Daniel Cassidy
Debate Speech Outline
Nature vs. Nurture
Introduction
Picture two sets of twins that you know; one is identical, one is fraternal. The first two are exactly the same. They’re intelligent, sociable, and it’s near impossible to tell them apart. The fraternal pair is markedly different. Though raised in the same household, one is very outgoing whereas the other is shy and very introverted. The environment is the same, so it must be a hereditary difference.
Purpose Statement
Nature is the dominant factor in human development
1. Split twin studies
2. Nature loads the gun
3. Orchids and Dandelions
Body
1. Split twin studies
a. Twins are split up at birth in order to study how their lives row to be different
b. Both identical and fraternal twins are split
c. Identical twins (same genes) are more susceptible to mental illnesses if they’re sibling has one compared to fraternal twins.
d. “For twin pairs where schizophrenia occurs, in 50% of cases both identical twins in a pair develop the disease, while only 10-15% of cases in fraternal twins show this pattern. This is evidence for a strong genetic component in susceptibility to schizophrenia.” From the University of Utah
2. Nature loads the gun
a. You can’t make something from nothing
b. Having certain genes in your genetic makeup can make you predisposed to be more susceptible to many different conditions such as obesity, cancer, and addictions.
c. “Women who were abused as children are known to have high rates of alcoholism and yet some show remarkable resilience despite a history of abuse. The difference in vulnerability can often be traced to variant versions of a gene that controls a key brain enzyme, MAOA (monoamine oxidase A), which helps regulate the brain's response to stress.” From Opposing Viewpoints
3. Orchids and Dandelions
a. We are constantly learning about new genes
b. “Scientists point to a type they call orchids—people who wilt under poor conditions but flourish in supportive climes. Meanwhile, dandelions aren't much affected by the world around them, whether supportive or harsh.” From University of Arizona by way of the Wall Street Journal.
c. This is because of variation in a gene called Dopamine Receptor D4 or DRD4. This gene regulates the amount of dopamine