1. Chapter 13
Meiosis

2. Outline I An Introduction to Heredity
A. Offspring require genes from parents by inheriting chromosomes
B. Like begets like, more or less; a comparison of sexual vs. sexual reproduction

3. Outline II. The Role of Meiosis in Sexual Life Cycles
A. Fertilization and meiosis alternate in sexual life cycles
B. Meiosis reduces chromosome number from diploid to haploid

4. Outline III. Origins of Genetic Variation
A. Sexual life cycles produce genetic variation among offspring
B. Evolutionary adaptation depends on a population’s genetic variation

5. Reproduction
Heredity: Continuity of biological traits from one GENEration to the next and involves the transmission of genes.
Variation: Inherited differences among individuals of the same species.
Genetics: The scientific study of hereditary and hereditary variation.

6. Heredity Possible due to the exact replication of DNA
Sperm and ova combine to from unique zygote
DNA: Deoxyribonucleic Acid; 4 bases A-T, G-C
Genes: Units of hereditary information that are made of DNA and found on chromosomes: specific sequence of DNA that codes for proteins which produces an organisms traits.

7. Chromosomes
Organizational unit of hereditary material in the nucleus of eukaryotic organisms
Consist of a single long DNA molecule that is highly folded and coiled along with histone proteins
Contain genetic material arranged in a linear sequence
Contain hundreds or thousands of genes each on a specific region of the DNA molecule called a locus

8. Meiosis

9. ComParing Sexual and asexual Repro
Single individual is the sole parent
Offspring are genetically identical to the parent
Results in a clone, with the possibility of mutation.
SEXUAL REPRO
Two parents give rise to offspring
Each parent gives half of its genes
Offspring have a unique combination of genes inherited from both parents
Variation. Lots of it.

10. Life Cycle of Humans Meiosis and fertilization
Life Cycle: sequence of all the stages in an organisms reproductive history from conception to production of its own offspring
Somatic Cell: body cell (not sperm or egg, 46ch)
Karyotype: A display or photomicrograph of an individual’s somatic cell metaphase chromosomes arranged in a standard sequence

11. Homologous Chromosomes
A pair of chromosomes that have the same size, centromere position, and staining pattern
All but sex cells have genes in the same loci
Autosome: non sex chromosome
Sex Chromosome: XX or XY
Remember Diploid, Haploid, Gamete, Fertilization, Gamete