Meiosis

1) Define terms evolution and natural selection 2) Define homologous chromosomes and identify chromatids 3) Differentiate between haploid cells and diploid cells 4) Describe the structure and function of the spindle 5) Summarize the steps of mitosis Review

Evolution is change in genetic makeup of a species overtime Evolution is change in genetic makeup of a species overtime. Natural selection is the process in which organisms with favorable genes are more likely to survive and reproduce. Homologous chromosomes are similar in shape, size and genes. Chromatids are copied chromosomes still attached at the centromere. Answers

3) Diploid cells have two sets of chromosomes 3) Diploid cells have two sets of chromosomes. Haploid cells have one chromosome set. 4) The Spindle is a structure made of microtubules. During mitosis, it helps to organize and separate chromosomes. Answers

5) Prophase-Chromosomes coil, spindle forms, nuclear membrane breaks down. Metaphase- Chromosomes line up on the cell equator. Anaphase- Chromatid pairs separate and move to opposite poles. Telophase- chromosomes unwind, nuclear membranes form. Answers

Take a few moments and read the first two pages in chapter 7 then answer these questions: 1) What is the topic of Section 1 2) How are meiosis I and meiosis II similar? 3) How are meiosis I and meiosis II different?

What is the topic of Section 1 ? Formation of haploid cell, how meiosis increases variation and gamete formation 2) How are meiosis I and meiosis II similar? Both go through similar Prophase, Metaphase, Anaphase and Telophase steps. 3) How are meiosis I and meiosis II different? Only Meiosis I do homologous chromosomes pair up and crossing over occurs. Answers

The purpose of this unit is to understand the process of meiosis and why its important that reproductive cells (gametes) have only half the number of chromosomes as other body cells (somatic cells). You will also learn how sexual reproduction in organisms results in genetic variation and how reproduction in some organisms involves only one parent. Purpose

Take a look at the figure on page 142 what do you see?

Organism Diploid Chromosome Number Fruit Fly 8 Garden Pea 14 Horse 64 Calculate the number of chromosomes in each organism through 5 generations, assuming the chromosome number doubles each generation Fruit Fly: 8-16-32-64-128; Garden pea: 14-28-56-112-224 horse: 64-128-256-512-1024

Meiosis and the joining of gametes are essential to evolution Meiosis and the joining of gametes are essential to evolution. No genetic process generates variation more quickly. Understanding probability will help you understand how incredible this process is and genetic variation. Probability