Ecosystems

and Energy

Chapter 4

What is Ecology?

Ecology –

- eco - house; logi - study of

- study of the interactions among organisms and between

organisms (biotic) and their abiotic environment.

What is Ecology

Biotic - living part of the environment

Abiotic - nonliving or physical part of the environment

environment

bioticabioticECOLOGY

What is Ecology?

Levels of Biological

Organization

• Ecology focuses on levels

above the organismal level.

What is Ecology?

Population - same species living

at the same place at the same

time

Species - group of similar organisms whose members freely

interbreed with one a another in the wild to produce fertile

offspring

What is Ecology?

Community - Populations of different species living

together in the same place at the same time.

What is Ecology?

Ecosystem - community AND the physical

environment; includes all the interactions among

organisms and with their abiotic environment

CO2

What is Ecology?

Landscape –

region that includes

several ecosystems

What is Ecology?

Biosphere

the whole earth

interaction of land, water, and atmosphere

contains all living things

Atmosphere

gaseous envelope surrounding Earth

Hydrosphere

Earth’s supply of water

Lithosphere

soil and rock of Earth’s crust

Energy

• The ability to do work.

• Measured in kJ or kcal.

• Energy exists in many forms.

The Energy of Life

Potential vs. Kinetic Energy

PE = stored energy KE = energy of motion

Can change from one form to another

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 –

amount of usable energy decreases as energy changes forms

“Entropy Rules!”

1st Law deals with quantity of energy,

2nd Law with quality of energy.

What do you think?

Quick Write

Use the following scientific terms to describe the

processes of photosynthesis and respiration:

Carbon dioxide

Oxygen

Water

Autotrophs

Heterotrophs

Solar energy

ATP

What is photosynthesis?

Photosynthesis, chemical equation

6 CO2 + 6 H2O + radiant energy

C6H12O6 + 6 O2

What is photosynthesis?

photo = light

synthesis = to put together

Purpose of Photosynthesis

Photosynthesis- turns energy into sugars

Energy Sugars

Photosynthesis

Process of Photosynthesis CO2 enters and O2 exits through stomata

stomata - small openings on the underside of leaves.

Process of

Photosynthesis

Water enters through

roots

Process of Photosynthesis

Light is captured by chlorophyll found in chloroplasts.

chlorophyll - light capturing pigment in chloroplast

Absorbs red and blue light from the sun.

Reflects green light.

Process of Photosynthesis

Process of Photosynthesis

Chloroplast

Organelle that contains chlorophyll.

Site of photosynthesis.

Cellular Respiration

Cellular Respiration:

C6H12O6 + 6 O2

6 CO2 + 6 H2O + energy (ATP)

Photosynthesis vs. Respiration

Photosynthesis- turns energy into sugars

Respiration- turns sugars into energy

Energy Sugars

Photosynthesis

Respiration

What do you think?

Why is it important for scientists to understand how

much photosynthesis is occurring in an ecosystem?

The Path of Energy Flow

Three options for energy use:

Growth, maintenance, reproduction energy is “lost” as

heat through respiration

Storage = biomass available for others to consume

Photosynthesis & Respiration

Gross Primary Productivity (GPP)

total amount of energy captured during photosynthesis

respiration uses some of that energy for life processes

Photosynthesis & Respiration

Net Primary

Productivity (NPP)

amount of energy

remaining in plant

tissues after respiration

only NPP is available to

consumers, and only

some of it is actually

used

Primary Productivity

Ecosystem Productivity

Net Primary

Productivity

Gross Primary

Productivity

Plant cellular

respiration=

Highly Productive Ecosystems

The Path of Energy Flow

Ecosystem Productivity

The Flow of Energy through

Ecosystems

1) Energy enters ecosystem as radiant energy.

2) Some of radiant energy is captured during photosynthesis.

3) Energy is stored in chemical bonds of glucose (chemical energy).

4) Animals get energy by consuming plants and their stored chemical energy.

5) ALL organisms respire to release energy from glucose.

6) Released energy becomes available to do work.

7) Energy escapes from organism as heat = unusable energy.

8) Heat energy radiates into space.

The Flow of Energy Through

Ecosystems

Producers, Consumers, and Decomposers

The Flow of Energy Through

Ecosystems

• Producers• a.k.a. - autotrophs

• Photosynthetic organisms

• Consumers• a.k.a. - heterotrophs

• Organisms who consume producers

• Decomposers• a.k.a. - saprotrophs

• Heterotrophs that break down dead organic material to get energy.

• Releases simple inorganic molecules that can be reused.

The Flow of Energy

through Ecosystems Types of Consumers:• Primary consumer (1o)

• eats producers• Herbivores = plant eaters

• Secondary consumer (2o) • eats 1os• Carnivores = meat eaters• Omnivores = plant and meat eaters

• Tertiary consumers (3o) • eats 2o

• Carnivores or omnivores

• Detritivores• Consume detritus - organic matter that includes carcasses, leaf litter, & feces.

• Helps break down waste products

The Path of Energy Flow

Food Chains – energy from food passes from 1 organism

to the next in a sequence

Trophic Level - each link in the food chain

Food Webs –

interconnected food

chains

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?

The Path of Energy Flow

Ecological Pyramids

Pyramid of Numbers Pyramid of Biomass

The Path of Energy Flow

Ecological Pyramids

Pyramid of Energy

The Path of Energy Flow

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.

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