1. Parents can produce many types of offspring

Families will have resemblances, but no two are exactly alike

2. Every cell has a nucleus

Every nucleus has chromosomes

The number of chromosomes depends on the species

Ex.  Humans have 46

3. GENES are located on chromosomes

genes control the TRAITS of the individual

genotype determines phenotype


4. Chromosomes come in matching sets

-these are called homologous pairs

Cells in your body have a complete set (all 46) - they are called DIPLOID

Sex cells (sperm and eggs) only have half (23)  - they are called HAPLOID


find homolog


When GAMETES combine, the ZYGOTE (offspring) gets half from mom (23) and half from dad (23)

ZYGOTES are diploid  (46)

When sperm and egg meet, their chromosomes much match for the zygote to develop properly.


Let's Review Vocabulary.....

1.  Matching sets of chromosomes are called ________ pairs

2.  Egg and sperm combine to make a _______________

3.  Egg and sperm are both known as _______________

4.  A cell that only has half of a set of chromosomes is said to be _______________.

5.  Genes are located on  ___________________

The process of creating a gamete (sex cell) is called MEIOSIS

It is similar to mitosis, but  will produce 4 daughter cells that are each haploid.

Oogenesis  - makes eggs (ovum)
Spermatogenesis - makes sperm



- homologous pairs form
-chromosomes trade genes, 

 Crossing-over increases the number of possible gene combinations

Steps of Meiosis


Additional Resources

Label the Phases of Meiosis | Chromosome Study (Karyotype) | Meiosis Internet Lesson