Meiosis

Review:

Homologous chromosomes Gametes Gene Diploid (2n) Haploid (n) Somatic cells Autosomes Sex chromosomes Mitosis

Why is sexual reproduction more beneficial to a species than asexual reproduction – over time?

Asexual Reproduction

Sexual Reproduction leads to diversity!

How does meiosis result in diversity? Homologous chromosomes trade parts during

Prophase I – crossing over.

Homologous chromosomes get shuffled – Independent Assortment

You never know which of the homologous chromosomes will end up in which egg.

Where are gametes made in the human body?

Ovary

Meiosis – Reduction Division Watch this process and think about how

meiosis (the formation of gametes) is different from mitosis.

How is a zygote formed?

Meiosis: Males vs. Females

Males: Meiosis and sperm

production begins at puberty

Continuous process that males will always undergo – takes 9 weeks

Females: Meiosis and egg production

begins before birth. Process stops abruptly, and does not begin again until puberty

At puberty, one egg each month resumes meiosis and finishes its development

Process stops when a women reaches menopause (around 50 years of age)

Meiosis of a singe egg could take 50 years to complete!

Comparison of mitosis and meiosis

Skin Cells Egg Cells

Diploid

Haploid

Somatic Cells or Body Cells Gametes or sex cells

Meiosis Review

Diploid Vs. Haploid?

Gametes Vs. Somatic Cells

Can you explain this diagram?

Meiosis FoldableDraw and Label: Diploid cells Homologous chromosomes Crossing over Haploid cells

Explain: Are the newly formed haploid cells genetically identical to the parent cell? Explain why or why not.

Meiosis Review The Meiosis Square Dance Meiosis I Animation Meiosis II Animation