2. Chapters 3 & 4

3.  Anchor: BIO.B.4.2: Describe interactions and relationships in an ecosystem ◦ BIO.B.4.2.1: Describe how energy flows through an ecosystem

4.  For life to continue within the ecosystem, three things must be present ◦ 1. The SUN ultimately provides nearly all energy on earth! ◦ 2. The cycling of both matter and nutrients. ◦ 3. Gravity helps to hold everything in place, including the atmosphere and helps to move nutrients through their cycles Fungi

5.  All things in an ecosystem can be classified as: ◦ Biotic: anything living (or once living)  Ex: ◦ Abiotic: anything nonliving (never alive)  Ex:

6.  Classification of Organisms ◦ Producers/Autotrophs: make their own food, usually through photosynthesis  Ex:

7.  Chemosynthesis: producers create food in the absence of light using hydrogen sulfide ◦ Ex: bacteria that live at deep sea vents

8.  Consumers/Heterotrophs: cannot make their own food ◦ Herbivores: feed on plants/producers  Also called primary consumers  Ex:

9. ◦ Carnivores: feed on other animals  Secondary Consumers: feed on primary consumers  Ex:  Tertiary Consumers: feed on secondary consumers  Ex:

10. ◦ Omnivores: eat both producers and consumers  Ex: raccoon, bears, rats

11. ◦ Detritivore Consumers: feed only on DETRITUS  Detritus: parts of dead organisms, wastes of organisms  Ex: earthworms, crabs, ants ◦ Decomposers: break down organic matter so that it can be recycled  Ex. Bacteria, fungi

12.  How does energy MOVE through ecosystems? ◦ Energy moved in the form of “food” or organic matter ◦ Remember, energy can only flow in ONE direction  From the sun  producers  consumers

13.  Food chain: a series of steps where organisms transfer energy by eating and being eaten ◦ Ex: ◦ What are the limitations of a food chain?  Very simple/limited – doesn’t show all food connections in an ecosystem

14.  Food Webs: multiple linked food chains demonstrating the complex interactions in communities ◦ Ex:

15.  Trophic Levels: each step in a food chain or web ◦ Ex:  Producers = 1 st trophic level  Consumers = 2 nd, 3 rd, 4 th trophic levels

16. Fig 6.3 © 2005 John Wiley and Sons Publishers

17. Fig 6.4 © 2005 John Wiley and Sons Publishers

18. Fig 6.5 © 2005 John Wiley and Sons Publishers

19. Fig 6.6 © 2005 John Wiley and Sons Publishers

20.  Trophic Levels: ◦ Each consumer depends upon the trophic level below it for all energy!  Only 10% of the energy is transferred from level to level  The other 90% is used by the organisms for metabolism (respiration, movement, reproduction, growth) and given off as body heat

21. sun secondary consumers (carnivores) primary consumers (herbivores) producers (plants) loss of energy

22. only this energy moves on to the next level in the food chain 17% growth 50% waste (feces) 33% cellular respiration energy lost to daily living

23.  Ecological Pyramids: illustrate the relative amounts of energy or matter contained within each trophic level 1,000,000,000 100,000 100 1 Numbers

24.  Energy Pyramids: illustrates the amount of energy (organic material), usually in kCals or Joules (J), available

25.  Biomass Pyramids: illustrates the total amount of living tissue in a trophic level, usually in g/unit area

26.  Numbers Pyramid: illustrates the actual number of individual organisms in each trophic level