ENVS 210 1st Edition Lecture 4Outline of Last Lecture II. Nuclear energya. Nuclear fissionIII. Isotopes and ionsa. Defining isotopesb. Defining mass numberIV. Radioactive isotopesa. Half lifeV. Radioactive elements released from FukushimaVI. Geologya. Earth’s layersb. Continental drift (Alfred Wagner and Pangaea)c. How plates moved. Plate interactions (convergent, divergent transform boundaries)e. Rock cycle (igneous, sedimentary, metamorphic rocks)f. Geologic hazards (earthquakes, volcanoes, tsunamis)Outline of Current Lecture VII. Ecological organizationa. Biosphereb. Ecosystemc. Communityd. Populatione. OrganismVIII. Tropic levelsa. Producersb. Consumersc. Detrivores and decomposersIX. Food webs and energy flowa. Food webb. Food chainX. Keystone speciesa. Removal of sea ottersb. Removal of Yellowstone wolvesCurrent Lecture- Ecological communitiesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Biosphere= sum total of living things on eartho Ecosystem= consists of a communityo Community= assemblage of populations of organisms living in the same place at the same place at the same time Members interact with each other Interactions determine the structure, function, and species composition of the communityo Population= group of individuals of a species that live in a particular areao Organism= individual living thing- Energy passes through tropic levelso Tropic levels= rank in the feeding hierarchy Producers (autotrophs) Consumers Detrivores and decomposerso Producers primary consumers secondary consumers tertiary consumers- Food webs show relationships and energy flowo Food chain= series of feeding relationshipso Food web= visual map of feeding relationships and energy flow Includes many different organisms at various tropic levels Greatly simplified; leaves out most species- Community dynamics are complex: some organisms play big roleso Keystone species= has a strong wide-reaching impacto Removal of keystone species has a substantial ripple effect (alters the food chain)o Removal of sea otters= control sea urchin population. W/o sea otters, sea urchin population would explode, kelp forests would die due to urchin’s overgrazing. Kelp forests offer great protection to species and homes, carbon storage, and protection fromcyclones and storms.- Wolves= keystone species in Yellowstone national parko Trophic cascade= predators at high trophic levels indirectly affect populations at low trophic levels (and many other things too) By keeping species at intermediate trophic levels in check Ex: extermination of the wolves at Yellowstone led to increased elk populations, which overgrazed vegetation and caused increase water runoff into surface waters and streams. Trees where then unable to reproduce or grow
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