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ecology a look at the basics Ecology – The study of the interactions of the living and non-living world. Ecology terms/groupings Species—one kind of organism; similar in structure and able to pass these traits on to offspring. Population—all the members of a species living in a given geographic area. Community—all of the populations in an area; i.e., all of the living things. Ecology terms/groupings Ecosystem—the interaction of the community with the non-living environment Biome—a group of ecosystems that have the same climate & similar biological communities; ex.—grassland, desert, wetland, tropical rainforest, &c. Biosphere—all the parts of the planet in which life exists. www.eoearth.org biosphere Dynamic!! Extends from about 6 mi below surface to 5 mi above (discontinuous) About 0.0007% of the Earth by volume About 0.00008% of the Earth by mass the biosphere https://montagepages.fuselabs.com = peel Unique Ecosystems Biotic factors – the living part of the ecosystem. Geese Plankton People Trees Fungi bacteria Ecosystems Abiotic factors – the non living parts of the ecosystem. Air Sand Water Temperature Wind Sunlight pollutants Ecology The main point is how energy moves through the ecosystem. Energy in Ecosystems Energy from the Sun is the major source for all living things. The process of photosynthesis traps it so it can be used by living organisms. Energy is NOT recycled throughout the ecosystem Ecology Organisms can be producers or consumers Producers (autotrophs)—convert energy from the environment into carbon bonds such as those found in glucose chemicals Plants Algae Cyanobacteria Deep sea bacteria photosynthesis chemosynthesis Electromagnetic spectrum http://www.antonine-education.co.uk/physics_gcse/Unit_1/Topic_5/topic_5_what_are_the_uses_and_ha.htm Pigment absorption across the visible spectrum PHOTOSYNTHESIS sunlight Carbon dioxide glucose water Sunlight + 6 CO2 + H2O oxygen C6H12O6 + 6 O2 photosynthesis Sunlight energy used to form C-C bonds in the form of sugar (glucose) The sugars can be used or can be converted to cellulose, starch, or other substances CHEMOSYNTHESIS So…why are producers important? Ecology is all about energy flow LIFE is all about energy flow Our source of energy is… Producers are… Consumers = heterotrophs Get their energy from the carbon bonds made by producers… 4 types: Consumer Trophic level Food source(s) Herbivores Primary Plants Carnivores Secondary or higher Animals Omnivores All levels Plants, animals, and others Detritivores ------------------ detritus Consumers Some animals do not specialize in their diets (called generalists)… they feed on several trophic levels. Consumers Most species are much more specific in their diets—these are called specialists. Which one are we??? Energy flow sun HEAT HEAT producers consumers Inorganic nutrients decomposers HEAT Energy flow Energy flows in the form of carboncarbon bonds (in organic molecules) Bonds = energy 1 glucose molecule = 686 kcal 1 ATP = 7.3 kcal 1 glucose 36 ATP So…38% of energy from glucose yields ATPs—62% lost as heat Energy flow Photosynthesis = C-C bonds formed (glucose) from sunlight (energy), water and CO2 Respiration = C-C bonds broken to form CO2 & energy ATP (used) heat (lost) All energy is, ultimately, lost—10% rule Food Chain Series of steps in an ecosystem in which organisms transfer energy by eating and by being eaten. Energy flows in one direction from sun or inorganic compounds to autotrophs to various heterotrophs Food Chain Arrows show the direction the energy is flowing. Food Webs Many food chains combined together. Hognose Snake Rabbit Toad Hawk Mouse Spider Grasshopper Grasses Garter Snake Preying Mantis Sparrow This is a grazing food web. Producers are at the base of this type of food web. www.stephsnature.com Food webs Food Webs A detrital food web. Detritus is the dead stuff that falls to the ground or substrate and feeds myriad critters. Decomposers are at the base of this type of food web. http://www.econguru.com/fundamentals_of_ecology/ecosystems.html Food Webs So…what’s wrong with food webs??? Focus on static structure Reliance on stability or persistence of species Poor model for analyzing more dynamic situations Do not fully account for all species and links present Ignore spatial and temporal variability Spatial variability Differences in the food web depending upon location in the ecosystem Vertically Horizontally (2D) Temporal variability Differences in the food web depending upon time Time of day Time of year crepuscular diurnal nocturnal Temperate Tropical Migrations Life cycles/stages summer winter wet dry Life cycles Young and adults have different diets Tadpole vs frog Caterpillar vs. butterfly/moth Grub vs beetle Mosquito larvae vs. adults Etc. Prevents competition for same resources ecosystems Rivet analogy Redundancy in the system Niche Microhabitats There are about 1.5 million rivets in a Boeing 737…how many would you remove (if you were flying in it)??? ecosystems • Common metaphor • • • • Stone arch Loading forces = interactions among species Keystone speciesholds it all up =stability (static) ecosystems •Dynamic in space and time • Members of the system (species/populations) •Adapt •Change strategies •Like a sports team ecosystems A better metaphor is Jenga (Jenga hypothesis) Governed by simple rules of balance & energetics Constantly changing—additions & deletions of parts Stability at any moment depends on the importance of a given ingoing or outgoing piece’s contribution to the structure Open and flexible Change species attributes, composition, and dynamics Ecological Pyramid Ecological Pyramid http://www.metrolic.com/travel-guides-the-great-pyramid-of-giza-147358/ Ecological Pyramid Uhhhh…wrong pyramid… Ecological Pyramid That’s more like it!!! Ecological Pyramid Is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. 3 types: biomass, energy, or numbers What is a trophic level? Ecological (biotic) pyramids As written by Aldo Leopold, “The species of a layer are alike not in where they came from, or in what they look like, but rather in what they eat.” Trophic levels First level = Second level = Third level = Fourth level = Biomass Pyramid The total mass of living tissue at each trophic level. Represents the amount of potential food available for each trophic level in an ecosystem Biomass Pyramid The first level includes producers. Here we find the most abundant amount of biomass. Biomass Pyramid Generally, the further removed a trophic level is from its source (detritus or producer), the less biomass it will contain. WHY? Not everything in the lower levels gets eaten Not everything that is eaten is digested Energy is always being lost as heat Biomass Pyramid A few exceptions… Aquatic ecosystems Algae outnumbered & outweighed by critters that eat them How does it work, then?????????? Algae can reproduce at least as quickly as they are eaten Algae are mostly digestible (much more so than terrestrial plants) Energy Pyramid About 10% of the total energy is transferred to this level to be used by these consumers. This is the 10% Rule 10 cal 100 cal 1000 cal 10,000 calories Ecological pyramids Numbers pyramid Pyramid of numbers The number of organisms at each trophic level. Biogeochemical Cycles Elements, Chemical compounds and other forms of matter are passed from one organism to another and from one part of the biosphere to another. Pass the same molecules around again and again within the biosphere. Matter is always recycled! Water Cycle Carbon cycle Nitrogen Cycle Phosphorus Cycle geology.usgs.gov Nutrient cycling Ecosystems can be sources, sinks, or transformers of chemicals Source = supplier of nutrients to other habitats Sink = “holder” of nutrients from other habitats Transformer = takes nutrients in one form and gives them up as another form NICHE All the roles that an organism plays in its environment. what it eats physical changes to habitat what eats it symbionts parasites what it takes from the habitat what it puts into the habitat Some Ecological Roles Prey Predator Symbiosis Commensalism Mutualism Parasitism + 0 + + + -