Principles of Ecology Ecology – study of relationships between living and nonliving parts of the world Ernst Haeckel (1866) – first to use the word to name the study of how organisms fit into their environment

Exam Need to Know Material Levels of organization from molecules to biosphere: How do ecologists study the living world around them? Members of food chains – trophic levels (ie: producers, decomposers, detritivores etc…) Biomagnification, carrying capacity, limiting factors Food Chains vs Food Webs Ecological pyramid types Autotrophs vs heterotrophs- different types Water cycle Nitrogen cycle Phosphorous cycle Carbon cycle Abiotic vs biotic Symbiotic relationships – parasitism, commensalism, mutualism Predator vs prey Biodiversity benefits Characteristics of Minnesota Ecosystems

Parts of the Environment Abiotic factors – non-living parts of an organism’s environment –Air currents, temperature, moisture, light, soil Biotic factors – all the living things that inhabit the environment

Levels of Organization Organism Population Community Ecosystem Biosphere Biome

Niche vs. Habitat vs. Ecosystem Ecosystem – all the organisms in a given area and the abiotic factors that affect them Habitat – place an organism lives out its life Niche – role and position a species has in its environment –Includes all biotic and abiotic interactions as an organism meets its needs for survival –If two species are competing for the same niche, one will most likely drive the other out and take control of the niche. What is your niche?

Niche vs. Habitat vs. Ecosystem An egret lives around Lura Lake which is part of the Maple River Watershed. The egret and its mate eat fish, frogs, salamanders, snakes, crayfish, mice, aquatic insects, crickets, grasshoppers, and a variety of other insects in Lura Lake and build a nest in a tree along side the lake. What is the egret’s habitat? What is the egret’s niche? What is the egret’s ecosystem?

Relationships All living things form relationships with other living things Symbiotic Relationship – a relationship between organisms of two different species that live together in direct contact

Commensalism One organism benefits – The other is not affected –Examples –Spanish moss on a tree –Barnacles on a whale –Burdock seeds on a passing animal

Mutualism Both organisms benefit –Acacia tree and ants (Pseudomyrmex sp.) – tree provides food for the ants and the ants protect the tree from animals that would eat the leaves –Lichens: algae and fungus living together. Algae provides food (photosynthesis) and the fungus provides protection and attaches the lichen to the rock or wood where it lives.

Parasitism One organism benefits, the other is harmed –Some live with in the host Tapeworms Heartworms Bacteria –Some feel on the external surface of the host Ticks Fleas Mistletoe –Most do not kill their host (at least not quickly)

Ecosystem Requirements #1 - Continuous supply of Energy #2 – A flow of energy from one population to another

Obtaining Energy Autotrophs - use energy from the sun or energy stored in chemical compounds to produce energy Heterotrophs – must consume their energy –Herbivores –Carnivores –Omnivores –Detritivores –Scavengers –Decomposers

Herbivores Eat plants (autotrophs)

Carnivores Eat other heterotrophs –Predators – kill their own food –Scavengers – eat animals that are already dead

Omnivores Eat both autotrophs and heterotrophs (plants and animals)

Detritivore A type of decomposer – eats decaying matter and return nutrients to soil, water, and air –Ex. worms, millipedes, woodlice, dung flies, and slugs

Decomposers They break down the dead organisms through decomposition and return nutrients to soil, water, and air -Ex. Fungus and bacteria

Energy Flows through an Ecosystem in a Complex Network of Feeding relationships called a FOOD WEB.

Food Chain

Energy Pyramid The energy pyramid is made of several trophic levels A Trophic Level (or feeding level) is a group of organisms whose feeding source is the same number of steps from the Sun. –Primary Producers (Autotrophs) are the First Trophic Level. –Primary Consumers (Herbivores) are the Second Trophic Level. –Secondary and Tertiary Consumers (Carnivores and Omnivores) are the Third and Fourth Trophic Levels. –Most Animals feed at more than one Trophic Level.

Trophic Levels Energy is Lost or Used as it Flows through the Trophic Levels of an Ecosystem. Producers (Plants) absorb Energy from the Sun, but only about ½ of the Energy capture from the Sun becomes part of the Plants Body. The other ½ is used for Living and Growing or Lost as HEAT. At each Trophic Level, the Energy stored in an organism is about 1/10 that of the Level Below it. (10%).

Trophic Levels Because Energy diminishes at each successive Trophic Level, Few Ecosystems can contain more than 4 or 5 Trophic Levels. Organisms at Higher Trophic Levels, Large Carnivores, tend to be Fewer in number than those at Lower Trophic Levels, Producers.

Number and Biomass Pyramids The number of organisms at each trophic levels decreases as you step up the pyramid. Biomass (living organic matter) is reduced at each trophic level as well

Bioaccumulation/ Biomagnification Energy is not the only thing that is passed along through the food web. If contaminants are introduced at any level, those organisms that consume the contaminated food, will absorb the contaminants as well. Because the amount of energy required gets higher at each level, those organisms have to consume more and thus can accumulate higher levels of the contaminants in their bodies – bioaccumulation. Example – A pesticide that you put of your yard is consumed by the grasshoppers that live there. The partridge eats 10 grasshoppers. The hawk eats 3 partridges. –If the grasshopper consumed 1 mg of the pesticide, the partridge ingested 10mg, and the hawk consumed 30mg.

Geochemical Cycles Geochemical Cycles are the movement of a particular form of matter through the living and nonliving parts of an ecosystem Since Earth is a closed system, it must continually cycle its essential matter. Matter changes form but is neither created nor destroyed; it is used over and over again in a continuous cycle. Organisms are an important part of this cycling system. Matter placed into biological systems is always transferred and transformed. Matter, including carbon, nitrogen, and water, gets cycled in and out of ecosystems.

Carbon Cycle Carbon is one of the major components of the biochemical compounds of living organisms (proteins, carbohydrates, lipids, nucleic acids). Carbon is found in the atmosphere and also in many minerals and rocks, fossil fuels (natural gas, petroleum, and coal) and in the organic materials that compose soil and aquatic sediments. Organisms play a major role in recycling carbon from one form to another in the following processes: –Photosynthesis –Respiration –Decomposition –Conversion of biochemical compounds

Carbon Recycling Processes Photosynthesis: Autotrophs take in carbon dioxide from the atmosphere and convert it to simple sugars. Respiration: Organisms break down glucose and carbon is released into the atmosphere as carbon dioxide.

Carbon Recycling Processes Decomposition: When organisms die, decomposers break down carbon compounds which both enrich the soil or aquatic sediments and are eventually released into the atmosphere as carbon dioxide. Conversion of biochemical compounds: Organisms store carbon as carbohydrates, proteins, lipids, and nucleic acids in their bodies. When animals eat, those compounds can be: –used for energy –converted to compounds that are suited for the predator’s body –released to the atmosphere as methane and other gases

Carbon Recycling Processes Other methods of releasing stored carbon may be: –Combustion: When wood or fossil fuels (which were formed from once living organisms) are burned, carbon dioxide is released into the atmosphere. –Weathering of carbonate rocks: Bones and shells fall to the bottom of oceans or lakes and are incorporated into sedimentary rocks such as calcium carbonate. When sedimentary rocks weather and decompose, carbon is released into the ocean and eventually into the atmosphere.

Nitrogen Cycle Nitrogen is the critical component of amino acids which are needed to build proteins in organisms. Nitrogen is found in the atmosphere as elemental nitrogen (N 2 ), in living organisms (in the form of proteins and nucleic acids), or in organic materials that compose soil and aquatic sediments. Organisms play a major role in recycling nitrogen from one form to another in the following processes: –Nitrogen-fixation –Intake of nitrogen into the organisms –Decomposition –Denitrification

Nitrogen Recycling Processes Nitrogen-fixation: Nitrogen-fixing bacteria, which are found in the soil, root nodules of plants, or aquatic ecosystems, are capable of converting nitrogen found in the air or dissolved in water into the forms that are available for use by plants. Intake of nitrogen into the organisms: Plants take in the nitrogen through their root systems in the form of ammonia or nitrate and in this way, nitrogen can enter the food chain.

Nitrogen Recycling Processes Decomposition: When an organism dies or from animal waste products, decomposers return nitrogen to the soil. Denitrification: Denitrifying bacteria break down the nitrogen compounds in the soil and release nitrogen into the atmosphere.

Water Cycle Water is a necessary substance for the life processes of all living organisms. Water is found in the atmosphere, on the surface of Earth and underground, and in living organisms. The water cycle, also called the hydrologic cycle, is driven by the Sun’s heat energy, which causes water to evaporate from water reservoirs (the ocean, lakes, ponds, rivers), condense into clouds, and then precipitate back to water bodies on Earth. Organisms also play a role in recycling water from one form to another by: –Intake of water into the organisms –Transpiration –Respiration –Elimination –Percolation

Water Recycling Processes Intake of water into the organisms: Organisms take in water and use it to perform life functions (such as photosynthesis or transport of nutrients). Transpiration: Plants release water back into the atmosphere through the process of transpiration (the evaporative loss of water from plants). Respiration: All organisms metabolize food for energy and produce water as a by-product of respiration. Elimination: Most organisms need water to assist with the elimination of waste products.

Phosphorus Cycle a) It is the main constituent of energy rich compounds like ADP (Adenosine diphosphate) and ATP (Adenosine triphosphate) b) It’s a major constituent of cell membrane, nucleic acid, cellular energy transfer systems. c) Essential for metabolic reactions releasing energy. d) Required for encoding of the information in genes (as it is the component of nucleotides and nucleic acids). Phosphorus has no gaseous phase and hence forms a part of sedimentary cycle

Maintaining Ecosystems All of the Earth’s processes help ecosystems maintain our biosphere Our biosphere is the inhabited portion of our planet made up of three parts: –Atmosphere –Hydrosphere –Geosphere Each of these systems must interact efficiently for each ecosystem to be maintained

Atmosphere Our atmosphere is primarily composed of materials from life’s processes. Oxygen –Plants and other autotrophs produce enough oxygen for themselves and other organisms through photosynthesis –The oxygen from photosynthesis is also responsible for the ozone layer which prevents the sun’s UV radiation from reaching the Earth’s surface Carbon Dioxide –Oxygen is used by plants and animals for cellular respiration which releases carbon dioxide into the atmosphere –The processes of photosynthesis and cellular respiration help keep the concentrations of oxygen and carbon dioxide balanced.

Atmosphere Nitrogen –Nitrogen in the atmosphere is maintained by the Nitrogen cycle Water –Water vapor in the atmosphere is maintained by the water cycle –As water vapor condenses in the atmosphere, impurities (dust, particulates, etc) are removed from the atmosphere and fall to Earth with precipitation. Thus, the air is cleaned after a rain or snow fall.

Atmosphere Imbalance The greenhouse effect is the normal warming effect when gases (such as carbon dioxide, oxygen, methane, and water vapor) trap heat in the atmosphere. The amount of carbon dioxide in the atmosphere cycles in response to how may plants and other photosynthetic organisms cover Earth and how much carbon dioxide they absorb. The amount of carbon dioxide in the atmosphere also cycles in response to the degree to which oceans cover Earth. The salt water of oceans acts as a sink for carbon dioxide, absorbing what plants do not use and converting it to various salts such as calcium carbonate.

Hydrosphere The hydrologic cycle is maintained by the energy of the Sun and the effect of weather. The hydrologic cycle purifies water in several ways: –Evaporated water is pure water containing no impurities. –As water seeps down through the soil and rock it is physically filtered of impurities. –As water flow slows, heavier particles of sediment settle out, leaving purified water to travel toward the oceans.

Geosphere As part of the geosphere, the soils on Earth are constantly being generated and eroded. All soils are composed of four distinct components – inorganic minerals, organic matter, water, and air. As the weathering of inorganic materials from wind, water, and ice and the decaying of organic materials continue, more soil is produced. Soil erosion and deposition are natural processes that move soil from one location to another due to water, wind, ice and other agents. In most areas, the presence of plants allows the process of soil production to be consistent with the process of soil erosion so that the overall amount of soil remains constant. The presence of soil in an ecosystem allows for succession to take place.