Sexual Reproduction Nearly all eukaryotes undergo sexual reproduction. The variation introduced into the reproductive cells by meiosis appears to be one of the advantages of sexual reproduction that has made it so successful. Meiosis and fertilization alternate in sexual life…
Learning Objectives By the end of this section, you will be able to: Inherited disorders can arise when chromosomes behave abnormally during meiosis. Chromosome disorders can be divided into two categories: abnormalities in chromosome number and chromosome structural rearrangements. Because…
Learning Objectives By the end of this section, you will be able to: Sexual reproduction requires fertilization, a union of two cells from two individual organisms. If those two cells each contain one set of chromosomes, then the resulting cell contains…
Learning Objectives By the end of this section, you will be able to: Sexual reproduction was an early evolutionary innovation after the appearance of eukaryotic cells. The fact that most eukaryotes reproduce sexually is evidence of its evolutionary success. In…
Figure 7.1 Each of us, like these other large multicellular organisms, begins life as a fertilized egg. After trillions of cell divisions, each of us develops into a complex, multicellular organism. (credit a: modification of work by Frank Wouters; credit b: modification…
Mendel’s Experiments Working with garden pea plants, Mendel found that crosses between parents that differed for one trait produced F1 offspring that all expressed one parent’s traits. The traits that were visible in the F1 generation are referred to as dominant, and…
Learning Objectives By the end of this section, you will be able to: Mendel studied traits with only one mode of inheritance in pea plants. The inheritance of the traits he studied all followed the relatively simple pattern of dominant…
Learning Objectives By the end of this section, you will be able to: The seven characteristics that Mendel evaluated in his pea plants were each expressed as one of two versions, or traits. Mendel deduced from his results that each…
Learning Objectives By the end of this section, you will be able to: Figure 8.2 Johann Gregor Mendel set the framework for the study of genetics. Johann Gregor Mendel (1822–1884) (Figure 8.2) was a lifelong learner, teacher, scientist, and man of faith.…
Figure 8.1 Experimenting with thousands of garden peas, Mendel uncovered the fundamentals of genetics. (credit: modification of work by Jerry Kirkhart) Chapter Outline 8.1 Mendel’s Experiments 8.2 Laws of Inheritance 8.3 Extensions of the Laws of Inheritance Genetics is the study of heredity. Johann Gregor…