Primary Consumer

Producer

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Match Organisms With Trophic Level(s)

Trophic Levels

Organisms

Producer Primary Consumer

Secondary Consumer

Third-Order Consumer

Plants X

Rabbits X

Snakes X

Owls X X

Bacteria X X X X04/22/23

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Match Organisms With Trophic Level(s)

Trophic Levels

Organisms

Producer Primary Consumer

Secondary Consumer

Third-Order Consumer

Autotrophs

X

Herbivores

X

Carnivores

X X

Omnivores

X X X

Parasites X X X

04/22/23

The Path of Energy Flow

Food Chains –

The Flow of Energy Through Ecosystems

Producers, Consumers, and Decomposers

Food Webs –

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Marine Food Web

The Path of Energy Flow

Case-in-Point: How Humans Have Affected the Antarctic Food Web

Krill

Baleen whales

Squid Fishes

Toothed whalesSealsPenguins

What would happen if you eliminated krill?

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Where the Biomass Comes From

The Path of Energy Flow

Ecological Pyramids

Pyramid of Numbers Pyramid of Biomass

The Path of Energy Flow

Ecological Pyramids

Pyramid of Energy

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Trophic Level Energy Exchanges

Trophic Level Energy Exchanges

Third-order Consumer

Secondary Consumer

Primary Consumer

Producer10,000 Kcal

- 100x

- 10x

- 10x

100 Kcal

10 Kcal

1Kcal

The Path of Energy Flow

Example: Thermodynamics in Action

Desert: Primary producers = 100 g / m2

Temperate forest: Primary producers = 1,500 g / m2

Food webs very simple, very few tertiary consumers

Food webs very complex, more tertiary consumers, some quaternary.

The Path of Energy Flow

Desert Biomass Pyramid

Primary producers = 100 g / m2

Primary consumers = 10 g / m2

Secondary consumers = 1.0 g / m2

Tertiary consumers = 0.1 g / m2

Tertiary consumers must range over large areas to obtain enough energy to subsist.

such as . . .13.5 kg coyote must range ~12 ha to subsist (30 acres).

The Path of Energy Flow

Temperate Forest Biomass Pyramid

Primary producers = 1,500 g / m2

Primary consumers = 150 g / m2

Secondary consumers = 15 g / m2

Tertiary consumers = 1.5 g / m2

13.5 kg coyote only needs ~1 ha to subsist (2.5 acres).

Also, possibility of quaternary consumers, like bears.

NOTE: just relative examples, not accurate

The Path of Energy Flow

Ecosystem Productivity