Ecological Principles(2)-1

Ecological Principles(2)-1 - ENVHLTH 102/HLTHST 102 GLOBAL...

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Unformatted text preview: ENVHLTH 102/HLTHST 102 GLOBAL ENVIRONMENTAL HEALTH Ecological Principles Ecological Principles Biosphere Biosphere Deepest Ocean Trenches Highest Mountain Top (36,000’ below sea level) (30,000 above sea level) More Realistically Limit of Light Penetration Permanent Snow Line (600’ below sea level) (20,000 above sea level) 1 Ecological Principles Biodiversity Biodiversity 10 10 million different species of plant, animal, and microbial life on earth Humans Humans are unquestionably the most influential form of life on earth Why Why is biodiversity important? important? Evolution Evolution Species Species evolve in response to environmental pressures and, in turn, modify their physical surroundings Ecological Principles Atmospheric Atmospheric evolution leading to higher life forms 3.5 3.5 million years ago Early Early organisms (bacteria-like) emerge from water (bacteriaFind Find the atmosphere devoid of O2, but rich in CO2 CO CO2 provides a source of carbon for the evolution of more advanced photosynthetic organisms Use Use the sun’s energy to convert CO2 and H2O into carbohydrates, releasing O2 as a byproduct Primitive Organisms + H2O + CO2 Photosynthetic Organisms + CO2 + H2O + Sun Carbon-based food source Carbohydrates + O2 2 Ecological Principles Ecosystem Ecosystem Basic Basic functional unit reflecting how living (biotic) organisms interact with each other to process and cycle nutrients from non-living (abiotic) components of their nonenvironment The The concept of ecosystem is imprecise! Few Few ecosystems have definite spatial boundaries or exist in complete isolation, for example: “Pond ecosystems” are affected by entering materials from adjacent “terrestrial ecosystems” Birds Birds and insects move in and out of adjacent ecosystems Ecological Ecological Principles Biotic Biotic Community Organisms Organisms are not arbitrarily scattered around the earth, but dwell together in an orderly manner This This is referred to as a biotic community Recognize Recognize the importance of the biotic community as a whole, instead of its individual parts This This helps manage populations in the sense of increasing or decreasing numbers 3 Ecological Principles Disturbance Disturbance of a Stable Biotic Community The The Beaver Story (not Jerry Mathers) 1760s: Beaver Pelt Hats in Great Demand in Europe Europeans Pay High Prices for Pelts Ecological Principles Disturbance Disturbance of a Stable Biotic Community French Trappers Migrate to North America Late 17th Century 4 Ecological Principles The The Beaver Story Continued Extensive Trapping of Beavers Causes Near Extinction 150 years Early 1900’s Ecological Principles The The Beaver Story Continued Result of the Reduction in Beaver Population: Beaver Dams not Maintained and Wash Away 5 Ecological Principles The The Beaver Story Continued Result of Dam Destruction: Increased Stream Flows Note: Fish Need Quiet Waters for Breeding Corollary Result: Decline in Fish Populations Ecological Principles The The Beaver Story Continued Result of Beaver Dams Washing Away: Marshy Areas Either Drained or Flooded Dry Marsh Flooded Marsh 6 Ecological Principles The The Beaver Story Continued Result of the Change in Marsh Environment: Disruption of Waterfowl Nesting Sites Corollary Result: Decline in Bird Populations Ecological Principles The The Beaver Story Continued Another Result of Beaver Dams Washing Away: Increases in Frequency & Intensity of Stream Flooding Result: Corollary Result: Streamside Erosion and Stream Siltration Decline in other Biotic and Abiotic Species Needed for a Stable Ecosystem 7 Ecological Principles The The Beaver Story Summary Initial Observation: The beaver, is an economic resource going to waste in the vast wilderness of North America. Result: Exploitation of the beaver led to far-reaching farenvironmental consequences. British Periodical (October 2, 1795) The high-crowned beaver hat highis the newest fashion for gentlemen, gaining popularity over the longtime threethree-cornered tricorne hat. Ecological Principles TERRESTRIAL TERRESTRIAL BIOMES Ecologists Ecologists divide terrestrial communities into groupings called Biomes Biomes Recognized Recognized by the distinctive life forms of their dominant dominant species In In most cases, the key characteristic is the dominant dominant type of vegetation Each Each has its own temperature, seasons, and rainfall temperature, that support its characteristic vegetation Biomes Biomes are more or less latitude-driven latitude- 8 Ecological Principles Tundra Tundra (northernmost of the world’s land masses Characterized Characterized by permanently frozen soil: Low rainfall permanently (approx. 8 inches) In In summer, dotted with lakes and bogs dotted Permafrost Permafrost does not let moisture penetrate Windy, few Windy, few trees – dominant vegetation is moss, lichen, and moss, grass Animals Animals limited, but abundant in numbers – No reptiles or amphibians The The Tundra is fragile due to slow growth and slow decomposition rates Building Building on tundra can melt permafrost - uneven settling Ecological Principles Tundra 9 Ecological Principles Taiga Taiga (Russian word for swamp forest) Northern Northern Coniferous Zone – Covers much of Canada, Scandinavia, and Russia Dominant Dominant vegetation consists of conifer trees that have conifer needleneedle-like leaves Susceptible Susceptible to disease outbreaks Soils Soils are more acidic in nature acidic Precipitation Precipitation is moderate – swamps, ponds, and bogs are common in the northern most fringe of the biome Animals Animals – bears, moose, lynxes, wolverines, birds… Lack Lack of diversity of species creates “boom or bust” cycles “boom Ecological Principles Taiga 10 Ecological Principles Taiga Ecological Ecological Principles Temperate Temperate Deciduous Forest Most Most developed nations reside in this biome Rainfall Rainfall abundant relative to evaporation Wide Wide variety of animal and plant life Large Large annual leaf drop leads to soils rich in nutrients Exploitation Exploitation Lack Lack of remediation can destroy soil 11 Ecological Principles Temperate Deciduous Forest Temperate Deciduous Forest Ecological Principles Grasslands Grasslands (AKA Savannas) Low Low precipitation and high evaporation rates – cannot sustain tree growth Characterized Characterized by carnivores and herds of grazing animals carnivores This This biome has a higher concentration of organic matter in higher soil than other biomes – agriculture abounds in this biome Interlaced Interlaced system of roots and grass stems form a turf that prevents erosion Exploitation Exploitation Broken Broken turf (plowing or grazing) can subject the soil to the influences of wind and water 12 Ecological Principles Grasslands Ecological Principles Deserts Deserts Typically receive Typically receive 10” of rain per year or less Concentrated Concentrated in the latitudes 30° north and 30° south latitudes 30° 30° High High daytime and low nighttime temperatures Plants Plants have adapted to resist drought Waxy Waxy material on leaves and stems, reduced leaf size, and spiny growths to repel animals seeking moisture Sparse Sparse vegetation above ground – extensive root system below ground Desert animals Desert animals are typically nocturnal Soils Soils contain little organic matter – require water and nutrients to become productive 13 Ecological Principles Deserts Ecological Principles Tropical Tropical Rain Forest High High temps and high rainfall (100”/yr or more is common) Year Year round temp variation is slight temp Large Large variety of animals and plants Characterized Characterized by four layers of plant growth four Top Top canopy of trees (200’ AGL) Lower Lower canopy of trees (100’ AGL) A sparse understory sparse Few Few plants at ground level Soils Soils are thin and nutrient poor Leaching Leaching results in residues of iron and aluminum (laterite soils) 14 Ecological Principles Tropical Rain Forests Ecological Principles PRINCIPLE PRINCIPLE OF COMPETITIVE EXCLUSION When When two species compete for the same limited resources only one will survive Niche Niche diversification allows co-habitation of species coThe The Louse Story - body louse, head louse, and crab louse Cohabitation Cohabitation would mean demise of one of the species Niche Niche diversification has solved this problem Body Body Lice: feed from the neck down spending most of their time on clothing and acquiring a blood meal on body contact Head Head lice: feed on the head and neck cementing their eggs to the hairs of the scalp Crab Crab lice: morphologically suited for life among the widely spaced hairs in the pubic regions 15 Ecological Principles FOOD FOOD “ECOLOGICAL” CHAINS Energy Energy moving through an ecosystems Producers Producers: Green plants convert sun energy into food energy Consumers Consumers: Animals – herbivores, carnivores, omnivores Decomposers Decomposers: Bacteria and fungi recycle detritus material back into the soil for use by the producers Ecological Principles Ecological Ecological Pyramid Describes Describes energy relationships among members of the food chain Note Note that there is a 90% loss in energy acquired by consumers with each step up the pyramid 16 Ecological Principles Bioaccumulation and Biomagnification Bioaccumulation Bioaccumulation refers to how pollutants enter a food chain Biomagnification Biomagnification refers to the tendency of pollutants to concentrate as they move from one trophic level to the next 17 ...
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