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Chapter 54

BIOLOGY 1M03 Chapter 54: Chapter 54

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Ben Evans

Chapter54–Ecosystems What is an ecosystem? • A biological community plus all the abiotic factors (climate, soil, energy, nutrients influencing that community) Insert fig. 54.1 the Four components of an ecosystem interact Insert fig 54.11 and 54.10 Four Components of Ecosystems 1. Abiotic Environment: • atmosphere, soil, climate, particulate matter and solutes in water 2. Primary Producers: (autotrophs) • utilize sunlight or chemical energy to synthesize their own food reduced organic substances from inorganic sources (via chloroplast / leaves) What mode of digestion do they use? o They are autotrophs (self-feeders)  photosynthesis Heterotrophs: get your own food (us) Chemotrophs: chemicals What is NPP? o Net Primary Productivity the energy invested into new tissue o Varies among geographic regions (different types of ecosystems) 3. Consumers • organisms that eat other organisms • ex. Primary, secondary, tertiary 4. Decomposers • acquire energy from consuming the dead remains of other organisms • with the help of bacteria or worms How have humans NEGATIVELY IMAPCTED ecosystems? • Oils spills (water pollution)  difficult to clean • Industries (air pollution and acid rain)  prevents active life • Poor logging practices (soil erosion)  clear cutting Who was RACHEL CARSON, why was her book “Silent Spring” so significant? • What would happen if we didn’t hear any of the birds chirping? • Brought public awareness to environmental issues o such as the negative impact of DDT pesticide • noticed bird shells were collapsing o when incubate egg it would break • she notes Biological Magnifications (see below) • told government officials and was able to get DDT banned in North America fig 54.2 tropic levels identify steps in energy transfer • food chain: • food webs: o shown bottom up, but can be top down o trophic levels identify steps in enegry transfer o should be able to identify the elemnets for final fig 54.4 the balsam fir food web • what real world food webs look like • number of species and number of species it interacts with • keystone has big impact on food web • computer programs can help with relationships fig 54.5 how do human consumers use primary production? • Maintenance activity: thermoregulation • Exertion can be used by other organisms Why do toxic compounds have the greatest effect on top-level carnivores? • Biological Magnifications BIOLOGICAL MAGNIFICATION fig 54.8 and one before • can lead to high concentration of toxic substances at trophic levels • toxins become progressively concentrated with each level of the food web • top-level carnivores are severely affected • ground water with DDT would go into lakes • PPM = parts per million • PPM in H2O were small, but organisms that lived in the water came in contact with DDT • DDT gets imbedded in the fatty tissue or adipose tissue of organisms o Once in, its in there forever • As the food chain continues, the concentration PPM increases o Higher organisms have to eat more of the lower, so concentration grows o Goes from 0.000003ppm to 25 ppm • zooplankton small fish large fish  fish eating birds DDT • innately thought it would only get rid of pests • spread over all crops and fields • causes egg shell thinning, threatening bird populations • DDT is now banned in North America • DDT is still being used in come countries and has been detected in the human breast milk o In humans it interferes with physical and neurological development growth of fetus • Hard for developing countries to find something better Ex. In lecture discussion: PREFRINE FALCONS (HAMILTON’S PROJECT) • All the birds have been marked and banded • By the B line buss near the Sheraton Hotel, the falcon like to lay their eggs • Hamilton Naturalist club  work to band children, make sure they are healthy, wash them etc. • Public awareness, Tourist attraction, great at finding mice etc. • When go and get eggs, the birds get very frustrated and attack head or poo on him In Lecture Discussion: THERE ARE STILL SOME COUNTRIES THAT USE DDT AS PESTICIDE. Should These Countries Be Made to Discontinue Their Use of DDT? Whose responsibility is it to change their mind? • High use DDT countries: El Salvador, Hong Kong, Guatemala, Mexico, Poland, Greece • Many of them have tried to use other substances instead of DDT • It was because people from North America would not buy their products • The countries that use it are probably not aware of the bio-ramifications fig 54. 13 generalized terrestrial nutrient cycle fig 54.24 per-capita oil consumption varies among countries • Different types of demands on the earth ex. Carrying capacity (finite) • Oil consumption varies o Cars and industries rely more on oil consumption • Habitat, oil spills, ecological disasters that have ramifications Are you willing to change your attitude towards “consumerism”? • The activities of mot North Americans indicate that we are “consumer and industrial” bent, therefore changing our attitudes may b
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