70. Inbreeding and small population size of a threatened species can combine to form a downward spiral for the species known as a(n) _____.
(A) extinction vortex
(B) random change of allele frequencies attributable to chance
(C) random mutation
(D) accelerated evolution of new traits
(E) none of the possibilities are correct

66. Which statement is FALSE? (A) Succession is predictable. (B) Pioneer species have wide ranges of tolerances. (C) Pioneer plant species are usually small annuals with an abundance of easily dispersed seeds. (D) The succession that occurs in an abandoned field is primary succession. (E) Climax species are those that are best adapted to the specific climate where the succession occurs.

67. Which of the followings is a trend in the evolution of land plants? (A) Decrease in the size of the leaf (B) Reduction of the gametophyte phase of the life cycle (C) Elimination of sperm cells or sperm nuclei (D) Increasing reliance on water to bring sperm and egg together (E) Increasing spore size

68. Prokaryotic organisms have recently been divided into two domains, Bacteria and Archaea. This division is based on characteristics such as _____. (A) circular genome (B) no nucleus or membrane-bound organelles (C) presence or absence of histones (D) no introns (E) all of the above

69. Assuming complete dominance, crosses between two dihybrid F1 plants, which are offspring from a cross AABB x aabb, result in F2 phenotype ratios of _____. (A) 1:2:1 (B) 3:1 (C) 1:1:1:1 (D) 9:3:3:1 (E) 9:1

71. Which is NOT a recognized hypothesis to account for the strong competitive ability of invasives? (A) Enemy release (B) Superior competition (C) Lack of environmental constraints (D) Propagule pressure (E) Climate pre-adaptation

72. If a community exhibits lognormal rank abundance, we may conclude there are _____. (A) a large number of rare species, a large number of common species, and a few species of intermediate rank (B) a few rare species, a few common species, and a large number of species of intermediate rank (C) a few rare species and a large number of very common species (D) a few common species and a large number of rare species (E) rare species are very common

73. A new menstrual cycle begins with the production of _____, following the removal of inhibition by combination of _____. (A) GnRH, FSH and LH (B) GnRH, estradiol and progesterone (C) LH, estradiol and progesterone (D) estradiol, FSH and LH (E) estradiol, GnRH and LH

74. Which of the followings is NOT true of G protein-coupled receptors (GPCRs)? (A) GPCRs are cell-surface transmembrane receptors that work with the help of monomer G proteins. (B) GPCRs have similar structure in which a single polypeptide has seven transmembrane helices. (C) Epinephrine can target the same type of GPCR in liver cell and skeletal muscle blood vessel. (D) G protein systems are involved in cholera and pertussis diseases. (E) G protein functions as a molecular switch that is either on or off depending on GTP or GDP is attached.

75. Which of the following statements about genome is FALSE? (A) Usually, the gene density of archaea genome is higher than eukaryotes. (B) Usually, the number of genes of archaea genome is more than eukaryotes genome. (C) The genome size of archaea is less than eukaryotes. (D) The number of genes of fruit fly genome is less than Arabidopsis thaliana genome. (E) The number of genes of fruit fly genome is less than C. elegans genome.

76. Which of the following statements concerning human embryonic development is correct? (A) Inner cell mass is a group of cells that cluster at one end of the gastrula. (B) The trophoblast, the outer epithelium of the gastrula, supports embryo growth. (C) The trophoblast continues to expand into the endometrium, and four new extraembryonic membranes appear. (D) By the end of blastocyst, three embryonic germ layers have formed. (E) By the end of gastrulation, the extraembryonic ectoderm and extraembryonic membranes surround the embryo.