Contemporary Issues in Biology Final ~ TCU, Sawey Exam Questions and Answers

Contemporary Issues in Biology Final ~ TCU, Sawey Exam Questions and Answers how long have homo-sapiens been on earth - Answer- thought to be 200,000 years, starting in ethiopia mutation - Answer- change in nucleotide in the base of DNA; not all harmful; passed down in generations of that descent when did humans establish themselves worldwide - Answer- 12,000 years ago; before humans and agriculture coincided how did humans live before agriculture - Answer- used tools (needles, spears, clothes) and lived in small groups spread out of large areas of land when were large cities and civilizations possible - Answer- after we domesticated wild plants and animals and developed agriculture systems domesticated plant or animal - Answer- modified from its wild ancestors for its use by humans early domestication was unintentional - Answer- seeds brought back by hunter gatherers foraging in the wild grew by accident in large latrines and garbage dumps later domestication was conscious - Answer- scientists planted many different seeds, selected the best progeny and planted their seeds domestic crops - Answer- selected for maximum productivity and had little natural pest resistance pest attack problems - Answer- due to not selecting pest resistance during domestication DDT - Answer- invented as a pesticide but then pests became resistant (natural selection) --> selection pressure towards pesticides, invented in the 1940s biomagnification - Answer- concentration of pesticides in higher levels of food chains bald eagle problems over time - Answer- -egg shells thin and broke easily -number of young produced by each pair reduced -became endangered -banned ddt and then # of bald eagles increased world's leading producer of genetically modified crops - Answer- USA GMO - Answer- -genetically modified organism -genes are inserted that change the characteristics of the plant or animal -sometimes gene come from another organism... this is transgenic controversy over GMO's - Answer- -in regard to transgenic GMO's because this can introduce toxins into food crops -consequences of "tinkering with nature" current food crisis - Answer- -by 2050, additional 2 billion people in world -increase food production by 40% to meet need -GMO's easiest way for this to happen -GMO have crops have contributed to a 45% reduction in insecticide use continental drift - Answer- plate tectonics coevultion - Answer- -over 65 million years ago -species in food webs have evolved together so they depend on the presence of each other -mimicry (example)