Bio 102 Unit 3 Week 3 Notes
Bio 102 Unit 3 Week 3 Notes Bio 102
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This 5 page Class Notes was uploaded by l_welden on Monday March 28, 2016. The Class Notes belongs to Bio 102 at University of Tennessee - Knoxville taught by Dr. Jeremy Chandler in Spring 2016. Since its upload, it has received 6 views. For similar materials see Introduction to Biology in Biology at University of Tennessee - Knoxville.
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Date Created: 03/28/16
Bio 102 Unit 3 Week 3 Notes XI. Chemical Cycling in Ecosystems A. General Info B. Biogeochemical Cycles a. Biotic Components b. Abiotic makes up an abiotic reservoir where a chemical accumulates or is stockpiled outside of living organisms c. Can be local or global d. 3 important chemicals: carbon, phosphorous, and nitrogen e. Viruses also impact these cycles 1. Carbon: -atmospheric reservoir -cycles globally -photosynthesis -cellular respiration 2. Phosphorous Cycle -nucleic acids -phospholipids -ATP -also required as a mineral component of vertebrae and teeth 2. Nitrogen Cycle a. Amino acids and nucleotides that make up DNA/RNA b. Nitrogen is an ingredient of proteins and nucleic acids c. Nitrogen Fixation---converts gaseous N2 to nitrogen compounds that plants can assimilate ` C. Virus a. Noncellular particle that must infect a host cell b. Not living because cannot reproduce on its own c. Infects: humans, plants, animals, other viruses d. Been around for a long time e. Bacteriophages: only attacks bacteria --- consists of a molecule of DNA, enclosed within a structure f. Lytic Cycle: A phage injects DNA into a cell and the cell eventually bursts, releasing the phage g. Lysogenic Cycle: Phage DNA is inserted into the bacterial chromosome and the phage is copied when the cell reproduces h. Viruses affect Biogeochemistry D. Nutrient Pollution a. The growth of algae and cyanobacteria ---algae blooms---harm aqueous ecosystems (can use up all of the oxygen in water) b. Nitrogen runoff form the Midwestern farm fields that drain into the Gulf of Mexico c. Eutrophication: enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus or both ---- can cause reduction in oxygen in water, algae blooms that secrete toxins, and algal “bust” after bloom leads to mass nutrient releases XII. Human Evolution A. Similarities in all humans a. We all share the same DNA blueprint and have similarities with chimps, mice, fruit flies, yeast, and plants b. We are all 99.9% similar to each other and are only .1% different c. Only a small percentage of our DNA makes us different from one another d. Molecular clock: the temporal information contained in a macromolecular sequence that are based on the acquisition of new random mutations in each round of DNA replication e. The virus HERV-K111 is on our genome on chromosome 9 because i. A retrovirus took its genetic information and integrated it into the host cell (maybe a sperm or egg cell repeatedly) and change genetic code---junk DNA affected ---evidence that many attributes in cells today can be attributed to viruses---(retro)viruses found in the placenta and may play a major role in pregnancy---in an experiment in which the viruses were taken out of a sheep, specialized cells in the placenta were not developed and the embryo could not implant into the uterus --- a retrovirus may be the reason for blue eggs in some chickens f. Facts i. Several species of humans lived at the same time j. Different human features evolved at different times g. Human Ancestry a. Primates: evolved from ---distinguished by characteristics shaped by the demands of living in trees, including limber shoulder joints, eyes in front of face, excellent eye-hand coordination, and extensive parental care ---three groups b. Humans and chimps shared a common ancestor (nor chimps) and represent two divergent branches from both ends of the tree c. Hominid: any member of the family Hominidae (humans, orangutans, chimps, gorilla, bonobos) d. Primary differences between humans and chimps: i. Bipedal---probably evolved first (Australopithecus walked around Savannah before Homo)---very old trait---maybe because of stability in the environment (evidence of change in microbial fossils) ii. Larger brain size B. History 1. Ardipithecus ramidus (4.4 M) i. Small brain ii. Walks upright iii. Also fours in trees 2. Australopithecus (2.6 M) i. Could walk upright ii. Lived on ground iii. Tools! 3. Homo Habilis i. Larger brain---increase in brain cavity size ii. Walked upright iii. Made stone tools 4. Homo erectus i. Controlled fire ii. One of the first species to extend humanity’s range outside of Africa--- dispersal began 1.8 M years ago iii. Taller than H. habilis iv. Larger brain 5. Homo neanderthalensis i. Regionally diverse descendants in Europe and Asia ii. Shared common ancestor with modern humans iii. Interbred with modern humans 6. Homo sapiens i. 200000 years ii. oldest DNA from 45000 years ago in Siberia iii. Longer childhoods due to brain development iv. Big brains C. More on Homo sapiens a. Oldest known fossils were discovered in Ethiopia and date from 160,000 to 195,000 years ago b. DNA strongly suggests that all living humans can trace their lineage to a single African lineage that began 160,000 to 200,000 years ago---“Out of Africa” hypothesis---humans originated in Africa and then migrated to other continents c. Genetic testing supports this theory----use of mtDNA (mitochondrial DNA---inherited from mothers) to track human ancestry and build and evolutionary tree (“Mitochondrial Eve – mtEve”)---humans evolved form one lineage, not one fixed individual d. Fossil Records show that humans emerged from Africa in one or more waves---oldest outside of Africa are 50,000 years old---New World is at least 15,000 years e. Humans developed societies because of several traits: i. Primate brain grows after birth and period of growth for humans is longer than any other primate ii. Extended period of human development lengthens the time for parents to care for their offspring and pass along culture D. Genetic Diversity in Humans a. Denisovians: i. Discovered bone fragments 2000 and 2008---mtDNA and nuclear DNA obtained to sequence ii. 3 recent lineages account for much genetic diversity iii. oldest Hominid DNA found is 400,000 b. Neanderthals i. Some populations had human DNA and some didn’t c. Homo sapiens i. Most people’s genomes contain remnants from African and the two above due to ancient interbreeding E. Impact of Homo sapiens on Earth i. Cultural evolution made modern humans a new force in history---most numerous and widespread of all large animals and bring environmental change faster than many species can adapt ii. How We evolve 1. Physical Body has not changed much 2. Different Environments let different populations have special features 3. Misconception: evolution took place a long time ago 4. Lactose tolerance: 95% northern European descendants can drink milk beyond traditional weaning period 5. Loosing wisdom teeth 6. Better immune systems 7. Brains are shrinking 8. Sickle hemoglobin in some populations as an adaptation to malaria---heterozygote advantage 9. Tibetans don’t need as much oxygen in high altitudes 10. Acclimazation: adaptive physiological or behavioral changes within an organism in response to their natural climate or environment 11. Skin color due to environment ancestors were in ---weaker the UV light, the lighter the skin (melanin to protect from this light) F. The Genetic Melting Pot a. 9 ancestral regions of modern humans 1. Northeast Asian 2. Mediterranean 3. Southern African 4. Native American 5. Oceanian 6. Southeast Asia 7. Northern Europe 8. Sub-Saharan African