Question

22. Few or small mutations in throughout the history of life. may explain the occurrence of great phenotype changes a. developmental genes b. recessive alleles e dominant alleles de structural genes 23. Which is the most parsimonious and hence, most probable expl a. Multiple simultaneous beneficial mutations transton monious and, hence, most probable explanation for the evolution of flight in birds? resources previously not available to them. inicous beneficial mutations transformed front legs into wings, allowing them access to new b. Bird ancestors anticipated the need for wing anticipated the need for win the accumulated mutations needed for night c. Bird ancestors initially had mutations that made mutations that modified their front legs to become u ly had mutations that made their bones lighter in density to improve agility followed by new ed their front legs to become useful gliding structures. Finally, natural selection favored mutations that refined the elidine s e into wings that allowed them to tly. d. Bird wings were the result of consecu es were the result of consecutive neutral mutations which were not weeded out by natural selection Mellomrons th 24. Approximately how far back in time does the fossil record extend? a. 4 million years b. 6 million years o. 7 billion years d. 3.5 billion years 4. Before life originated, chemicals that were precursors for cells most likely underwent natural selection for a. large size. b. stable forms. c. reproductive success. d. complexity. 20. Which microorganisms transformed the earth's ancient atmosphere (which contained highly reducing gases such as ammonia, methane and hydrogen was) into an oxidizing atmosphere rich in oxygen gas? a. cyanobacteria b. archaea c. proteobacteria d. spirochetes

Answer 1

22)ans.d)-mutation in structural genes leads to change in phenotype.

24)ans.d)

25)ans.b)

26)ans.a)cyanobacteria or blue green algae ,photosythetic prokaryotes