THE CREATION OF SPERM & EGGS (OVA) IN ANIMALS MEIOSIS THE CREATION OF SPERM & EGGS (OVA) IN ANIMALS

Humans have two sets of chromosomes so we note this as 2n Gametes have only 1 set of chromosomes so we note this as n

OOGENESIS- Creation of an egg

Animation

Meiosis has two Stages of Division Why? Because it creates 4 cells and each can only have _____chromosomes. Meiosis I Prophase I, Metaphase I, Anaphase I, Telophase I Meiosis II Prophase II, Metaphase II, Anaphase II, Telophase II

MEIOSIS I http://bcs. whfreeman. com/thelifewire/content/chp09/0902002

MEIOSIS II

Prophase I Crossing over of homologous chromosomes animation

Prophase I Crossing over of homologous chromosomes animation Sister chromatids

MITOSIS V. MEIOSIS http://www.biologyinmotion.com/cell_division/index.html

MITOSIS V. MEIOSIS CHART

Sexual v. Asexual Reproduction Asexual –creation of genetically identical offspring mostly simple, one cell organisms Only need one parent to produce offspring Shorter Development time, more offspring produced No genetic variety, pass on mutations easily Sexual –creation of genetically diverse offspring due to: 1. Crossing over 2. Independent Assortment of chromosomes 3. Random fertilization of gametes 4. Greater chance of favorable variations passed on

Nondisjunction Failure of homologous chromosomes to separately evenly during mitosis or meiosis http://www.sumanasinc.com/webcontent/animations/content/mistakesmeiosis/mistakesmeiosis.swf

Types of chromosome mutations https://highered.mheducation.com/sites/9834092339/student_view0/chapter15/changes_in_chromosome_structure.html