8.2-Energy-Flow-Through-Ecosystems-AP-Biology.pptx

Energy-Flow-Through-Ecosystems

1. Starter The image below depicts a mother graylag goose retrieving an egg. If an egg rolls from the nest she will reach toward the egg and perform a “chin-tuck” movement to roll the egg back. Experiments have shown that if anything is placed near the nest that looks like an egg (i.e., golf ball) the mother will still go through each step over and over to retrieve the “egg.” What is this type of behavior known as? Is this behavior innate or learned? What served as the sign stimulus for this behavior? Energy Flow Through Ecosystems L/O: To describe the strategies organisms use to acquire and use energy.

2. Ecosystems and Energy Ecosystem : the sum of all the organisms living in a given area and the abiotic factors they interact with Biotic factors : living, or once living, components of an environment Abiotic factors: nonliving (physical and chemical properties of the environment) L/O: To describe the strategies organisms use to acquire and use energy.

3. Ecosystems and Energy Think, pair, share: what are the first two laws of thermodynamics? 1st law : energy can neither be created nor destroyed, only transferred Law of conservation of mass: chemical elements are continually recycled in the environment 2nd law : exchanges of energy increase the entropy of the universe L/O: To describe the strategies organisms use to acquire and use energy.

4. Ecosystems and Energy A net gain in energy results in energy storage or growth of an organism A net loss of energy results in loss of mass and eventual death of an organism L/O: To describe the strategies organisms use to acquire and use energy.

5. Metabolic Rate Metabolic rate : the total amount of energy an animal uses in a unit of time Can be measured in calories, heat loss, or by the amount of oxygen consumed (or CO 2 produced) Oxygen is used in cellular respiration and CO 2 is produced as a by-product An animal’s metabolic rate is related to its body mass Smaller organisms = higher metabolic rate Larger organisms = lower metabolic rate Why might this be?

6. Ecosystems and Energy Organisms use different strategies to regulate body temperature Endotherms : use thermal energy from metabolism to maintain body temperatures Ectotherms : use external sources (ie sun/shade or other organisms) to regulate their body temperature L/O: To describe the strategies organisms use to acquire and use energy.

7. Trophic Levels Species can be grouped into trophic levels based upon their main source of nutrition and energy

8. Trophic Levels Unlike mass, energy CANNOT be recycled The sun constantly supplies energy to ecosystems

9. Trophic Levels Primary producers (autotrophs) use light energy to synthesize organic compounds Plants, algae, photosynthetic plankton Some organisms are chemosynthetic (vs photosynthetic) meaning they produce food using the energy created by chemical reactions i.e. some bacteria and archaea organisms

10. Trophic Levels Heterotrophs rely on autotrophs because they cannot make their own food Primary consumers : herbivores Secondary consumers : carnivores that eat herbivores Tertiary consumers : carnivores that eat other carnivores Decomposers : get energy from detritus (nonliving organic material; leaves, wood, dead organisms) Include fungi and many prokaryotes Important for recycling chemical elements

11. Trophic Structure The trophic structures of a community are determined by the feeding relationships between organisms Food chain : the transfer of food energy up the trophic levels Food webs : linked food chains Notice the arrows show the transfer of energy (i.e. the fish is energy for the bird) L/O: To describe the strategies organisms use to acquire and use energy.

12. Trophic Levels Any changes to the availability of energy can disrupt ecosystems For example: If energy resources change, so can the number and size of trophic levels (Increase energy, increase trophic levels/size; decrease energy, decrease trophic levels/size) A change at the producer level can affect the number and size of the remaining trophic levels L/O: To describe the strategies organisms use to acquire and use energy.

13. Primary Production Primary production : the amount of light energy that is converted to chemical energy Primary producers set a “spending limit” for the entire ecosystems energy budget Gross primary production (GPP) : total primary production in an ecosystem Net primary production (NPP) : the GPP minus the energy used by the primary producers for respiration (R a ) L/O: To describe the strategies organisms use to acquire and use energy.

14. Primary Production Satellite images show that different ecosystems have varying NPP What areas have higher NPP and why? L/O: To describe the strategies organisms use to acquire and use energy.

15. Secondary Production Secondary production : the amount of chemical energy in a consumer’s food that is converted to new biomass The transfer of energy between trophic levels is at around 10% efficiency

16. Matter Cycling Unlike energy, matter cycles through ecosystems Matter is found in limited amounts, unlike solar energy Biogeochemical cycles : nutrient cycles that contain both biotic and abiotic factors Water, carbon, nitrogen, and phosphorus cycle L/O: To describe the strategies organisms use to acquire and use energy.

17. Water Cycle Biological importance: water is essential for all life and influences the rate of ecosystem processes

18. Carbon Cycle Biological importance: carbon is essential for life and required in the formation of organic compounds

19. Nitrogen Cycle Biological importance: nitrogen is important for the formation of amino acids, proteins, and nucleic acids

20. Phosphorus Cycle Biological importance: phosphorus is important for the formation of nucleic acids, phospholipids, and ATP (energy)

21. Task: Create your own food web activity L/O: To describe the strategies organisms use to acquire and use energy. 20 marks

22. Plenary Fill in the blank: The transfer of energy between trophic levels is at around _____% efficiency What happens to the number and size of trophic levels if there is an increase in energy? What constantly supplies energy to ecosystems? True or false: energy is recycled throughout trophic levels Define primary production. L/O: To describe the strategies organisms use to acquire and use energy.

23. Behavioral Investigation – Isopods (Digital Lab) Isopods are a type of crustacean that can live in the sea, fresh water, or on land. In this investigation, you will test the Armadillidium vulgare’s reaction to different variables. Armadillidium vulgare are classifies as terrestrial crustaceans. L/O: To investigate an organism’s reactions to different variables.

24. An agricultural biologist was evaluating two newly developed varieties of wheat as potential crops. In an experiment, seedlings were germinated on moist paper towels at 20ºC for 48 hours. Oxygen consumption of the two-day-old seedlings was measured at different temperatures. The data are shown in the graph below. Starter: FRQ Practice Behavioural Investigation L/O: To investigate an organism’s reactions to different variables.