Asexual Reproduction
Sexual Reproduction recombination of genetic material More combinations means there is a higher chance at least some will survive a catastrophe Offspring not identical to parents
Sexual Reproduction Union 2 haploid (1n) gametes (Such as Sperm and Egg)to form a diploid (2n) Zygote
Diploid vs Haploid These terms refer to the number of sets of chromosomes an organism has. Humans are Diploid, we have two sets of chromosomes 46 total or 23 Pairs of “Homologous” chromosomes Sperm and eggs are haploid they only have 23 chromosomes each. When sperm and egg join the resulting zygote will have 46 chromosomes
Homologous Chromosomes Homologous means “Like” or “Same” Homologous chromosomes are chromosomes that code for the same genes. Remember that a gene codes for a protein that may result in a trait. The homologous chromosomes may have different version of the genes called “Alleles” They code for the same trait but may have different forms or colors.
Meiosis The process of making a haploid cell Also known as a reduction division because the number of chromosomes is reduced in this process. Two stages Meiosis I Meiosis II Results in 4 haploid (1N) Gamates
Meiosis I DNA is Replicated Homologous chromosomes line up in metaphase. This is when genetic recombination can occur… so not all offspring from the same pair will be identical! Very important for variation within a population and for the rise of new species. Results in 2 haploid cells
Meiosis I
Meiosis II DNA in NOT replicated in the two haploid cells chromatids separate and divide results in 4 haploid (1n) cells.
Meiosis II Meiosis II Telophase II Prophase II Metaphase II Meiosis II results in four haploid (N) daughter cells. Prophase II Metaphase II Anaphase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Prophase II Metaphase II Anaphase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell.