Terrestrial Ecology Ecology Energy Flow Ecosystem Structure Interactions Among Species Population Dynamics Reproductive Patterns

Ecology Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment. Figure 3-2

Ecology Ecosystem- A community of different species interacting together & with the chemical & physical factors making up its non-living environment. Species- groups of organisms that can mate and produce fertile offspring (5 to 100 million on earth). Population- A group of individual organisms of the same species living w/in a particular area. Communities- The population of all species living & interacting in an area. Habitat- The place where an organism or a population lives. Niche- The total way of life or role of a species in an ecosystem. All the physical, chemical, and biological conditions a species needs to live & reproduce in an ecosystem.

Ecology Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics. Figure 3-3

Energy Flow Ecosystems consist of nonliving (abiotic) and living (biotic) components that interact together Figure 3-10

Energy Flow Abiotic – nonliving parts of ecosystems (water, air, nutrients, solar energy) 1. Range of Tolerance – range of physical and chemical environments in which a species can survive.  Law of Tolerance: the abundance or distribution of an organism can be controlled by certain factors Tolerance Limits: The upper and lower limits to the range of particular environmental factors within which an organism can survive. Organisms with a wide range of tolerance are usually distributed widely, while those with a narrow range have a more restricted distribution.  

Lower limit of tolerance Upper limit of tolerance No organisms Few organisms Few organisms No organisms Abundance of organisms Population size Figure 3.11 Natural capital: range of tolerance for a population of organisms, such as fish, to an abiotic environmental factor—in this case, temperature. These restrictions keep particular species from taking over an ecosystem by keeping their population size in check. Zone of intolerance Zone of physiological stress Optimum range Zone of physiological stress Zone of intolerance Low Temperature High Fig. 3-11, p. 58

Energy Flow 2. Limiting Factor – abiotic factors that can limit or prevent the growth of a population. Limiting Factor Principle – too much or too little of any abiotic factor can limit or prevent the growth of a population.   Ex. Desert plants (water) Ex. Aquatic Ecosystems (temp, light, dissolved oxygen, nutrient availability, salinity)

Energy Flow Biotic – living parts of ecosystems (plants, animals, and microorganisms) biota. 1.Producers or Autotrophs (photosynthesis and chemosynthesis) Plants Some protists 2.Consumers or Heterotrophs a.      Herbivores b.      Carnivores (secondary or tertiary consumers) c.      Omnivores d.      Scavengers e.      Detritivores f.       Detritus feeders g. Decomposers

Energy Flow 3.Important Biotic Processes Cellular Respiration – removes oxygen from the environment and adds carbon dioxide and water. Anaerobic Respiration – can add methane gas, ethyl alcohol, acetic acid, and hydrogen sulfide to the environment. Photosynthesis– removes carbon dioxide and water from the environment and adds oxygen and water.

Energy Flow Producers- An organism that uses solar energy (green plant and some protists like algae) or chemical energy (some bacteria) to manufacture its food. First Trophic Level Basic source of all food but all energy comes from the sun Most producers capture sunlight to produce carbohydrates by photosynthesis:                                   

Energy Flow Biomass Biomass is dry weight of organic matter produced by plants & represents the chemical energy stored at each energy level. Stems, roots and leaves Can be used as electrical energy from wood, garbage & agricultural waste.

Primary Productivity of Ecosystems Energy Flow Primary Productivity of Ecosystems Productivity–the rate at which plants convert solar energy to biomass (NPP) Primary production- The conversion of solar energy to the energy of chemicals bonds during photosynthesis by autotrophs Secondary production- The total biomass that heterotrophs generate by consuming autotrophs Gross Primary Productivity- the energy that results when autotrophs convert solar energy to chemical energy High GPP- Shallow waters near continents Coral reefs Forests Low GPP Deserts Polar regions Open ocean  

Energy Flow Net Primary Productivity- what is left of GPP after it is used by an ecosystems producers to stay alive, grow and reproduce. - This is the energy or biomass available to consumers in an ecosystem. High NPP Estuaries Swamps and marshes Tropical rain forests Low NPP Open ocean Tundra Desert   The earth’s net primary productivity is the upper limit determining the planet’s carrying capacity for all consumer species. Our Share of Earth’s NPP 1)      We use, waste or destroy about 27% of earth’s NPP 2)      We use, waste or destroy about 40% of the NPP of terrestrial ecosystems

Energy Flow Net Primary Productivity Gross Primary Productivity GPP = NPP + Respiration Net Primary Productivity Respiration Gross Primary Productivity 99% of solar energy is reflected or passes through producers w/o being absorbed 1% of solar energy striking producers in captured by photosynthesis (GPP) 40% of GPP supports the growth and reproduction of producers (NPP)

Energy Flow Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Primary Consumers Second Trophic Level Herbivores- eat producers Omnivores- feed on both plant and animals. Secondary Consumers Third Trophic Level Carnivores- Primary consumers that eat other primary consumers Tertiary Consumers Fourth Trophic Level Carnivores that eat carnivores.

(decomposers and detritus feeders) First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Solar energy Heat Heat Figure 3.17 Natural capital: a food chain. The arrows show how chemical energy in food flows through various trophic levels in energy transfers; most of the energy is degraded to heat, in accordance with the second law of thermodynamics. Heat Heat Detritivores (decomposers and detritus feeders) Heat Fig. 3-17, p. 64

Energy Flow Scavengers- consume dead animals Detritivores- Specializes in breaking down dead tissues and products into smaller particles- insects Decomposers- Fungi and Bacteria that digests parts of dead organisms, cast-off fragments, and wastes of living organisms and recycles those nutrients back into the environment Detritus feeders- eat off of partially decomposing materials such as leaf liter, animal dung or plat debris

Energy Flow Decomposition As plant or animal matter dies it will break down and return the chemicals back to the soil. This happens very quickly in tropical rainforest which results in low-nutrient soils. Grasslands have the deepest and most nutrient rich of all soils

Energy Flow Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. Figure 3-19

Energy Flow 10% Rule We assume that 90% of the energy at each energy level is lost because the organism uses the energy. (heat) It is more efficient to eat lower on the energy pyramid. You get more out of it! This is why top predators are few in number & vulnerable to extinction.

Energy Flow Shows the decrease in usable energy available at each succeeding trophic level in a food chain or web.

Energy Flow Food Chains- determines how energy & nutrients move from one organism to another through the ecosystem Arrows – point from the producer to the consumer

Energy Flow Food Webs- Interconnected food chains that shows all possible energy transfers within an ecosystem