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Classification Early Systems Aristotle’s classification • Plant/animal? – Water/air dweller? Common name confusion : robin, fir tree, jellyfish Linneaus 1700’s Hierarchy based on morphology 7 original levels Domain (newest level) • Kingdom – Phylum (animal) Division (plant) • Class – Order – – – Family Genus species Classification Hierarchy of Organisms Binomial Nomenclature Species names has 2 parts: genus and species = scientific name Genus is capitalized species is not Italicize or underline Name may be descriptive or “in honor of” Systematics Taxonomy: naming and grouping of organisms Systematics – based on natural relationships including • Embryology, • Chromosomes • DNA/RNA Gets “revised” as new info is learned Cladistics Based on certain features “shared derived characters” I.e. feathers within birds (unique) Birds probably had a common ancestor because they all have feathers Phylogenetic Diagram of major groups of organisms 3 Domain System Based on analyses of rRNA Bacteria – (Eubacteria) Archae – (Archaebacteria) Eukarya (protists, fungi, plants animals) Modern Classification Modern Classification 6 Kingdoms w/in 3 domains • Archaebacteria • Eubacteria • Protista • Fungi • Plantae • Animalia ECOLOGY- Ch 18 Notes ECOLOGY • • • The study of living organisms and their interaction with the environment Interdependence: Everything is connected!!!! Make Models to help understand/explain Making an Ecosystem Model Levels of Organization • Biosphere - Earth & its atmosphere that supports life • Ecosystem - organisms & their environment (living & non-living in an area) • Community - interacting organisms, all living orgs. • Population - members of same species in one place • Organism - adaptations of individuals Levels of Organization Ecology Consists Of: • BIOTIC Factors - living things • ABIOTIC Factors - non living (pH, temp. sunlight, soil type) Responses to Environmental Change • • Acclimation - occurs within an individuals lifetime, you are able to function normally Control Internal Condition • Conformer - body temp rises & falls w/ environment (ex. Fish) • Regulator - use energy to control your insides (mammals) • Responses to Environmental Change Escape • hide underground if hot • dormant for long periods of time • migrate - move to better climate Tolerance Curve • • Level of change an organism can handle Range of an organism may be determined by this Niche’s • The role of the species in the environment • Fundamental - potential range of conditions & resources the species can tolerate • Realized - range of conditions & resources the species actually uses. Usually narrower than fundamental Earthworm Niche • • Niche Differences Generalists - Broad range of conditions & variety of resources (cockroach) Specialists - very narrow niche, feeds on specific food (koala) Energy Transfer • Involves • Producer • Consumer • Energy Flow Producers • • • Autotrophs - include plants, some protists & bacteria Photosynthetic - use sunlight as energy source Chemosynthetic - use inorganic molecules as energy source (hydrogen sulfide) Consumers • • • • • Cannot make their own food, must eat others, heterotrophs Herbivore: producer eater Carnivore: consumer eater Omnivore: eat producer & consumer Detritivore: Feed on “garbage,” dead stuff, animal waste – has a face • Decomposer - cause decay by breaking down tissue & waste – no face Who Eats Whom? • Food Chains (simple) • Food Webs (complex) • Trophic Levels: Energy flows from one trophic level to another Antarctic Food Chain Antarctic Food Web • • Trophic Levels Autotrophs: plants = 1st trophic level Heterotrophs: Cannot make their own food • Herbivores: 2nd trophic level • Carnivores: 3rd trophic level & up • Omnivores: Above 1st Trophic level What Happens as Energy Moves Through a Food Chain? • Organisms are not 100% efficient – about 10% of the energy at one level makes it to the next level (90% lost) The 10% Rule & Trophic Levels What Happens as Energy Moves Through a Food Chain? • Energy is lost, by the organisms basic needs and heat What Happens as Energy Moves Through a Food Chain? Implications • • Usually no more than 3-4 levels in a food chain Fewer and fewer organisms in the food chain as you go up Why are there more grasshoppers than grizzly bears? Productivity • • • How “productive” in making carbohydrates in the ecosystem Carbs used for - cellular respiration, maintenance, growth, reproduction biomass - amount of organic material produced in an ecosystem---producers add biomass Primary Productivity • • Gross Pri. Prod. (GPP) - rate producers capture energy….is total amount Net Pri. Prod. (NPP) - rate biomass accumulates (carbohydrates used for maintenance don’t result in biomass)….is amount left over after deductions made Net Primary Productivity • • • • Only biomass is available to other organisms 2 expressed as (kcal/m /yr) or g/m2/yr) NPP = GPP - respiration rate in producers Varies among ecosystems…. is biomass greater in tropical rain forest or desert? Biogeochemical cycles •Nutrients are essential to the success of ecosystems •Nutrients cycle between the biotic and abiotic components of the ecosystem •Removal of trees = higher rate of nutrient and water loss •CHNOPS are most important! Water Cycle= Hydrologic •More water = more diversity •Plants are integral - take up water, and it evaporates into atmosphere through their leaves (transpiration) •Evaporation from oceans & lakes •Involves precipitation, reservoirs of groundwater, vapor •No plants = lose water to runoff Water Cycle Carbon Cycle •Carbon is in carbon dioxide in air gets there by cellular respiration and burning fossil fuels •Taken out of air by photosynthesis •Living organisms are made of C, must get it by eating organisms •Cutting forests = increase CO2 levels - global warming Carbon Cycle Nitrogen Cycle •Needed for proteins and nucleic acids •Nitrogen gas makes up ~78% of atmosphere but cannot be taken in directly from air by animals; need to be assimilated by plants first Nitrogen Cycle 5 Steps to memorize Nitrogen fixation: take N2 gas out of air and convert into ammonia or nitrates (by bacteria & lightning) Nitrification: ammonium (NH4+) nitrate (NO3) by bacteria to be taken up by plants (soil bacteria oxidize) Assimilation: plants take up ammonia, ammonium and nitrate ions through roots (animals can then eat) Ammonification: dead organisms & waste (through urine/dung) contain Nitrogen ammonia & ammonium ions (by decomposer bacteria) for plants Denitrification: N2 released back into atmosphere (by bacteria) Plants use nitrates to form AA, animals get nitrogen by eating plants Nitrogen Cycle Phosphorus Cycle •phosphorus moves from phosphate deposited in rock, to the soil, to living organisms, and finally to the ocean Populations-Ch 19 Properties of Populations • Size - can be counted or estimated • Density - How crowded they are U.S. = 30 people/Km2 • Topics: • Dispersion • Growth rate • Age structure • Survivorship curves Dispersion • Clumped • Random • Uniform/Even Age Structure • % of individuals among different ages Patterns of Mortality • Shown in survivorship curves • Type I - young survive • Type II - many die young • Type III - most die young Measuring Populations • Demographers: study population dynamics • Growth Rate: Amount a population changes in a given time • Birth, death, immigration, emigration determine growth rate • Growth rate = B.R. - D.R. Calculating Populations • Done per capita (person) • Growth rate X current popl. Size = yearly increase • + = growing, - = decreasing Exponential Growth • Rapid increase after a few generations, the bigger it gets, the faster it increases • “J shaped curve” • B & D rate are constant • Populations cannot grow indefinitely like this because of limiting resources Two Growth Models Logistic Growth • Similar to exponential, but includes carrying capacity (max number = K) • Birth rate falls & death rate climbs as popl. grows • Carrying capacity can fluctuate • S-shaped curve Population Regulation • Density-independent: flood, fire, weather doesn’t matter how many individuals there are • Density-dependent: resource limitation, food, nesting site, brought on by increased population Population Fluctuation • More prey = more predators • Less prey = less predators • Wolf and moose population might cycle together Small Populations • Inbreeding is likely • Fewer offspring, more susceptible to disease, shorter life span, decreased genetic variability = bottleneck effect! The human popl. explosion • Long ago were hunter-gatherer’s, small populations, high mortality • Agricultural Revolution (10,000 years ago): Better food supply • Decrease death rate: sanitation, food, economics Demographic Transition • How populations change as a country industrializes The human popl. explosion History of Human Popl. Growth • Began ~1650 • After WWII fastest growth rate ever b/c of sanitation & medical care • Today: faster in developing rather than developed countries Developed Countries • 20 % of world popl. • U.S., Japan, Germany, France, Russia, Canada, Australia • Better educated, healthier, longer living • Growth rate is less than 0.01 Developing Countries • 80 % of world popl. • Most of Asia, Central America, South America, Africa • Poorer, less educated • Growth rate is more than 0.02