This chapter distinguish between the following terms: somatic cell and gamete, autosome and sex chromosomes, haploid and diploid; describe the events that characterize each phase of meiosis; describe three events that occur during meiosis I but not mitosis; name and explain the three events that contribute to genetic variation in sexually reproducing organisms. | Meiosis and Sexual Life Cycles Chapter 13 Overview: Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind Genetics is the scientific study of heredity and variation Heredity is the transmission of traits from one generation to the next Variation is demonstrated by the differences in appearance that offspring show from parents and siblings © 2011 Pearson Education, Inc. Concept : Offspring acquire genes from parents by inheriting chromosomes In a literal sense, children do not inherit particular physical traits from their parents It is genes that are actually inherited © 2011 Pearson Education, Inc. Inheritance of Genes Genes are the units of heredity, and are made up of segments of DNA Genes are passed to the next generation via reproductive cells called gametes (sperm and eggs) Each gene has a specific location called a locus on a certain chromosome Most DNA is packaged into chromosomes © 2011 Pearson Education, Inc. . | Meiosis and Sexual Life Cycles Chapter 13 Overview: Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind Genetics is the scientific study of heredity and variation Heredity is the transmission of traits from one generation to the next Variation is demonstrated by the differences in appearance that offspring show from parents and siblings © 2011 Pearson Education, Inc. Concept : Offspring acquire genes from parents by inheriting chromosomes In a literal sense, children do not inherit particular physical traits from their parents It is genes that are actually inherited © 2011 Pearson Education, Inc. Inheritance of Genes Genes are the units of heredity, and are made up of segments of DNA Genes are passed to the next generation via reproductive cells called gametes (sperm and eggs) Each gene has a specific location called a locus on a certain chromosome Most DNA is packaged into chromosomes © 2011 Pearson Education, Inc. Comparison of Asexual and Sexual Reproduction In asexual reproduction, a single individual passes genes to its offspring without the fusion of gametes A clone is a group of genetically identical individuals from the same parent In sexual reproduction, two parents give rise to offspring that have unique combinations of genes inherited from the two parents © 2011 Pearson Education, Inc. Concept : Fertilization and meiosis alternate in sexual life cycles A life cycle is the generation-to-generation sequence of stages in the reproductive history of an organism © 2011 Pearson Education, Inc. Sets of Chromosomes in Human Cells Human somatic cells (any cell other than a gamete) have 23 pairs of chromosomes A karyotype is an ordered display of the pairs of chromosomes from a cell The two chromosomes in each pair are called homologous chromosomes, or homologs Chromosomes in a homologous pair are the same length and shape and carry genes controlling the same inherited characters ©
