Chapter 11 Chromosome Number, Reproduction, & Genetic Variation

-Tutorial Thurs & Fri this week
-Midterm Progress Reports went out yesterday
-Including today, 4 more days of current unit
-Unit test & notebooks due Wed 5/25

Ch 11: Chromosome Number, Reproduction & Genetic Variation

Learning Objective: I can explain variations in chromosome number, the different types of reproduction, and the advantages of genetic variation.

Chromosome Number
Humans have 46 chromosomes in each somatic cell. Cells with two sets of chromosomes are called diploid (2n). Gametes are haploid cells and have only one set of chromosomes, so human gametes have 23 chromosomes (n=23).

*THINK:What are some different ways that organisms reproduce (make offspring)? 

Complete Reproduction worksheet (review vocab first)
Glue into notebook, do left side processing


Processing:T-chart with advantages and disadvantages of reproduction types

Examples of Asexual Reproduction:

Komodo Dragons can reproduce through parthenogenesis!
(2 min video)

Watch video clip of starfish regeneration (4 min)

Genetic Variation is an advantage for a population and can help a population survive a major environmental change. 
It is made possible by sexual reproduction in which genes are rearranged through meiosis. The fusion of haploid cells from two different individuals adds further variation. 
Contributions to genetic variation are:
1. crossing over (sister chromatids overlap and swap spots)
2. independent assortment (random distribution of chromosomes during meiosis)
3. random fertilization (possible gamete combinations & outcomes)

Chromosome numbers of common organisms

Sci Show 'Why Ferns Have More Chromosomes Than You'