Core Case Study: Tropical Rain Forests Are Disappearing  Cover about 2% of the earth’s land surface  Contain about 50% of the world’s known plant and animal species Disruption will have three major harmful effects  Reduce biodiversity  Accelerate global warming  Change regional weather patterns

Natural Capital Degradation: Satellite Image of the Loss of Tropical Rain Forest Fig. 3-1a, p. 54

The Earth’s Life-Support System Has Four Major Components  Atmosphere  Troposphere: where weather happens  Stratosphere: contains ozone layer  Hydrosphere  Geosphere  Biosphere

Fig. 3-2, p. 56 Soil Biosphere (living organisms) Atmosphere Rock Crust Mantle Geosphere (crust, mantle, core) Mantle Core Atmosphere (air) Hydrosphere (water)

© 2012 John Wiley & Sons, Inc. All rights reserved. Overview of Chapter 3  What is Ecology?  The Energy of Life  Laws of Thermodynamics  Photosynthesis and Cellular Respiration  Flow of Energy Through Ecosystems  Producers, Consumers & Decomposers  Ecological Pyramid  Ecosystem Productivity

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecology  I. What is Ecology? A. Ernst Haeckel developed the concept of ecology in the 19th century i. Ecology literally means “the study of one’s house”; it is the broadest field within the biological sciences, and is linked to many other disciplines (i.e., geology, earth science, chemistry, physics)

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecology  ii. It examines the systems that include interactions among organisms and between organisms and their abiotic environment 1. The biotic environment includes all living organisms 2. The abiotic environment includes living space, temperature, sunlight, soil, wind and precipitation

© 2012 John Wiley & Sons, Inc. All rights reserved. Major Biotic and Abiotic Components of an Ecosystem Fig. 3-6, p. 59

© 2012 John Wiley & Sons, Inc. All rights reserved.

Ecology Ecologists are most interested in the levels of biological organization that include or are above the level of the individual organism.

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecology cont….. i. A group of similar organisms whose members freely interbreed with one another in the wild to produce fertile offspring is termed a species ii.A population is a group of organisms of the same species that live in the same area at the same time iii.A natural association that consists of all the populations of different species that live and interact within an area at the same time is called a community. iv. A community and its physical environment comprise an ecosystem 1. An ecosystem is a system in which all of the biological, physical, and chemical components of an area form a complex, interacting network of energy flow and materials cycling 2. Ecosystem processes collectively regulate global cycles of water, carbon, nitrogen, phosphorus, and sulfur essential to the survival of humans and all other organisms

© 2012 John Wiley & Sons, Inc. All rights reserved. Fig. 3-5, p. 58 Parts of the earth's air, water, and soil where life is found Biosphere A community of different species interacting with one another and with their nonliving environment of matter and energy Ecosystem Populations of different species living in a particular place, and potentially interacting with each other Community PopulationA group of individuals of the same species living in a particular place OrganismAn individual living being The fundamental structural and functional unit of life Cell Chemical combination of two or more atoms of the same or different elements Molecule Smallest unit of a chemical element that exhibits its chemical properties Atom

© 2012 John Wiley & Sons, Inc. All rights reserved. Solar energy Chemical nutrients (carbon dioxide, oxygen, nitrogen, minerals) Heat Decomposers (bacteria, fungi) Producers (plants) Consumers (plant eaters, meat eaters) Heat

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecology cont…..  C.Landscape ecology is a subdiscipline of ecology  i.It studies ecological processes that operate over large areas  ii.A landscape is a region that includes several interacting ecosystems

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecology D.Ecologists who study the biosphere examine global interrelationships among Earth’s atmosphere, land, water, and organisms i. The parts of Earth’s atmosphere, ocean, land surface, and soil that contain all living organisms is termed the biosphere ii. The atmosphere is a gaseous envelope surrounding Earth iii. The hydrosphere is Earth’s supply of water iv. The lithosphere is the soil and rock of Earth’s crust

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy II.The Energy of Life A. Energy is the capacity or ability to do work i.Energy exists in several forms: chemical radiant, thermal, mechanical, nuclear, and electrical ii.Energy can exist as stored energy (potential) or as the energy of motion (kinetic)

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy B. The study of energy and its transformations is called thermodynamics i. In thermodynamics, the word system is used to refer to a group of atoms, molecules, or objects being studied 1. A closed system is self-contained and isolated; it does not exchange energy with its surroundings 2. An open system exhibits an exchange of energy with its surroundings

© 2012 John Wiley & Sons, Inc. All rights reserved. Thermodynamics ii. The first law of thermodynamics holds that energy cannot be created or destroyed, although it can change from one form to another iii. The second law of thermodynamics holds that when energy is converted from one form to another, some of it is degraded into heat, a less usable form that disperses into the environment 1. The less usable energy is more diffuse, or disorganized; entropy is a measure of this disorder or randomness 2. No process requiring an energy conversion is ever 100% efficient because much of the energy is dispersed as heat, resulting in an increase in entropy

© 2012 John Wiley & Sons, Inc. All rights reserved. Photosynthesis 6 CO H 2 O + radiant energy C 6 H 12 O H 2 O + 6 O 2 i.Photosynthesis is the biological process in which light energy from the sun is captured and transformed into the chemical energy of carbohydrate (glucose) molecules 2. bacteria, and algae perform photosynthesis 1.

© 2012 John Wiley & Sons, Inc. All rights reserved. Cellular Respiration C 6 H 12 O O H 2 O 6 CO H 2 O + energy ii.The chemical energy that plants store in carbohydrates and other molecules is released within cells of plants, animals, or other organisms through cellular respiration 1. In aerobic cellular respiration, molecules such as glucose are broken down in the presence of oxygen and water a. C6H12O6 +6O2 + 6H2O --> 6CO2 + 12H2O + energy 2. Anaerobic bacteria that live in waterlogged soil, stagnant ponds, or animal intestines respire in the absence of oxygen

© 2012 John Wiley & Sons, Inc. All rights reserved. Photosynthesis and Cellular Respiration

© 2012 John Wiley & Sons, Inc. All rights reserved. Other Type of Respiration  D.Chemosynthesis is the process by which energy produced from inorganic raw materials such as enzymes, hydrogen sulfide and oxygen; water and sulfur/sulfate are additional byproducts

© 2012 John Wiley & Sons, Inc. All rights reserved. Food Chains- The Path of Energy Flow  III.The Flow of Energy Through Ecosystems  A. Energy flow is the passage of energy in a one- way direction through an ecosystem  B. Producers, consumers, and decomposers

© 2012 John Wiley & Sons, Inc. All rights reserved. Food Web

© 2012 John Wiley & Sons, Inc. All rights reserved. Producers  i.Producers (aka autotrophs)  1. In photosynthesis, producers use the energy from sunlight to make organic molecules from carbon dioxide and water  2. Plants, algae and certain types of bacteria are important producers

© 2012 John Wiley & Sons, Inc. All rights reserved. Consumers  ii.Consumers (aka heterotrophs)  1. Consumers obtain energy when they eat producers or other consumers a. Consumers that eat producers are primary consumers (herbivores) b. Secondary consumers (carnivore) eat primary consumers c. Tertiary consumers (top carnivores) eat secondary consumers  2. Omnivores eat a variety of organisms  3. Detritus feeders (detritivores) consume organic matter that includes animal carcasses, leaf litter, and feces

© 2012 John Wiley & Sons, Inc. All rights reserved. Decomposers  iii.Decomposers (aka saprotrophs)  1. Wastes and dead organic material from producers and consumers supply decomposers (i.e., bacteria, fungi) with energy  2. Bacteria and fungi are important decomposers

© 2012 John Wiley & Sons, Inc. All rights reserved. Path of Energy Flow  C. The path of energy flow: who eats whom in ecosystems  i.In an ecosystem, energy flow occurs in food chains, in which energy from food passes from one organism to the next in a sequence 1. Energy enters ecosystems from an external source (the sun), flows linearly, and exits as heat loss

© 2012 John Wiley & Sons, Inc. All rights reserved. Path of Energy Flow cont. 2. Each level in a food chain is termed a trophic level a. Producers (photosynthetic organisms) form the first trophic level b. Primary consumers (herbivores) form the second trophic level c. Secondary consumers (carnivores) form the third trophic level d. Decomposers occur at every step in a food chain  ii. Simple food chains rarely occur in nature, a food web is a more realistic model

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecological Pyramids D. Ecological pyramids i. Ecological pyramids graphically represent the relative energy values of each trophic level 1. A pyramid of numbers show the number of organisms at each trophic level in a given ecosystem 2. A pyramid of biomass illustrates the total biomass at each successive trophic level a. Biomass is a quantitative estimate of the total mass of living material b. Biomass indicates the amount of fixed energy at a particular time 3. A pyramid of energy illustrates the energy content, often expressed as kilocalories per square meter per year, of the biomass at each trophic level

© 2012 John Wiley & Sons, Inc. All rights reserved. Pyramid of Numbers  Illustrates the number of organisms at each trophic level  Fewer organisms occupy each successive level  Does not indicate:  biomass of organisms at each level  amount of energy transferred between levels

© 2012 John Wiley & Sons, Inc. All rights reserved. Pyramid of Biomass  Illustrates the total biomass at each successive trophic level  Biomass: measure of the total amt of living material  90% reduction in biomass through trophic levels

© 2012 John Wiley & Sons, Inc. All rights reserved. Pyramid of Energy  Illustrates how much energy is present at each trophic level and how much is transferred to the next level  Most energy dissipates between trophic levels  Explains why there are so few trophic levels

© 2012 John Wiley & Sons, Inc. All rights reserved. Ecosystem Productivity E. Gross Primary Productivity (GPP)  Total amount of energy that plants capture and assimilate in a given period of time  Net Primary Productivity (NPP)  Plant growth per unit area per time  Represents the rate at which organic material is actually incorporated into the plant tissue for growth  GPP – cellular respiration = NPP  Only NPP is available as food to organisms

© 2012 John Wiley & Sons, Inc. All rights reserved. Variation in NPP by Ecosystem

© 2012 John Wiley & Sons, Inc. All rights reserved. Human Impact on NPP  Humans represent 0.5% of land-based biomass, but use 32% of land-based NPP!  This may contribute to loss of species (extinction)  This represents a threat to planet’s ability to support both human and non-human inhabitants