1. Heredity, Gene Regulation, and Development
I. Mendel's Contributions
II. Meiosis and the Chromosomal Theory
III. Allelic, Genic, and Environmental Interactions
IV. Sex Determination and Sex Linkage

2. Heredity, Gene Regulation, and Development I. Mendel's Contributions
II. Meiosis and the Chromosomal Theory
III. Allelic, Genic, and Environmental Interactions
IV. Sex Determination and Sex Linkage
A. Sex Determination
Environmental Sex Determination
a. Temperature
MT FT

3. Heredity, Gene Regulation, and Development I. Mendel's Contributions
II. Meiosis and the Chromosomal Theory
III. Allelic, Genic, and Environmental Interactions
IV. Sex Determination and Sex Linkage
A. Sex Determination
Environmental Sex Determination
a. Temperature
MT FT

4. “Jack-in-the-Pulpit”
A. Sex Determination
Environmental Sex Determination
a. Temperature
b. Size/Nutrition
Arisaema triphyllum
“Jack-in-the-Pulpit”
Small plants - male
Large plants - female

5. Sexually mature female
A. Sex Determination
Environmental Sex Determination
a. Temperature
b. Size/Nutrition
c. Social Environment
Sexually mature female
(Inhibits development of males)
Sexually mature male
Immature males
Wouldn’t the species do better if there were more females/group?
Yes, but selection favors individual reproductive success.

6. The presence of 1 or 2 sex chromosomes determines sex
A. Sex Determination
Environmental Sex Determination
Chromosomal Sex Determination
a. Protenor sex determination
The presence of 1 or 2 sex chromosomes determines sex
Order: Hemiptera “True Bugs”
Family Alydidae – Broad-headed bugs

7. The type of sex chromosomes determines sex
A. Sex Determination
Environmental Sex Determination
Chromosomal Sex Determination
a. Protenor sex determination
b. Lygaeus sex determination
The type of sex chromosomes determines sex
Order: Hemiptera
Family: Lygaeidae “Chinch/Seed Bugs”

8. Which sex is the ‘heterogametic’ sex varies
A. Sex Determination
Environmental Sex Determination
Chromosomal Sex Determination
a. Protenor sex determination
b. Lygaeus sex determination
Which sex is the ‘heterogametic’ sex varies
XX female, XY – male
Most mammals, including humans
Some insects
Some plants
ZZ male, ZW female
Birds
Some fish
Some reptiles
Some insects (Butterflies/Moths)
Some plants

9. Xg Y XG XGXg XGY XG Y Xg XGXg XgY Sex Determination Gender Sex Linkage
example: red-green coloblindness in humans
MALE
FEMALE Xg Y XG
XGXg
XGY
MALE
FEMALE XG Y Xg
XGXg
XgY
100% G, for all offspring 50% G daughters, 50% g sons
Now, the sex of the parent that expresses the G trait matters; the transmission of this gene correlates with the sex of the offspring, because this trait and ‘sex’ are influenced by the same chromosome.

10. Queen Victoria of England
Her daughter Alice
X-linked recessive traits are expressed in males more than females, because females get a second X that may carry the dominant allele.