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KEY CONCEPT Life in an ecosystem requires a source of energy. PowerPoint PPT Presentation


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KEY CONCEPT Life in an ecosystem requires a source of energy. What have we learned about the relationship between predators and prey?. A dvantages : provides food for predators

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KEY CONCEPT Life in an ecosystem requires a source of energy.

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Key concept life in an ecosystem requires a source of energy

KEY CONCEPT Life in an ecosystem requires a source of energy.


What have we learned about the relationship between predators and prey

What have we learned about the relationship between predators and prey?

Advantages:

  • provides food for predators

  • predators keep prey populations at just the right number so prey doesn't overcrowd and area and throw the ecosystem off

  • the constant need for evolution to better the chances of prey living and to better the chances of predators catching prey

    Disadvantages:

  • non native introduction of predators or the introduction of more can wipe out prey species


Prefixes a brief detour

Prefixes: A brief detour

  • Auto- ?

  • Hetero- ?

  • Homo- ?

  • Photo- ?

  • Chemo- ?

  • Herbi- ?

  • Carni- ?

  • Omni- ?

  • Hydro- ?


Prefixes

Prefixes

  • Auto- Self

  • Hetero- Different

  • Homo- Same

  • Photo- Light

  • Chemo- Chemical

  • Herbi- Plants

  • Carni- Meat

  • Omni- All

  • Hydro- Water


Key concept life in an ecosystem requires a source of energy

An “Ecological System?”

In the discipline of ecology, the word

Ecosystem is an abbreviation of the term,ecologicalsystem – the basic unit in ecology.

.

SirArthur Tansley(1871-1955)


Key concept life in an ecosystem requires a source of energy

An “Ecological

System?”

Components of an Ecosystem:

Biotic Components and Abiotic (non-living)

Sir Arthur Tansley (1871-1955)

Physical Components

Water

Nutrients

Topography

Weather

Disturbances

Species

Populations

Communities

Competition and Predation


What keeps us and other organisms alive

What Keeps Us and Other Organisms Alive?

  • One-way flow of high-quality energy from the sun (returned as low quality heat)

  • Cycling of matter or nutrients through parts of the biosphere (closed system applies; law of conservation of matter; time frame of seconds to centuries)

  • Gravity (maintains atmosphere, enables movement & cycling of air, water, nutrients)


Key concept life in an ecosystem requires a source of energy

Energy and the Laws of

Thermodynamics

20.1 – The Laws of Thermodynamics Govern Energy Flow.

Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy.

Kinetic

energy

Entropy

Entropy

Potential

energy


Key concept life in an ecosystem requires a source of energy

Energy and the Laws of

Thermodynamics

The 1st Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed.

The total amount of energy and matter in the Universe remains constant, merely changing from one form to another.

Isaac Newton (1643-1727)


Key concept life in an ecosystem requires a source of energy

Energy and the Laws of

Thermodynamics

The 2nd Law of Thermodynamics: "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state." In energy transfer, some energy will dissipate as heat. The flow of energy maintains order of life.

Isaac Newton (1643-1727)


Key concept life in an ecosystem requires a source of energy

  • - Scientists have studied many ecosystems and have concluded that this energy loss is a constant pattern. In fact, scientists have calculated that the percentage (%) of usable energy transferred from one organism to another is 10%.

  • !! – That means that 90% of energy is lost as heat!!!

  • So…. if producers captured 10,000 calories from the sun, then only bout 1,000 calories will be available to support primary consumers (herbivores), and only about 100 calories to support secondary consumers (carnivores or omnivores).


10 law

10% LAW.. !!

  • In the Arctic, Eskimos hunt whales for food. Whales eat tons and tons of microscopic plankton. This plankton in turn eats microscopic algae.

  • It requires 1,000 units of energy (calories) of algae to produce 100 calories of plankton which is what a whale uses to produce 10 calories of blubber (fat) to its body.

  • Finally these 10 calories of whale blubber contains enough energy to give the Eskimo one calorie of energy.


Producers provide energy for other organisms in an ecosystem name three producers

Producers provide energy for other organisms in an ecosystem. Name three producers.

  • Producers get their energy from non-living resources.

  • Producers are also called autotrophs because they make their own food.


Producers provide energy for other organisms in an ecosystem

Producers provide energy for other organisms in an ecosystem.

  • Consumers are organisms that get their energy by eating other living or once-living resources. Name 3 consumers.

  • Consumers are also called heterotrophs because they feed off of different things.


Key concept life in an ecosystem requires a source of energy

carbon dioxide + water +

hydrogen sulfide + oxygen

sugar + sulfuric acid

Almost all producers obtain energy from sunlight. If the producer doesn’t use sunlight, what might they use?

  • Photosynthesis in most producers uses sunlight as an energy source.

  • Chemosynthesis in prokaryote producers uses chemicals as an energy source.


Key concept life in an ecosystem requires a source of energy

KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.


A food chain is a model that shows a sequence of feeding relationships why does chain fit this idea

GRAMA GRASS

DESERT COTTONTAIL

HARRIS’S HAWK

A food chain is a model that shows a sequence of feeding relationships. Why does “chain” fit this idea?

  • A food chain links species by their feeding relationships.

  • A food chain follows the connection between one producer and a single chain of consumers within an ecosystem.


Create your own food chain

Create your own food chain

  • Beginning with a producer and including at least three organisms, give an example of a food chain.


Key concept life in an ecosystem requires a source of energy

carnivore

decomposer

  • Herbivores eat only plants.

  • Carnivores eat only animals.

  • Omnivores eat both plants and animals.

  • Detritivores eat dead organic matter.

  • Decomposers are detritivores that break down organic matter into simpler compounds.

  • Consumers are not all alike.


Key concept life in an ecosystem requires a source of energy

  • Specialists are consumers that primarily eat one specific organism or a very small number of organisms. What other kinds of “specialists” do you know?

  • Generalists are consumers that have a varying diet.


Key concept life in an ecosystem requires a source of energy

  • Primary consumers are herbivores that eat producers.

  • Secondary consumers are carnivores that eat herbivores. Name one example.

  • Tertiary consumers are carnivores that eat secondary consumers. Name one example.

  • Omnivores, such as humans that eat both plants and animals, may be listed at different trophic levels in different food chains.

  • Trophic levels are the nourishment levels in a food chain.


A food web shows a complex network of feeding relationships

A food web shows a complex network of feeding relationships.

  • An organism may have multiple feeding relationships in an ecosystem. Give an example.

  • A food web emphasizes complicated feeding relationships and energy flow in an ecosystem.


A food web shows a complex network of feeding relationships1

A food web shows a complex network of feeding relationships.


Trophic levels

Trophic Levels

  • Producers – autotrophs

    -Photosynthesis

  • Consumers – heterotrophs

    -Primary

    -Secondary

    -Third-level

  • Omnivores

  • Detritus feeders / Decomposers


Trophic levels1

20 energy

10 consumer energy

Producers energy

Trophic Level = Feeding Level

Trophic Levels

- Just like a skyscraper has floors, or levels, an energy Pyramid has distinct levels, called TROPHIC LEVELS.


Key concept life in an ecosystem requires a source of energy

4th Tr. Level

3rd Trophic Level

2nd Trophic Level

1st Trophic Level

1 calorie

eskimos

10 calories

whales

100 calories

plankton

1000 calories

algae

A healthy ecosystem will always have the most energy available in the first trophic level.


Key concept life in an ecosystem requires a source of energy

Ecosystem Energetics

- Energy Decreases in Each Successive Trophic Level.


Ecological pyramids

carnivores

herbivores

producers

Ecological pyramids

  • The standing crop, productivity, number of organisms, etc. of an ecosystem can be conveniently depicted using “pyramids”, where the size of each compartment represents the amount of the item in each trophic level of a food chain.

Note that the complexities of the interactions in a food web are not shown in a pyramid; but, pyramids are often useful conceptual devices--they give one a sense of the overall form of the trophic structure of an ecosystem.


Pyramid of energy

carnivores

herbivores

producers

Pyramid of energy

  • A pyramid of energy depicts the energy flow, or productivity, of each trophic level.

  • Due to the Laws of Thermodynamics, each higher level must be smaller than lower levels, due to loss of some energy as heat (via respiration) within each level.


Pyramids of energy suggests

Pyramids of Energy Suggests:

  • The number of trophic levels are limited. At each trophic level, there is a dramatic reduction in energy.

  • Eating at lower trophic levels means more resources available.

  • Movement up the pyramid explains the problems of Biological Magnification (DDT, PCBs, etc.)


Review what are food chains and food webs

REVIEW: What are Food Chains and Food Webs

How energy moves in an ecosystem

OR

who eats who!? ;)


Key concept life in an ecosystem requires a source of energy

What is a Food Chain?

  • Food Chain: A food chain shows one path of how energy moves through an ecosystem

    What is a Food Web?

  • Food Web: A food web shows many paths of how energy moves through an ecosystem. A food web is made up of many different food chains.


Key concept life in an ecosystem requires a source of energy

FOOD CHAIN


Key concept life in an ecosystem requires a source of energy

F

O

O

D

W

E

B


Primary productivity

Primary productivity

  • Primary productivity is the rate of energy capture by producers.= the amount of new biomass of producers, per unit time and space


Key concept life in an ecosystem requires a source of energy

  • Gross primary production (GPP)

    = total amount of energy captured

  • Net primary production (NPP)

    = GPP - respiration

  • Net primary production is thus the amount of energy stored by the producers and potentially available to consumers and decomposers.


Key concept life in an ecosystem requires a source of energy

  • Secondary productivity is the rate of production of new biomass by consumers, i.e., the rate at which consumers convert organic material into new biomass of consumers.


Conclusion

CONCLUSION

  • Energy flow follows the second law of thermodynamics

  • Biomass decreases with increasing trophic level

  • Ecological efficiency – typically 10%

    Food Web Activity


Key concept life in an ecosystem requires a source of energy

KEY CONCEPT Matter cycles in and out of an ecosystem.


Water cycles through the environment explain how

precipitation

condensation

transpiration

evaporation

surface

runoff

lake

water storage

in ocean

groundwater

seepage

Water cycles through the environment. Explain how.

  • The hydrologic, or water, cycle is the circular pathway of water on Earth.

  • Organisms all have bodies made mostly of water.


Elements essential for life also cycle through ecosystems name one

Elements essential for life also cycle through ecosystems. Name one.

  • A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem.


Key concept life in an ecosystem requires a source of energy

carbon

dioxide

in air

respiration

combustion

photosynthesis

respiration

photosynthesis

decomposition

of organisms

carbon dioxide

dissolved in water

fossil fuels

  • The carbon cycle moves carbon from the atmosphere, through the food web, and returns to the atmosphere.

  • Carbon is emitted by the burning of fossil fuels.

  • Some carbon is stored for long periods of time in areas called carbon sinks.

  • Carbon is the building block of life. Why do we call it that?


Key concept life in an ecosystem requires a source of energy

oxygen

photosynthesis

respiration

carbon

dioxide

  • Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients.


Key concept life in an ecosystem requires a source of energy

rain

geologic uplifting

weathering of

phosphate from rocks

runoff

plants

animals

phosphate

in soil

phosphate in solution

leaching

sedimentation

forms new rocks

decomposers

  • Phosphate is released by the weathering of rocks.

  • Phosphorus moves through the food web and returns to the soil duringdecomposition.

  • The phosphorus cycle takes place at and below ground level.

  • Phosphorus leaches into groundwater from the soil and is locked in sediments.

  • Both mining and agriculture add phosphorus into the environment.


Key concept life in an ecosystem requires a source of energy

nitrogen in

atmosphere

animals

plant

nitrates

nitrogen-fixing

bacteria in roots

decomposers

nitrifying

bacteria

ammonification

nitrites

nitrogen-fixing

bacteria in soil

ammonium

nitrifying

bacteria

denitrifying

bacteria

  • Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation.

  • Some nitrogen-fixing bacteria live innodules on theroots of plants;others livefreely inthe soil.

  • The nitrogen cycle mostly takes place underground.


Key concept life in an ecosystem requires a source of energy

nitrogen in

atmosphere

animals

plant

nitrates

nitrogen-fixing

bacteria in roots

decomposers

nitrifying

bacteria

ammonification

nitrites

nitrogen-fixing

bacteria in soil

ammonium

nitrifying

bacteria

denitrifying

bacteria

  • Nitrogen moves through the foodweb and returnsto the soil duringdecomposition.


Key concept life in an ecosystem requires a source of energy

How do the activities of a keystone species affect the biodiversity of an ecosystem?

  • A. They increase biodiversity.

  • B. They decrease biodiversity.

  • C. They have no effect on biodiversity.

  • D. Biodiversity remains the same but the species change.


Key concept life in an ecosystem requires a source of energy

How do the activities of a keystone species affect the biodiversity of an ecosystem?

  • A. They increase biodiversity.

  • B. They decrease biodiversity.

  • C. They have no effect on biodiversity.

  • D. Biodiversity remains the same but the species change.

  • Correct Answer = A

    Which is a characteristic of an ecosystem in approximate equilibrium?

  • A. The kinds of organisms do not change.

  • B. Biotic factors do not change.

  • C.Abiotic factors do not change.

  • D. The total number of organisms do not change.


Key concept life in an ecosystem requires a source of energy

How do the activities of a keystone species affect the biodiversity of an ecosystem?

  • A. They increase biodiversity.

  • B. They decrease biodiversity.

  • C. They have no effect on biodiversity.

  • D. Biodiversity remains the same but the species change.

  • Correct Answer = A

    Which is a characteristic of an ecosystem in approximate equilibrium?

  • A. The kinds of organisms do not change.

  • B. Biotic factors do not change.

  • C.Abiotic factors do not change.

  • D. The total number of organisms do not change.

  • Correct Answer = D


Review

Review

  • Producers are organisms that can make their own energy from abiotic sources

  • Consumers are organisms that must consume other organisms for energy.

  • A food chain links organisms by their feeding relationships connecting a producer to a single line of consumers.

  • A food web shows complicated feeding relationships

  • Water, nitrogen, oxygen, phosphorous, and carbon all cycle through ecosystems.


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