1. Characteristics of living things
REMEMBER THE…
Characteristics of living things
Living things are made up of cells
Unicellular – one celled organisms
Multicellular – many celled organisms

2. Characteristics of living things
Living things grow and develop

3. Characteristics of living things
Sexual reproduction
Two parents, offspring are not identical to parents
Living things reproduce to make offspring of the same species
Asexual reproduction
One parent, offspring are identical to parent

4. Body cells vs. gametes Body Cells: (hair, skin, blood)
Diploid (2N)
Produced through mitosis
Gametes: (sperm, egg)
Haploid (N)
Produced through meiosis
Diploid (2N) - have 2 sets of chromosomes
Haploid (N) - have 1 set of chromosomes

5. How many chromosomes are in a…?
Sperm Cell?
23 chromosomes
haploid (N)
Egg Cell?
White Blood Cell?
46 chromosomes
diploid (2N)

6. Homologous Chromosomes
Chromosomes that code for the same thing
One comes from the mom and one from the dad.
Paternal
Maternal
eye color locus
B = brown eyes
b = blue eyes

7. Meiosis
During Meiosis the Chromosome # is cut in half by separation of homologous chromosomes in diploid cells
4 haploid (N) sex cells (gametes) are produced
Genetically different from each other & the original cell

8. Meiosis
Cytokinesis 1
Cytokinesis 2

9. Differences between Mitosis & Meiosis
MITOSIS produces 2 identical diploid (2N) body cells
MEIOSIS produces 4 different haploid (N) gametes

10. Crossing Over
Before separating during meiosis, homologous chromosomes exchange genetic information
Creates genetic variation
library.thinkquest.org/ 19037/genome3.html

11. Segregation
When gametes are made during meiosis the alleles separate during a process called segregation.
Creates Genetic Variation.

12. Independent Assortment
Chromosomes separate without influincing eachother’s inheritance. (Blue eyes doesn’t always pair up with Freckles.)
Creates Genetic Variation B b
sperm
haploid (n)
meiosis II Bb
diploid (2n)
meiosis I Ff F f
This means all gametes will be different!

13. Sibling Variation
Independent Assortment insures that every sperm and egg that you make will be a little bit different which means you won’t look exactly like your siblings.

14. biology.clc.uc.edu/ courses/bio104/meiomito.htm