Topic 3 : LH Trade offs Flashcards
What is a Genome-Wide Association Study (GWAS)?
A method used to scan genomes for genetic variations associated with a particular trait or disease.
Helps identify genetic factors influencing human traits and susceptibility to diseases.
What does the Out of Africa Model suggest about modern human origins?
It suggests that Homo sapiens evolved in Africa and then dispersed across the world.
Supported by genetic evidence showing that African populations have the highest genetic diversity.
Define Serial Sequential Migration.
Humans migrated out of Africa in successive waves rather than all at once.
Each migrating group carried only a subset of genetic diversity, leading to genetic bottlenecks.
What are microsatellites used for in genetic studies?
Short, repetitive DNA sequences useful for studying genetic variation and evolutionary history.
They help track lineage and migration patterns in human populations.
What is myotonic dystrophy linked to?
Founder effects, which occur when a small population is isolated, leading to reduced genetic variation.
Example: High prevalence in certain French-Canadian populations due to ancestral bottlenecks.
How does measles relate to demographic history?
Measles requires a large population (>250,000) to sustain transmission.
Historically, small populations would see outbreaks followed by the virus dying out.
What is an evolutionary mismatch?
When an organism’s traits, adapted for past environments, become maladaptive in a new environment.
Example: Human metabolism evolved for a hunter-gatherer lifestyle, but modern diets contribute to obesity.
Define geo-evolutionary mismatch.
A subset of evolutionary mismatch where humans live in environments vastly different from where their ancestors evolved.
Example: Migration from equatorial regions to high latitudes may lead to vitamin D deficiencies.
List types of evidence for geo-evolutionary mismatch.
- Epidemiological data linking disease prevalence to geographic ancestry
- Genetic adaptations (e.g., lactase persistence)
- Experimental studies showing physiological maladaptations
What are the two major epidemiological transitions?
- First transition: Shift from hunter-gatherer societies to agriculture
- Second transition: Shift from infectious to chronic diseases due to modern medical advancements.
What does the hygiene hypothesis suggest?
Lack of early childhood exposure to microbes increases susceptibility to allergies and autoimmune diseases.
Modern sanitation may contribute to rising asthma and allergy rates.
Define life history.
The probability of survival and rate of reproduction at each age in an organism’s lifespan.
Traits include birth size, growth rate, reproductive timing, number of offspring, and lifespan.
What are life history trade-offs?
Constraints that prevent organisms from optimizing all life history traits simultaneously.
Example: Organisms cannot have a long lifespan while also reproducing rapidly.
What does the Y-Model of Life History Trade-Offs illustrate?
How resources must be allocated between competing demands like reproduction vs. survival.
Explains why energy investment in one function limits investment in another.
List key trade-offs in life history.
- Current vs. future reproduction
- Offspring quantity vs. quality
- Reproduction vs. immune function
Give an example of trade-offs in humans.
Historical data from Utah shows children from larger families had lower survival rates.
Another example: French-Canadian women had lower postmenopausal mortality with more childbirths, but causation is unclear.
What methods are used for studying life history trade-offs?
- Measuring life history traits
- Manipulation experiments
What was demonstrated in the Drosophila trade-off experiment?
Fruit flies with reduced protein intake had longer lifespans but produced fewer eggs.
Demonstrates a direct trade-off between reproduction and lifespan.
How does evolutionary medicine integrate different perspectives?
It integrates genetic, environmental, and life history perspectives to understand health and disease.
Mismatches and epidemiology explain modern health issues.
