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Energy Transfer through Food Webs Objective: Understand how energy is transferred through a food chain or web Be able to use a dichotomous key Be able.

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Presentation on theme: "Energy Transfer through Food Webs Objective: Understand how energy is transferred through a food chain or web Be able to use a dichotomous key Be able."— Presentation transcript:

1 Energy Transfer through Food Webs Objective: Understand how energy is transferred through a food chain or web Be able to use a dichotomous key Be able to construct the food web of barn owl Be able to estimate the producer biomass needed to support a barn owl for one year

2 Owl Pellet Safety Wearing gloves Washing hands after use Allergic to pet: contains hair of the prey Pellets: heat sterilized

3 Terminologies Species → Population → Community Autotrophs/ producers Consumers Primary- herbivores Secondary-carnivores Tertiary)-omnivores Detrivores / decomposers : recycles nutrients

4 Background Food chain: Energy moves through a community as organisms feed on one another. Simplified, linear representation of energy flow

5 Food web: complex and realistic shows all possible flow path

6 First Law of Thermodynamics: Conservation of energy Quantity and quality of energy transferred efficiency heat Second Law of Thermodynamics: Entropy: degree of disorder within a system

7 Energy Flow

8 Trophic Structure Pyramid of Number Pyramid of Biomass Pyramid of Energy Example: Eagle/ Top Predato r (0.1 Calories ) Chinook Salmon/ Tertiary consumer (1 Calories) School of minnows/ Secondary consumer (10 Calories) Zooplankton/ Primary Consumers (100 Calories) Phytoplankton/Producers (1000 Calories)

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10 Trophic Level: position in the feeding hierarchy Pyramid of Biomass Pyramid of Energy

11 Constructing a food web and pyramid of biomass for Barn Owl (Tyto alba) Top predator Nocturnal Hunt at night Have an excellent vision Acute sense of hearing Feathery depressions around eyes Swallow whole prey Digest only fleshy parts Indigestible portions of prey : PELLETS or CASTING

12 Needs 6-12 hours to form casting Casting become a home and source of food for a variety of insects Prey:10-15 per night Herbivores: Rodentia eg: mice, voles, rats, pocket gophers. Carnivores: Insectivora eg: moles, shrews Life expectancy: 7-8 years Cosmopolitan Species

13 Procedure Dissect an owl casting Identify the animal remains contained within the casting using a DICHOTOMOUS KEY INSECTIVORA :No Gap(Diastema) between incisors and cheek teeth Zygomatic Arch RODENTIA: Gap (Diastema) between incisors and cheek teeth Infraorbital Canal

14 Hypothesis H 1 :the number of producers that it takes to support a barn owl with a diet consisting Rodent is higher than a diet consisting of Insectivores H 0 :the number of producers that it takes to support a barn owl with a diet consisting Rodent is NOT higher than a diet consisting of Insectivores Homework : Page 41 through 43 Page 44 (Education Majors Only)


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