Energy Transfer & Nutrient Cycling. How is energy transferred in an ecosystem? Organisms in a community survive by either producing or consuming food

Energy Transfer & Nutrient Cycling

How is energy transferred in an ecosystem?

Organisms in a community survive by either producing or consuming food


Trophic levels - levels of feeding in a community


Producers - produce food for themselves (ex. plants),

Other organisms may eat producers.


Consumers - must take in food (ex. fungi)

Primary Consumers - also called herbivores (ex. cow)

Energy Flow Consumers- organism that relies on other

organisms for its energy and food supply (Heterotrophs)– Herbivores- eat only plants– Carnivores- eat animals– Omnivores- eat both plants and animals– Detritivores- feed on plant and animal remains

and other dead matter (mites, earthworms)– Decomposers- breaks down organic matter

(bacteria and fungi)

What is it?

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http://en.wikipedia.org/wiki/File:Porcellio_scaber_-_male_front_2_(aka).jpg


Secondary and Tertiary Consumers - may be carnivores (ex. lion) or omnivores (ex. bear)


Decomposers - as they consume, they break down wastes and dead organisms and return nutrients to the soil.

Food Webs

Made up of overlapping food chains.

Food Webs

Shows feeding connections; arrows illustrate energy transfer

Ex:

Food Web A network of

complex interactions that links all the food chains in an ecosystem together

Fill It In …

Answer using the food web:

1. Organisms that eat grass.

2. Food sources for the fox.

3. An “omnivore”.4. An “herbivore”.5. A “carnivore”.

Ecological Efficiency

Producers have the most available energy (sun).

Energy is lost as it moves up through the food web; 10% rule - only 10% of the available energy is passed to the next trophic level.

Biomass Pyramid Biomass- the total

amount of living tissue within a given trophic level

Pyramid represents the amount of potential food available at each trophic level

Pyramid of Numbers B. Energy is lost from

level to level as: 1. Heat (due to

cellular respiration conversions)

2. Unused material

3. Waste Based on the number of

organisms at each level

Could this pyramid look any differently?

Ecological Efficiency

The “lost” energy is used to catch, eat, and digest food

Fill It In …

10% Rule:Carnivores (_____ cal)

Herbivores (_____ cal)

Plants (1000 cal)

Bioaccumulation in NC

1. Bioaccumulation: the build up in higher trophic levels of certain chemicals like mercury and pesticides.

2. Almost all samples of fish taken from NC rivers contain some level of mercury.

3. Large mouth bass has been placed on a consumption advisory.

Check Yourself!1. What is a trophic level?

2. What is the difference between an omnivore and a carnivore?

3. From the food web above, write out a food chain that includes the rat.

4. Which level in a food web has the most energy?

Check Yourself!1. What is a trophic level? LEVELS OF

FEEDING IN A COMMUNITY2. What is the difference between an omnivore

and a carnivore?





and a carnivore? OMNIVORE EATS PLANTS AND MEAT, CARNIVORE EATS ONLY MEAT






3. From the food web above, write out a food chain that includes the rat. (ANSWERS WILL VARY)





3. From the food web above, write out a food chain that includes the rat. (ANSWERS WILL VARY)

4. Which level in a food web has the most energy? PRODUCER

How is matter reused in an ecosystem?

Role of decomposers Decomposers break

down wastes and dead organisms

Decomposition allows nutrients to be returned to the soil and atmosphere; this allows nutrients to be reused.

Decomposers include fungi, bacteria, and invertebrates


Biogeochemical Cycles - the pathway through which a substance is recycled

Water cycle– Enters ecosystem by

precipitation; may infiltrate the soil (be absorbed) or run-off into surface water


Water cycle– Returned to atmosphere

by evaporation or transpiration (the loss of water by plants)

Fill It In … Diagram of water cycle:


Carbon cycle– Powered by two

main processes– Photosynthesis -

plants and algae capture CO2 from the air and change it into sugar (which have carbon)


Carbon cycle– Respiration - all

living things break down sugars for energy, which returns CO2 to the atmosphere


Carbon cycle– Other factors in the

carbon cycle:– Decomposition

returns carbon to the soil and atmosphere


Carbon cycle– Humans burn fossil

fuels which adds CO2 to the atmosphere

– Deforestation removes tress which normally photosynthesis and remove CO2 from the atmosphere


CARBON

CYCLE

Fill It In …

Factors that ADD carbon to atmosphere:

Factors that REMOVE carbon from atmosphere:

Using the Carbon Cycle diagram on page 77 of textbook:

1. What are the 4 sources/processes that ADD carbon to the atmosphere?

2. What are the 2 sources/processes that REMOVE carbon from the atmosphere?

3. What process do animals carry out that adds CO2 to the atmosphere?

4. What process do plants carry out that removes CO2 from the atmosphere?

5. The combustion of _______ by humans can add CO2 to the atmosphere.

6. ______ of dead organisms may return carbon to the soil.

7. How is carbon stored in plants transferred to animals?


Nitrogen Cycle– Nitrogen is essential

for living organisms so that they can build proteins; nitrogen is plentiful in the atmosphere, but is not usable in this form.


Nitrogen Cycle– Nitrogen fixation -

bacteria living in the root nodules of bean plants (legumes) convert nitrogen from the air into a more usable form.


Nitrogen Cycle– Nitrogen fixation is

the first of many steps that involves bacteria and changing the form of nitrogen.

Nitrogen Cycle Questions What are the main nitrogen containing nutrients in

the biosphere?– ammonia, nitrate, nitrite

What controls the primary productivity of an ecosystem?– the amount of available nutrients

What is a limiting nutrient?– a single nutrient that is scarce or cycles very slowly

Why do algal blooms occur?– when more nutrients are available and producers

can produce more than consumers can eat What does “equilibrium” of an ecosystem mean?

– equilibrium = balance

Check Yourself!1. How do decomposers help with the recycling of

nutrients?

2. How do plants return water to the atmosphere?

3. What two processes drive the carbon cycle?

4. What organisms are essential for the conversion of nitrogen?


nutrients? BREAK DOWN WASTES & DEAD ORGANISMS TO ALLOW NUTRIENTS TO BE RETURNED TO THE SOIL OR ATMOSPHERE

2. How do plants return water to the atmosphere?





2. How do plants return water to the atmosphere? TRANSPIRATION






3. What two processes drive the carbon cycle? PHOTOSYNTHESIS & RESPIRATION





3. What two processes drive the carbon cycle? PHOTOSYNTHESIS & RESPIRATION

4. What organisms are essential for the conversion of nitrogen? BACTERIA

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Energy Transfer & Nutrient Cycling. How is energy transferred in an ecosystem? Organisms in a community survive by either producing or consuming food