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Chapter 4 Ecosystems & Energy Ecology  The branch of biology that deals with the interactions between organisms and the relationship between organisms.

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Presentation on theme: "Chapter 4 Ecosystems & Energy Ecology  The branch of biology that deals with the interactions between organisms and the relationship between organisms."— Presentation transcript:



3 Chapter 4 Ecosystems & Energy

4 Ecology  The branch of biology that deals with the interactions between organisms and the relationship between organisms and the environment.

5 Do Now:  Draw a flow chart to represent the organizational relationships between the following terms from the most inclusive to the least inclusive: ecosystem, population, species, community, and biosphere.

6 Levels of Biological Organization

7 Levels of Organization  Cellular Organization –Cells –Tissues –Organs –Organ Systems –Organisms –SPECIES  Ecosystem Organization –Species –Population –Community –Ecosystem –Landscape –Biosphere

8 Species  A group of organisms capable of producing more members of the same organism.. Homo sapiens with Homo sapiens Not Homo sapiens with Homo habilus

9 Species The Brown Trout Salmo trutta

10 Population  Includes all the members of a species found in a given area.  Ex: sunfish in a pond

11 Community  Includes all the populations in a given area.  Ex: all plants, animals, and microorganisms make up a pond community

12 Ecosystem  Includes all the members of the community plus the physical environment in which they live in. –Interaction of biotic and abiotic factors

13 Abiotic Factors  Nonliving factors.  The abiotic factors of an ecosystem include the physical and chemical factors that affect the capacity of an organism to live and reproduce. These factors are: 1. Intensity and duration of light 2. Temperature range 3. Amount of moisture 4. Type of substrate 5. Availability of inorganic substances and gases 6. pH

14 Biotic Factors  Living factors  These factors directly or indirectly affect the environment.  Thus, the organisms, their presence, parts, interaction, and wastes all act as biotic factors.  These interactions include: 1. Nutritional relationships 2. Symbiotic relationships

15 Requirements for a Stable Ecosystem  The ecosystem involves interactions between living and nonliving things. Certain requirements must be met for a stable ecosystem to exist: 1.There must be a constant supply of energy (sunlight for photosynthesis). 2.There must be living organisms that can incorporate the energy into organic compounds (food). 3.There must be a recycling of materials between organisms and the environment.

16 Limiting Factors  Determines the types of organisms which may exist in that environment.  Examples are: 1.A low temperature common to northern latitudes determines in part what species of plants can exist in that area. 2.The amount of oxygen dissolved in a body of water will help determine which species of fish will exist there.

17 Landscape  A spatially heterogeneous region that includes several interacting ecosystems  Connections among ecosystems found in a particular area.

18 Biosphere  The portion of the earth in which life exists.  The biosphere is composed of many complex ecosystems that include water, soil, and air.

19 Ecological Organization Population ( or ) Community ( + + ) Ecosystem ( ) Biosphere ( )

20 Do Now:  Compare and contrast potential energy and kinetic energy using biological or ecological examples and references

21 Types of energy  Energy: the capacity or ability to do work.  Potential Energy: Stored energy.  Kinetic Energy: The energy of motion.

22 Do Now:  Define energy and briefly describe how the different forms contribute to the continual energy needs of organisms

23  Heat Energy: thermal energy that flows from an object with a high temp. (heat source) to an object with a lower temp. (heat sink). Types of energy

24  Nuclear Energy: energy found within atomic nuclei.

25 Types of Energy  Electrical Energy: energy that flows as charged particles.

26 Thermodynamics: The study of energy & its transformations. 1 st Law of Thermodynamics: energy cannot be created nor destroyed, but it can be transformed. 2 nd Law of Thermodynamics: when energy is converted some usable energy is degraded into a less usable form. (Entropy)

27 Do Now:  Cellular respiration occurs in both plant and animal cells while photosynthesis only occur in plant cells. How are plant and animals connected via these two processes? Be sure to include balanced chemical equations as part of your answer.

28 Closed and Open Systems Earth is an open system because it receives energy from the sun.

29 Types of Energy Potential Energy Mechanical (Kinetic) Energy Heat Energy Nuclear Energy Electrical Energy Chemical Energy Radiant (Solar)

30 Energy Flow Relationships  For an ecosystem to be self- sustaining, there must be a flow of energy between organisms.  The pathway of energy flow through the living components of an ecosystem are represented by food chains and food webs.

31 Nutritional Relationships  Involves the transfer of nutrients from one organism to another within an ecosystem.  In terms of nutrition, organisms are either autotrophs or heterotrophs  SEE OWL LAB

32 Energy Flow through a food Chain

33 Energy Losses  The mouse receives energy from the food it eats.  Cells extract the food's energy for growth, acquiring food, escaping enemies lost as heat. Some lost in the mouse's waste (feces).  The remaining energy is stored in the mouse's body and is available to the organism that preys on it.  About 90% of the energy is used or lost, only 10% is available to predators.

34 Energy Flow

35 Biological Magnification  A nondegradable or slowly degradable substance  That becomes more and more concentrated in the tissues of organisms at higher trophic levels of a food web. –* Dichloro-Diphenyl-Trichloroethane (DDT) –* Polychlorinated biphenyls (PCBs)

36 DDT in Food Webs

37 DDT

38 PCBs in Food Webs  PCB concentrations in animal tissue can be magnified up to 25 million times.  Microscopic organisms pick up chemicals from sediments  Consumed in large numbers by filter feeding zooplankton.  Mysid shrimp then consume zooplankton  fish eat the mysid  and so on up the food web to the herring gull.  (Figure and caption from Our Stolen Future, p. 27)

39 DDT Detection  In 1962, Rachel Carson, a former U.S. Fish and Wildlife Service (USFWS) scientist and writer, published Silent Spring, outlining the dangers of DDT Fig. 41-8, p.736

40 Do Now:  Discuss the contributions of saprotrophs and detritivores to a balanced ecosystem.  Identify two representatives of each group in your discussion

41 (A) Food Chains  Green plants and other photosynthetic organisms are the organisms in an ecosystem that can convert radiant energy from sunlight into food.  A food chain involves the transfer of energy from green plants through a series of organisms with repeated stages of eating and being eaten.

42 Food Chain

43 (B) Food Webs  In a natural community, most organisms eat more than one species and may be eaten, in turn, by more than one species.  Thus, the various food chains in a community are interconnected forming a food web.  SEE OWL LAB

44 Food Web at the Edge of an Eastern Deciduous Forest

45 Do Now:  Define and discuss three applications of the term: ecological pyramid.  What accounts for the shape of the pyramid?  Use sketches of each type of pyramid with associated quantitative units to support your comparison.

46 (C) Pyramid of Energy  The greatest amount of energy in a community is present in the organisms that make up the producer level.  Only a small portion of this energy (10%) is passed on to primary consumers, and only a smaller portion (10% of the original 10%) is passed on to secondary consumers.  A pyramid of energy can be used to illustrate the loss of usable energy at each feeding level.



49 B. ALL living organisms must carry out ALL 8 life functions Nutrition Transport Respiration Excretion Synthesis Growth Regulation Reproduction

50 Autotroph  An organism capable of making their own food –Photosynthetic –Chemosynthetic

51 Chemosynthesis  A type of autotrophic nutrition  Does not require light as an energy source  Energy is obtained by chemical reactions within the cell  Example: Hydrothermal vent bacteria

52 Photosynthesis  The most common type of autotrophic nutrition  In this process, organisms use energy from sunlight, carbon dioxide, and water to make food (usually glucose)

53 Chloroplast  Contains pigments called: –chlorophylls (a & b greens) –Xanthophylls (yellow) –Carotenes (orange)  It is in the chloroplast that light energy is trapped by chlorophylls and glucose is formed as the product. (food)

54 Structure of Chloroplast

55  Which Wavelengths are the best for photosynthetic plants?  Which Wavelength is the worst? Absorption of Light by Chlorophyll a and Chlorophyll b VBGYOR Chlorophyll b Chlorophyll a Wavelengths effects on Photosynthesis

56 ROY G BIV  The maximum amount of photosynthesis will occur when exposed to red and blue light because it is these two colors that are easily absorbed in great quantity by the chlorophyll  For green leaves, green light is reflected and therefore has the least affect on photosynthesis

57 Formula for Photosynthesis 6CO H 2 O + radiant energy  C 6 H 12 O 6 + 6H 2 O + 6O 2 C 6 H 12 O 6 + 6O 2 + 6H 2 O  6CO H 2 O + work energy Formula for Cellular Respiration

58 Photosynthesis and Cellular Respiration

59 Photosynthesis occurs in two stages: 1. Light Reaction 2. Dark Reaction

60 Structure of Chloroplast Light reactions Dark reactions

61 Chloroplast water O2O2 Sugars CO 2 Light- Dependent Reactions Calvin Cycle NADPH ATP ADP + P NADP + Sunlight Section 8-3 6CO H 2 O + radiant energy  C 6 H 12 O 6 + 6H 2 O + 6O 2 Photosynthesis: An Overview

62 1. Light Reaction 1. Occurs in the grana of the chloroplast. 2. First stage of photosynthesis. 3. Begins with the absorption of light energy by chlorophyll. 4. Photolysis occurs- a reaction in which H 2 O molecules split into oxygen and hydrogen. 5. All oxygen given off during photosynthesis comes from the photolysis of water. 6. ATP (Adenosine triphosphate), which is a form of chemical energy, is produced.

63 Chloroplast (H 2 O) Oxygen (6O 2 ) I am out of here! Light Reaction 12 WATE R molecules 12 WATE R molecules 12 Hydrogen (This all occurs In the Grana.) 12 Hydrogen NADPH + ATP AKAPhotolysis

64 Dark Reaction “Calvin Cycle” “Light Independent Reaction” 12 Hydrogen 6(CO 2 ) NADPH+ATP C 6 H (H 2 0) AKA Glucose (This all occurs in the Stroma.) Carbon Fixation

65 The Food Factory


67 2. Dark Reaction  Occurs in the stroma of the chloroplast.  The second stage of photosynthesis.  It is here that CO 2 is converted to carbohydrates by a process called carbon fixation. CO 2  PGAL  C 6 H 12 O 6  Light is not required.  The dark reaction requires ATP from the light reaction for it to take place.

68 Factors Affecting the Rate of Photosynthesis 1. Light Intensity 2. Water 3. Carbon dioxide level 4. Temperature

69 Adaptations for Photosynthesis A. Unicellular Organisms 1. Almost all chlorophyll-containing unicellular organisms are aquatic. (live in water) 2. The raw materials for photosynthesis are absorbed directly from the water and into the cell Ex: algae & cyanobacteria

70 Adaptations for Photosynthesis B. Terrestrial Plants (land-dwelling) 1. Occurs in leaves that provide the maximum surface area for the absorption of light.

71 Plants  Leaves- have stomates for gas exchange  Stems- have lenticels for gas exchange –Roots- gas exchange occurs across a moist membrane of root hairs (diffusion)

72 Do Now:  Briefly explain the process of cellular respiration and uses of the energy obtained from the process. Your answer should include the following terms: glucose, water, carbon dioxide, chemical energy, and oxygen. What organisms carry on this process?

73 Glucose (C6H12O6) 2 pyruvic acid 2 ATP 2 PGAL (C3H5O3) Glycolysis (splitting glucose) +4 ATP Net Gain:???

74 Glycolysis (splitting glucose)  Net Energy Yield from Glycolysis  Energy requiring steps: –2 ATP invested  Energy releasing steps: –2 NADH formed –4 ATP formed  Net yield is 2 ATP and 2 NADH

75 Glycolysis (splitting glucose) All three reactions with Glycolysis  Glycolysis occurs in cytoplasm  Reactions are catalyzed by enzymes Glucose2 Pyruvate (six carbons) (three carbons)

76 Aerobic Respiration Glucose + O 2  H 2 O + CO ATP’s  Again, enzymes are used and a net of 36 ATP’s are produced Equations for Anaerobic Respiration Equations for Anaerobic Respiration 1. Lactic Acid Fermentation glucose  2 lactic acids + 2 ATP’s 2. Alcoholic Fermentation glucose  2 alcohol + 2 CO ATP’s In each equation, enzymes are used and a net gain of 2 ATP’s are produced

77 Equations for Anaerobic Respiration glucose  2 lactic acids + 2 ATP’s glucose  2 alcohol + 2 CO ATP’s  In each equation, enzymes are used and a net gain of 2 ATP’s are produced

78 Equation for Aerobic Respiration glucose + O 2  H 2 O + CO ATP’s Again, enzymes are used and a net of 36 ATP’s are produced

79 Who am I?

80 Do Now:  What is the human impact on net primary productivity? What are the potential environmental problems associated with this impact and what changes would be required to minimize human impact?

81 Net Primary Productivity (NPP) = Gross Primary Productivity (GPP) (total energy from photosynthesis /unit area/time) - Plant respiration (energy invested by plants)

82 (NPP) = GPP (rate) – Plant Respiration Humans compete with other species for energy. Our planet cannot handle the burden from human overpopulation. Total energy produced Energy cost

83 Humans compete with other species for energy. Our planet cannot handle human overpopulation. Table 9l-1: Average annual Net Primary Productivity of the Earth's major biomes. Ecosystem Type Net Primary Productivity (kilocalories/meter 2 /year) Tropical Rain Forest 9000 Estuary 9000 Swamps and Marshes 9000 Savanna 3000 Deciduous Temperate Forest 6000 Boreal Forest 3500 Temperate Grassland 2000 Polar Tundra 600 Desert < 200

84 There are 3 basic organisms in a food web: 1)Producers 2)Consumers 2a) Primary consumers 2b)Secondary consumers 3)Decomposers


86 There are 3 basic organisms in a food web: 1. Producers- include green plants and other photosynthetic organisms that synthesize the organic nutrients that supply energy to other members in the community.

87 Question  Briefly discuss the role of autotrophs in an ecosystem

88 There are 3 basic organisms in a food web: 1. Consumers- include all heterotrophic organisms. Organisms that feed on green plants are primary consumers, or herbivores. Secondary consumers, or carnivores, feed on other consumers. Omnivores eat producers and consumers.

89 There are three basic classes of organisms in a food web: Decomposers – are the organisms (saprotrophs) that break down wastes and dead organisms so that chemical materials are returned to the environment for use by other living organisms.

90 Antarctic food web

91 Krill!

92 Do Now:  What are krill? Using appropriate terminology, discuss the role of krill in the Antarctic food web, and describe what has been happening to the population of these animals over that past 150 years and why. What has been the impact on this Antarctic ecosystem of human related change in the global environment?

93 Do Now:  Today, commercial fishermen are “fishing down the food web.” This is unsustainable. WHY? How can this movement down the marine food web be reversed?

94 D-End

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