Meiosis

• Meiosis makes gametes.
• The goal in biology is to make as much offspring possible.
• Pros for Sexual Reproduction: resistant to environmental factors, adapts to environment, more diversity, can be different genetically, provides foundation for evolution.
• Cons for Sexual Reproduction: slower, less offspring, needs a partner.
• Pros for Asexual Reproduction: faster, more offspring, does not need a partner.
• Cons for Asexual Reproduction: less survival, less diversity, vulnerable to environmental factors, all alike, species cannot change and adapt, and one disease can wipe out the entire population.
• Chromosomes are not chosen by sexual reproducers. They can get mutations, or they do not.
• 23 chromosomes come from the sperm and egg each. There is 46 together.
• Genetics: study of how traits are passed from parent to offspring.
• Chromosomes are made up of proteins and nucleic acids. The proteins keep it together and the nucleic acids are the DNA.
• Bacteria has 1 circular chromosome.
• Eukaryotes have more than 1 chromosome and are not circular.
• Chromosomes are packaged DNA.
• All living things reproduce.
• Bacteria reproduce via Binary Fission.
• Budding and regeneration are used by plants and animals in mitosis where identical copies of parent cells are made.
• Traits are determined by the genes on the chromosomes. A gene is a segment of DNA that determines a trait.
• Binary Fission and Mitosis produces cells that are identical.
• Sexual reproduction produces offspring that is genetically different from parents.
• 23 chromosomes in egg and 23 chromosomes in sperm add up to 46 chromosomes in the baby.
• Meiosis makes cells with half the number of chromosomes for sexual reproduction.
• Body means somatic.
• Cells that make up the body are somatic and diploid.
• Diploid: two copies of each chromosome. Always even.
• Haploid - one copy of each chromosome.
• Sperm and egg cells are haploid.
• All gametes are haploid.
• Gametes: sex cells
• Sexual reproduction only is a combination of gametes.
• 2n: diploid - mitosis: diploid to diploid.
• 1n: haploid - meiosis: diploid to haploid.
• Meiosis is an alteration to mitosis.
• Meiosis produces 4 different haploid cells, which are gametes.
• Meiosis is made through sexual reproduction.
• Meiosis goes through the stages twice.
• Independent Assortment: chromosomes line up in metaphase randomly.
• 7 pairs of chromosomes can line up in 2 different ways, 2^7 = 128 different sex cells possible.
• Lining up of homologous pairs are random.
• There are over 8.3 million different egg or sperm cells (2^23) and over 70 million different zygotes.
• Meiosis has genetic variation.