esc 301.02 ii ecology b short (1)

7/29/2019 Esc 301.02 II Ecology b Short (1)

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ESC 301

ECOLOGY-Part B

Ferhan een


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A grouping of plants, animals, and microbes

occupying an explicit unit of space and interacting

with each other and their environment.

ECOSYSTEMS


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The Source of High Quality Energy

Energy of sunlights and

warms theplanet

Supportsphotosynthesis

Powers thecycling ofmatter

Drives climateand weatherthat distributeheat and H2O

Solar

radiationEnergy in = Energy out

Reflected byatmosphere (34%)

UV radiation

Absorbed

by ozone

Absorbed

by the earth

Visible

light

Lower Stratosphere

(ozone layer)

Troposphere

Heat

GreenhouseGreenhouse

effecteffect

Radiated by

atmosphereas heat (66%)

Earth

Heat radiatedby the earth


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Energy and Matter Flow in Ecosystems1. Most ecosystems fix less than 1 % of the

sunlight available for photosynthesis.

2. Living organisms can use energy in basically two

forms: radiant or fixed.

3. Radiant energy exists in the form of

electromagnetic energy, such as light.

4. Fixed energy is the potential chemical energy

found in organic substances.


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Energy and Matter Flow in Ecosystems1. Organisms that can take energy from inorganic

sources and fix it into energy rich organic

molecules are called autotrophs.

2. If this energy comes from light then these

organisms are called photosyntheticautotrophs. THE PLANTS

3. Organisms that require fixed energy found inorganic molecules for their survival are called

heterotrophs. THE ANIMALS


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Energy and Matter Flow in Ecosystems1. Heterotrophs who obtain their energy from

living organisms are called consumers.

2. Consumers that consume plants are known as

herbivores.

3. Consumers that consume other animals are

known as carnivores.

4. Decomposers or detritivores are heterotrophs

that obtain their energy either from dead

organisms or their remains.


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Energy and Matter Flow in Ecosystems1. Radiant energy is used by plants in the process

ofphotosynthesis.

2. Fixed energy is used by all organisms in the

process ofrespiration.

3. Once fixed by plants, organic energy can move

within ecosystems.


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ProducersProducers


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Photosynthesis

6 CO2 + 6 H20 C6H12O6 + 6 O2

Respiration

C6H12O6 + 6 O2 6 CO2 + 6 H20


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Energy and Matter Flow in Ecosystems1. Organisms can be eitherproducers or

consumers in terms of energy flow through an

ecosystem.

2. Producers (Plants, autotrophs) take energy

from sunlight and use it to convert carbondioxide into glucose (or other sugars).

3. Consumers (Animals, heterotrophs) get theirenergy from the organic compounds (carbon

bonds) made by the producers.


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Consumers

Primary consumers = herbivores = rabbits: eat

plant material Secondary consumers = carnivores =

predators = coyotes: prey are herbivores and

other animals Parasites = predator = either plant or animal:

prey are plants or animals

Detritus feeders and decomposers = bacteriaand fungi: prey are plants or animals


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Trophic Relationships

Food chains: feeding pathways

Food chains are a description of who eats whom.

Predator-prey and host-parasite describe specific feeding relationships.

Food webs: complex feeding relationships.

Trophic Levels or Feeding Levels

All producers belong to the first trophic level.

All herbivores (primary consumers) are on the second trophic level.

All primary carnivores (secondary consumers) are on the third trophic level.


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Trophic Categories


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Ecosystem function

Energy flows through ecosystems

Chemical matter cycles within and/or

between ecosystems


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Matter and Energy Energy: anything that has the ability to move matter; has no mass

and does not occupy space

Cannot be created or destroyed Can be changed from one form to another

Cannot be recycled

Can be measured

Matter: anything that occupies space and has mass

Cannot be created or destroyed

Can be changed from one form into another

Can be recycled

Can be measured where gravity is present


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Laws of Thermodynamics

First Law: Energy is neither creatednor destroyed but may be converted from one

form to another.

Second Law: In any energy conversion,

you will end up with less usable energy thanyou started with.


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Energy and Matter Flow in Ecosystems

Most of the most importantrelationships between living organisms

and the environment are controlled

directly or indirectly by the amount of

available incoming energy received at

the Earth's surface from the sun.


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Energy Flow through Trophic Levels


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The Law of 10 %

On the average about 10 % of

the energy entering a feedinglevel (trophic level) is transferred

to the next one.


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Biomass and Biomass Pyramida. All organic matter can be defined as biomass.

b. All biomass can be arranged into a feedingrelationship with the producers on the firsttrophic level.

c. On average, 10% of the energy from one trophic

level moves to the next trophic level. (This isdue partly to the First and Second Laws ofthermodynamics.) At each trophic level most ofthe organisms are not consumed, portions of

organisms consumed pass through theconsumer undigested, and energy is released tothe environment as high potential energy isconverted to low potential energy.


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d. Because so little energy can be transferredbetween trophic levels, it is necessary that the firsttrophic level contains the greatest number oforganisms, and the subsequent trophic levelscontain fewer and fewer organisms. Limitations on

the transfer of energy between trophic levelscreates the biomass pyramid.

e. If organisms (humans) eat high on the biomasspyramid (trophic levels 3, 4, 5, etc.), then fewer

organisms can be supported than if organisms eatlower on the biomass pyramid.

Biomass and Biomass Pyramid


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Ecological Pyramids of Biomass


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Ecological Pyramids of Energy


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The conversion of light energy to chemical

energy is called gross primaryproduction.

Plants use the energy captured inphotosynthesis for maintenance and

growth.

The energy that is accumulated in plantbiomass is called net primary production.

PRIMARY PRODUCTIVITY


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Primary Productivity NPP=GPP-respiration rate

GPP= RATE at which producers convert solarenergy into chemical energy as biomass Rate at which producers use photosynthesis to fix

inorganic carbon into the organic carbon of theirtissues

These producers must use some of the totalbiomass they produce for their own respiration

NPP= Rate at which energy for use byconsumers is stored in new biomass

(available to consumers) Units Kcal/m2/yr or g/m2/yr

Most productive vs. least productive


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What are the most productive

Ecosystems?EstuariesEstuaries

Sw amps and marshesSw amps and marshes

Tropical rain forestTropical rain forest

Temperate forestTemperate forest

Northern coniferous forest (taiga)Northern coniferous forest (taiga)

SavannaSavanna

Agricultural landAgricultural land

Woodland andWoodland and shrublandshrubland

Temperate grasslandTemperate grassland

Lakes and streamsLakes and streams

Continental shelfContinental shelf

Open oceanOpen ocean

Tundra (arctic and alpine)Tundra (arctic and alpine)

Desert scrubDesert scrub

Extreme desertExtreme desert

800800 1,6001,600 2,4002,400 3,2003,200 4,0004,000 4,8004,800 5,6005,600 6,4006,400 7,2007,200 8,0008,000 8,8008,800 9,6009,600

Average net primary productivity (kcal/mAverage net primary productivity (kcal/m 22/yr)/yr)


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Biodiversity Variety of living things,

number of kinds

Ecological diversity different habitats, niches,

species interactions

Species diversity different kinds oforganisms, relationshipsamong species

Genetic diversity different genes &combinations of genes


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Benefits of Biodiversity New food sources

Grains, fruits, vegetables, meat, fish


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Benefits of Biodiversity Medicines

Plants

Jellyfish & seaanemones

Nudibranchs


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Threats to Biodiversity Extinction and

population reductions Hunting and

overharvesting

Tiger

Dodo

Whales

Sharks

Habitat loss Pollution

Climate change

Invasive species


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Protecting Biodiversity How can we protect

biodiversity Stop overharvesting

Sustainable yield

Hunting & fishing laws

(every state ?)

in developing nations ?

Refuges, parks,

preserves

Endangered Species Act

esc 301.02 ii ecology b short (1)

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