| Unit 1: Environmental Science History of the environmental movement: - Expansionist Worldview- the industrial revolution brought urbanization and accelerated resource use and pollution. people believed that technology would be able to control nature - Ecological Worldview - humans live in harmony with nature. beliefs similar to those of the Aboriginal people Since Rachel Carson's book "The Silent Spring" there have been two waves of environmentalism: - 1st focused on local issues - 2nd focused on global issues Classifying Organisms: - Aristotle 2400 yrs ago first identified two kingdoms (plants and animals) - the invention of the microscope in 1664 opened up a new world - the microorganisms - Linnaeus in the early 1700's identified plants based on structure - assigned organisms 2 names (binomial nomenclature) - Taxonomy is the science of naming and assigning organisms to taxa: Kingdom--Phylum--Class--Order--Family--Genus--Species - Dichotomous keys are "yes-no" questions used to identify organisms - Cladogram is the branching diagram that shows the evolutionary history (phylogeny) of an organism. Cladograms are constructed by looking at homologous characters. - All organisms that appear after a branch will contain the character associated with the particular branch. - Analogous characters evolved independantly from one another by convergent evolution Biodiversity The 6 kingdoms are: Archaebacteria ancient bacteria; live in harsh environment; 1st life forms Eubacteria broad habitat range; important in decomposition Protista most are single celled eukaryotes; algae important producers Fungi cell wall not cellulose; important decomposers Plantae multicellular; photosynthesis; cell walls with cellulose Animalia don't produce own food; invertebrates and vertebrates - 3 levels of biodiversity include: genetic, species and ecosystem Ecosystems - are the communities of plants and animals within a particular environment which are linked by the flow of materials through the abiotic and the biotic sections. Therefore ecosystems vary in size and have no clear boundaries. Primary succession development of communities in a previous barren habitat with no soil; or on a bare rock surface that has been scraped clean (glacier, volcanc eruption...) Secondary succession begins where there has been vegetation and soil growth (burned forest) Energy Flow - Begins with the conversion of sun's energy to chemical energy by the photosynthetic organisms or PRODUCERS. All other organisms are CONSUMERS. - producer--->primary consumer--->secondary consumer--->tertiary consumer - Decomposers break down the organic waste and dead organisms - Detritivore - Energy Pyramid - the amount of energy that is transferred along a food chain decreases considerably from trophic level to trophic level. Only about 10% is converted to new biomass, as the other 90% is used as energy for respiration and other body functions. - Biomagnification - toxins accumulate at higher trophic levels: How? Nutrient Cycles: Know how humanas affect the cycles - Hydrologic Cycle - Carbon Cycle - Nitrogen Cycle - Phosphorus Cycle Types of Species - Endemic Species - native to the area - Exotic Species - introduced from another ecosystem; Identify 3 different species and there impact (termites, water hyacinth, Myconia) - Indicator Species - early warning signs of environmental damage - Keystone Species - play a crucial role in ecosystem functioning Species Interactions - Predation - feed on young and weak; important in population control - Symbiosis - two or more species living together ------Parasitism - one benefits and one harmed ------Mutualism - both benefit ------Commensalism - one benefits one is not harmed nor benefits - Competition - two or more species compete for the same resources - Fundamental Niche - the entire range of conditions an organism is potentially able to occupy - Realized Niche - actual range of conditions that a species occupies Population Growth - limited resources limit the size of populations - demography is the study of populations - 3 Features of Populations ------Population size ------Population density ------Dispersion (random, even and clumped) - J-curve represents exponential growth; however growth of populations is often limited by predators, disease and the availability of resources, therefore growth eventually slows and population may stabilize. S-curve - Carrying capacity - the maximum size of a population that the environment can sustain - Calculate population sizes given values for r, N, and K. - N=rN(K-N)/K - Density-dependant factors - resources such as foos, water, space - Density independant factors - temperature... - r-strategists are rapidly growing populations - K-strategists are slowly growing populations Estimating Population Size - Mark and Recapture Sampling ------total marked (M) = number of recaptures (m) total population (N) size of second ample (n) - Quadrat Sampling Human Impact |