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Across 1. egg cells and sperm cells 4. portion of the brain that sits on the brain stem; in general, it plays a role in complex adaptive processes (e.g., learning, perception, and motivation) 6. part of the brain on which the cerebral hemispheres rest; in general, it regulates reflex activities that are critical for survival (heart rate and respiration) 8. traits that are influenced by genes on the sex chromosomes 11. process by which the DNA molecule duplicates itself 13. study of functions and activities of the nervous system 14. possessing two identical genes for a particular trait 16. males establish this stable hierarchy through combative encounters with other males. Dominant males copulate more than nondominant males and thus are more effective in passing on their characteristics to future generations, which is why this type of dominance is important 22. class of chemical substances that includes adenine, thymine, guanine, and cytosine 27. evolution in unrelated species of similar solutions to the same environmental demands 28. accidental alterations in individual genes that arise during chromosome duplication 30. species that spend their larval phase in water and their adult phase on land 31. long chains of amino acids 35. double-stranded, coiled molecule of genetic material; a chromosome 36. study of nervous system disorders 37. thought to promote the evolution of new species so long as both in the pair react appropriately to the signals of the other 38. species whose young are fed from mammary glands 39. animals with dorsal nerve cords 42. trait of a dichotomous pair that is not expressed in the phenotype of heterozygous individuals 43. traits that an organism can pass on to its offspring through its genetic material 44. chordates that possess spinal bones 45. division of biopsychology that focuses on the use of functional brain imaging to study the neural bases of human cognition (complex mental processes such as thought, memory, attention, and perception) 46. study of the structure of the nervous system 47. idea that heritable traits that are associated with high rates of survival and reproduction are preferentially passed on to future generations 49. scientific study of behavior--of all overt activities of an organism as well as all the internal activities that are presumed to underlie them (e.g., learning, memory, motivation, perception, and emotion) 51. animal species grouping 52. breeding lines in which interbred membebers always produce offspring with the same trait, generation after generation 53. family of primates that includes Homo sapiens (humans), Homo erectus, and Australopithecus 54. one of 14 different orders of mammals: there are five families of them: prosimians, New-World monkeys, Old-World monkeys, apes, hominids 55. group of organisms that is reproductively isolated from other organisms; members of one species cannot produce fertile offpspring by mating with members of others species 56. scientific study of the nervous system 57. organism's observable traits 58. process of cell division that produces cells with the same number of chromosomes as the parent cell

Down 2. two genes that control the same trait 3. having a similar structure because of convergent evolution (a bird's wing and a bee's wing) 4. threadlike structures in the cell nucleus that contain the genes; each chromosome is a DNA molecule 5. process of cell division that produces cells (e.g., egg cells and sperm cells) with half the chromosomes of the parent cell 7. gibbons, organgutans, gorillas, and chimpanzees; evolved from Old-World monkeys; have long arms and grasping hind feet specialized for arboreal travel, have opposable thumbs that aren't long enough to be of much use for precise manipulation 9. traits that occur in one form or the other, never in combination 10. cell formed from the amalgamation of a sperm cell and an ovum 12. study of interactions between the nervous system and the endocrine system 15. having a similar structure because of a common evolutionary origin (e.g., a human's arm and a bird's wing) 17. members of the same species 18. trait of a dichotomous pair that is expressed in the phenotypes of heterozygous individuals 19. pair of chromosomes that determine an individual's sex: XX for female, XY for male 20. scientific study of the biology of behavior 21. According to Darwin, ability of an organism to survive and contribute its genes to the next generation 23. approach that focuses on the environmental pressures that likely led to the evolution of the characteristics (e.g., of brain and behavior) of current species 24. pertaining to illness or treatment 25. study of biological processes by comparing different species--usually from the evolutionary perspective 25. study of biological procseses by comparing different species--usually from the evolutionary perspective 26. cells that receive and transmit electrochemical signals 29. genes that contain the information required for the synthesis of a particular protein 32. study of the effects of drugs on neural activity 33. first vertebrates to lay shell-covered eggs and be covered by dry scales 34. study of the chemical bases of neural activity 40. possessing two different genes for a particular trait 41. center of the back 48. unit of inheritance; for e.g., the section of a chromosome that controls the synthesis of one protein 50. to undergo gradual orderly change