Ecosystems: Energy Flow

1. Ecosystems: Energy Flow

2. Objectives • Predict what would happen to an ecosystem if an energy source was removed (5.3.12.B.3) • A. Tracing the path that energy entering the ecosystems as sunlight follows when being transferred by producers into chemical energy through photosynthesis, and then being passed from organism to organism through food webs • B. Recognizing that living systems require a continuous input of energy to maintain their chemical and physical organizations and also understanding that with death (the cessation of energy input), living systems rapidly disintegrate • Investigate and describe the complementary relationship (cycling of matter and flow of energy) between photosynthesis and cellular respiration (5.3.12.B.5). • a. Analyzing and describing how the process of photosynthesis provides a vital connection between the sun and the energy needs of living systems

3. 6 Levels of Organization Biosphere: portion of Earth able to support life Biome: large group of ecosystems that share the same climate and have similar types of communities Ecosystem: all members of a community, along with their physical and chemical environments Community: Interacting populations that occupy the same geographic area at the same time Population: individual organisms of a single species that share the same geographic location at the same time Individual/Species: individuals capable of breeding with one another and producing fertile offspring

4. Ecosystems • Ecosystem: natural unit of living (biotic) and the non-living (abiotic) components with which they interact • Generally thought of in terms of: • Energy Flow • Food chains • Food webs • Display pyramidal relationships • Energy • Numbers • Biomass Our focus for today…

5. Energy Thermodynamics: study of energy Laws of Thermodynamics: First: Energy can be changed from one form to another, but cannot be created or destroyed (conservation of energy) Second: Energy systems tend to increase their entropy (disorder) Integral for organisms to continually consume energy to maintain their organization (as seen in energy flow relationships)

6. Energy Flow Relationships Activity

7. Questions 1. Where do all living things get energy from? 2. What is a producer? 3. What do the arrows mean? 4. What is a first order consumer? 5. What is a second order consumer? 6. What is a top order consumer? 7. What is a food web? 8. What is a food chain? 9. What does a food web tell us about life?

8. Food Chain Trophic structure: a hierarchy of feeding relationships which determines the pathways for energy flow Food chain: the sequence of organisms, each of which is a sources of food for the next Each member in the food chain feeds on the previoustrophic level Those organisms that obtain their food through the same number of links belong to the same trophic level There are commonly 4 links and seldom more than 6

9. Food Chain/Web • The primary energy source is the sun • Energy from the sun is fixed by producers in photosynthesis • Organisms that make their own food are called autotrophs • Producers make up the first trophic level in food chains

10. Food Chain/Web • Consumers must eat their source of energy and can not make their own food • Organisms that must eat their food are called heterotrophs • There are several trophic levels of consumers depending upon the ecosystem • Examples: • Primary/First Order Consumers • herbivores - vegetarians • Secondary/Second Order Consumers • carnivores – meat eaters • omnivores – both meat and veggies • Tertiary/Top Order Consumers

11. Food Chain/Web • Decomposers: organisms that obtain their nutrients from the breakdown (rather than ingestion) of dead organic matter • Detritus = dead organic matter • Examples of decomposers: bacteria, fungus • Decomposers themselves die. Their dead tissue is either broken down by other decomposers, fed on by detritivores, or accumulates in the water/soil.

12. Energy Flow Review Unidirectional Arrows show direction of energy flow through (biotic factors of) ecosystems Reliant upon predation consumption of one organism by another Driven by the sun’s energy sun provides continuous input of energy because energy can’t be recycled (matter can be recycled) photosynthesis Represented by Food Chains Food Webs

13. Ecological Efficiency Diagram: Energy Inputs and Outputs Does all of the energy leaving a trophic level get transferred to the next trophic level? Useful energy decreases as you move up the pyramid Amount of energy transferred is between 5-20% An average figure of 10% is used Therefore, at each link in a food chain, 90% of the sun’s energy is lost as heat

14. Ecological Efficiency Read excerpt from Cartoon Guide to the Environment Calculating ecological efficiency. Practice Problem: Draw an food chain made up of grass, a caterpillar, tiger, beetle, and snake (they are not in order). Assume 1,000 kJ of energy are available in the grass. At each stage, show how much energy is lost and how much is available to the next trophiclevel?

15. Ecological Efficiency Is energy transfer efficient?

16. Food Webs What would happen if you removed something from the chain or web? Select an organism to remove. How will it affect the other organisms in the web?

17. Food Webs What would happen if you added something to the chain or web? Select an organism to add. How will it affect the other organisms in the web?

18. http://www.teachersdomain.org/resource/tdc02.sci.life.eco.bioinvaders/http://www.teachersdomain.org/resource/tdc02.sci.life.eco.bioinvaders/ Invasive Species What is meant by the term invasive species? Why is the brown tree snake considered an invasive species? How does the brown tree snake end up in a new environment? What threats does the brown tree snake pose to naturally occurring species in these new environments? Why does the brown tree snake population thrive in new environments? What adaptations does the brown tree snake have that help it thrive?

19. Invasive Species • Non-native (or alien) to the ecosystem under consideration AND • Whose introduction causes or is likely to cause economic or environmental harm or harm to human health • Can be plants, animals, or other organisms • www.invasivespeciesinfo.gov • Article: Giant African Land Snails seized at Glasgow Airport http://www.bbc.co.uk/news/uk-scotland-glasgow-west-19648071

20. The Stink Bug! • The brown marmorated stink bug • Accidentally introduced to eastern PA, found in 1998 • An agricultural pest originally found in China, Japan, Korea, Taiwan • Now a pest in the US of fruit and other farm crops • Caused $37 million dollars in losses to apple farmers in the Mid Atlantic • http://ento.psu.edu/extension/factsheets/brown-marmorated-stink-bug

21. Ecosystems Generally thought of in terms of: • Energy Flow • Food chains • Food webs • Display pyramidal relationships • Energy • Numbers • Biomass Our focus for today…

22. Objectives • Use mathematical formulas to justify the concept of an efficient diet (5.3.12.B.2). • A. Explaining how food webs are limited and how pyramidal relationships exist. • B. Recognizing that all matter tends toward more disorganized states, and that living systems require a continuous input of energy to maintain their chemical and physical organizations • C. Calculating the trends in production, use and transfer of energy from one trophic level to another using data

23. Ecological Pyramids Graphical model of energy flow in a community. Energy: the energy content at each trophic level Biomass: the total dried mass of living matter at each trophic level Numbers: the number of individual organisms at each trophic level This type can be “inverted” Shapes shows amount of organisms or useful energy at each level

24. Lab: Building Eco. Pyramids Explore What is an owl pellet? Scientist’s study animal feces to learn what animals eat. Owls typically swallow their prey whole or in large pieces. Their stomach is found in 2 parts. The second part, the gizzard, compresses indigestible parts of their prey into matted pellets. They spit out the pellets through their mouth. If you only find part of an animal skeleton, count it as one entire animal. If you find an animal that is not listed, put it in the “Other” section on the data sheet. Estimate the weight based on the animal’s size relative to the known animals.

25. Lab: Building Eco. Pyramids Share findings with class. Record class data. Complete Lab.