Lecture 2 - websites.rcc.eduwebsites.rcc.edu/halama/files/2020/06/Biology-19... · Lecture 2 1. Ecology ... •Biosphere contains all earth’s ecosystems but these systems interact

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© 2015 John Wiley & Sons, Inc. All rights reserved.

Website:

websites.rcc.edu/halama


Lecture 2

Energy and Ecosystems

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Lecture 2

1. Ecology

• The Ecological Hierarchy

2. Energy

• Laws of Thermodynamics

• Photosynthesis and Cellular Respiration

3. Flow of Energy Through Ecosystems

• Producers, Consumers and Decomposers, etc

• Path of Energy Flow: Who Eats Whom


Ecology

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Popular vs. Scientific

Ecology


Ecology

•A branch of the Biological Sciences

• Study of one’s house - “logy” study of, “eco”

house

1. The study of interactions among and between

organisms in their environment, or

2. Study of the structure and function of nature

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Ecology

Biotic - living environment

–Includes all organisms (plants, animals, etc.)


EcologyAbiotic - non living or physical environment

–Includes: sunlight, soil, precipitation, water,

pollutants, etc.

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Ecology

• Organisms interact with

other biotic components,

but also effect many

physical and chemical

processes

• Physical – walking on

soil, digging burrows,

gnawing trees, etc.

• Chemical – CO2, O2,

wastes


Ecology

Ecological Hierarchy

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Ecology Hierarchy


Ecology

•Autecology – study of the organism, physiology, natural history, genetics, etc.

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Ecology Hierarchy

• Species - similar organisms that can freely

interbreed to produce fertile offspring

• Currently – 1.2 million

• Estimates – 8.7 million +

• Maybe more????


Ecology Hierarchy

• Population - A group of organisms of the same

species that live in the same area at the same

time

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Ecology Hierarchy

• Community - All the populations of different

species that live and interact in the same area

at the same time

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Ecology Hierarchy

• Community - All the populations of different

species that live and interact in the same area

at the same time


Ecology Hierarchy

• Ecosystem - A community (biotic) and its

physical (abiotic) environment

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Ecology Hierarchy

• Landscape - Several interacting ecosystems

(ex: bear hunting for salmon in a river, living

in adjacent forest)


Ecology Hierarchy• Biome - an area of the planet that can be classified according to the plants and

animals that live in it.

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Ecology Hierarchy

• Biosphere – all the areas of the earth that

contain living organisms; the global sum of

all ecosystems.


Part of Earth that contains living organisms

Ecology Hierarchy

Community and physical environment

Individuals

Group of same species

All populations of species in an area

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Biodiversity• The variety of life on Earth at all its levels, from genes to

ecosystems, and can encompass the evolutionary, ecological,

and cultural processes that sustain life.


Ecology

• Biosphere contains all earth’s ecosystems but

these systems interact with the three main

abiotic realms:

• Atmosphere- gaseous

envelope surrounding earth

• Hydrosphere- earth’s supply

of water

• Lithosphere- soil and rock of

the earth’s crust

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Ecology

Lithosphere

Hydrosphere

Atmosphere


Energy

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Energy


Energy of Life• The ability or capacity to do work

• Chemical, Thermal (Heat), Mechanical (Motion),

Nuclear, Electrical, and Radiant/Solar (below)

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Energy Basics

• Energy exists as:

–Potential energy

(stored energy)

–Kinetic energy

(energy of motion)

Potential energy is converted to kinetic energy as

arrow is released from bow


Thermodynamics• Study of energy and its transformations

(potential energy to kinetic energy, etc.)

• System- the object being studied

• Closed System- Does not

exchange energy with

surroundings (very rare in

nature)

• Open System- exchanges

energy with surroundings

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Laws of Thermodynamics

• First Law of Thermodynamics

–Energy cannot be created or destroyed; it can

change from one form to another

– a.k.a. Conservation of Energy


Laws of Thermodynamics

• Second Law of Thermodynamics

–When energy is converted form one form to

another, some of it is lost as heat

• E.g. - Engine converts the

chemical energy of gasoline

into mechanical energy

• inefficiently…

mechanical energy + heat

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Energy Basics

• Solar radiation is the primary source of

energy on planet

• Powers ALL life on the planet (99%)

Plants turn solar

radiation into food


All energy on this planet…

Mr. Sun

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Photosynthesis (in Plants)

• A biological process - energy from the sun (radiant energy) is transformed into chemical energy of carbohydrate (sugar) molecules (potential energy)

6 CO2 + 12 H2O + radiant energy

C6H12O6 + 6 H2O + 6 O2

Chlorophyll in plants

Potential Energy



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Cellular Respiration

• The process where the chemical energy captured in

photosynthesis (PE) is released (KE) within cells of

plants and animals

• This energy is then used for biological work

C6H12O6 + 6 O2 + 6 H2O

6 CO2 + 12 H2O + energy (kinetic energy)


Photosynthesis and Cellular

Respiration

Represent an Open System

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Life without Sun

• 1970s – discovered hydrothermal vents in deep

ocean (200oC or 392oF)

• Rich ecosystem supported without light

• Bacteria perform

chemosynthesis

• Similar to

photosynthesis, but

use chemical (H2S)

not sunlight


Energy Flow Through

Ecosystems

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Food Chain• A hierarchical sequence of organisms through

which matter and energy pass as one organism

eats another.


Food Chains

The Path of Energy Flow

• Energy from food passes from one organism to

another based on their Trophic Level

Trophic Level - An organism’s position in a

food chain, which is determined by its feeding

relationships

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Energy Flows Through Ecosystems

• Passage of energy through an ecosystem


Food Chains


• First Trophic Level- Producers (plants)

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Food Chains


• Second Trophic Level- Primary Consumers


Food Chains


• Third Trophic Level- Secondary Consumers

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Food Chains


• Fourth Trophic Level- Tertiary Consumers


Food Chains


• Decomposers are present at all trophic levels

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Food Chains• Autotrophs = Producers (First Trophic Level)

–Auto “self ” and tropho “nourishment”

–Produce own food from inorganic material

–Ex: plants via photosynthesis and hydrothermal vent

bacteria via chemosynthesis


Food Chains

• Heterotrophs = Consumers

–heter “different” and tropho “nourishment”

–Uses bodies of other organisms as food

• Omnivores – eat both plants and animals

• Carnivores – eat other animals

• Herbivores – eat plants

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Food Chains

• Consumers of detritus (detritivores)

–Eat dead material such as leaves, carcasses, feces

–Ex: crabs, worms, millipedes, snails


Food Chains• Decomposers or saprotrophs

– sapro “rotten” and tropho “nourishment”

–Breakdown dead organic material

–Release inorganic molecules (CO2 and nutrients) that

producers can use

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Food Web

• Food Web - feeding

relationships within a

community

–More complex than food

chain

–Still simplified compared

to nature


Ecological Pyramids• Graphically represent the relative energy value

of each trophic level

–Important feature - large amount of energy is lost

as heat between trophic levels

–Only 10% of the energy available to the next level

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Pyramid of Numbers

• Illustrates the number of organisms at each

trophic level

• Fewer organisms occupy

each successive level


Pyramid of Biomass

• Illustrates the total biomass at each successive

trophic level

• Biomass: measure of

the total amount of

living material

• ~90% reduction in

biomass through

trophic levels

• 100 to 10

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Pyramid of Energy

• Illustrates how much energy is present at each trophic

level and how much is transferred to the next level

• Most energy dissipates

between trophic levels

• Lost as heat and energy

to maintain each level

• Explains why there are

so few trophic levels


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Documents

Lecture 2 - websites.rcc.eduwebsites.rcc.edu/halama/files/2020/06/Biology-19... · Lecture 2 1. Ecology ... •Biosphere contains all earth’s ecosystems but these systems interact