1. Heredity
S7L3. Students will recognize how biological traits are passed on to successive generations.
S7L3.a Explain the role of genes and chromosomes in the process of inheriting a specific trait.
S7L3.b Compare and contrast that organisms reproduce asexually and sexually (bacteria, protists, fungi, plants & animals).
S7L3.c Recognize that selective breeding can produce plants or animals with desired traits.

2. Important Vocabulary Genetics- the study of heredity
Heredity- Passing of traits from parent to offspring.
Trait- physical characteristic
Ex: brown hair, red hair

3. Offspring
Organism that is the result of reproduction

4. How do you inherit traits?
Meiosis
Occurs in gametes (sex cells): sperm in males & egg in females
results in 4 cells with ½ as many chromosomes
New cells are genetically different

6. Who was Gregor Mendel?

7. How Mendel's pea plants helped us understand genetics

8. Who was Gregor Mendel? Discovered the principles of heredity
Father of Genetics
Austrian monk
born in 1822
known for research and teaching
after his death (1884) acknowledgment of his discoveries in 1900
Discovered the principles of heredity
Performed experiments with pea plants
Realized that offspring
inherit traits from their
parents

9. What decides what traits get passed down?

10. Dominant trait Trait that masks or covers the other form of the trait
Represented with a capitol letter
Examples
Round seed –R
Tall plant--T
purple flower—F

11. Recessive trait Trait that is masked or covered by a dominant trait
Represented with a lower case letter
Examples
Wrinkled seed—r
Short plant—t
White flower--f

12. genes Your traits are determined by your genes.
Instructions for an inherited trait

13. Each parent gives
one set of genes to the
offspring
Offspring has 2 forms
of the same gene
for every characteristic

14. allele Tt Different forms of a gene are called alleles.
Can be dominant alleles or recessive alleles
Example Tt
Dominant allele recessive allele

15. Practice

16. Monster # 1 has Rr or 1 dominant and 1 recessive allele
How many eyes will this monster have???

17. Monster # 2 has RR or 2 dominant alleles
How many eyes will this monster have???

18. Monster #3 has rr or 2 recessive alleles
How many eyes will this monster have?

19. Baby Boom Genetics Activity
Choose 2 aliens that will mate to create an offspring
Flip the coin to choose the alleles that will combine to create traits
Use the “screen clipping” option in Microsoft word to create a 1 page document of the parents and their offspring
After your teacher has checked your document you may print.

20. Exceptions to the rules
Incomplete dominance- there is a blending of traits expressed; neither trait is fully expressed

21. Codominance- both alleles are shown

22. Genotype Combination of genes for a specific trait Example: TT, Tt, tt
** expressed
in letters

25. Phenotype Physical appearance of the trait
Examples: purple flowers, white flowers, yellow seeds, white seeds

26. Answer the following questions on the back of your Alien Offspring Print out
What is the difference between genotype and phenotype?
Give an example of when dominant allele masked a recessive allele in your offspring.
What recessive traits did your offspring inherit from their parents?

27. Punnett Squares
Tool used to organize all possible combinations of offspring from particular parents

29. Homozygous genotype Two same alleles for a trait aka—Purebred
Examples: TT, tt

30. Heterozygous genotype
2 different alleles for the same trait
aka hybrid
Example: Tt