Evolution 3

Evolution and Human Biology

Presenter: Fiona O'Shea, School of Human Sciences, University of Western Australia

Demonstrate understanding of evolutionary principles and processes.
Utilize evolutionary theory to explain the modern human condition and the challenges we face.

Caused by differential survival and reproduction.
- Variation: Differences among individuals in a population.
- Differential Reproduction: Some individuals with advantageous traits reproduce more successfully.
- Selection: Environmental pressures influence which individuals survive.
- Heredity: Traits are passed on to offspring.

Biotic Factors:
- Competition: Struggle for resources among individuals.
- Predation: Impact of predators on survival.
- Disease: Influence of parasites and pathogens.
Abiotic Factors:
- Climate: Effects of temperature, precipitation, etc.
- Topography: Influence of physical geography on living conditions.
- Habitat: Type of environment organisms live in.
Overall Process:
- Acts on phenotype across all life stages and can influence populations across many generations.
- Result: Genetic change in a population over generations.

Genetic adaptations to environmental changes:
- High Altitudes: Adaptations in Tibetan and Andean populations.
- Arsenic Tolerance: Observed in Puna Indians of the Argentinian Andes.
- Lactose Tolerance: Emergence in agricultural communities.

Cold Environments:
- Larger body weight and shorter limbs enhance heat retention.
Warm Environments:
- Smaller body weight and longer limbs enhance heat dissipation.

Urban dwellers likely possess DNA variants granting resistance to infections.
- Increased resistance to diseases such as TB and leprosy observed in urban populations.
- Regions in Africa exhibit resistance to HIV.
Environmental modifications have relaxed selection pressures:
- Availability of clean water and healthcare services.
- Increased reliability of food supply.

Evolutionary Medicine: A field applying evolutionary theory to health and disease.
- Understanding the rapid evolution of emerging diseases (e.g., H1N1, SARS, COVID-19).
- Investigating disease origins helps shape research (e.g., HIV related to SIV).

Challenges like antibiotic resistance impacting treatment effectiveness.
Implications for vaccine development and drug formulation:
- Use of drug cocktails and alternative sourcing due to resistance concerns.

Transmission modes impact disease effects:
- Malaria (vector-borne), waterborne diseases (cholera, dysentery), airborne diseases (common cold).

Historical gene advantages can be detrimental today:
- Hereditary conditions like hemochromatosis influenced by high iron diets.
- Thrifty gene linked to obesity and metabolic syndrome.

Skin Pigmentation:
- Balancing UV protection and vitamin D synthesis effectiveness.
Female Pelvis:
- Compromise between bipedal locomotion and the birthing process (obstetric dilemma).

Utilizing evolutionary principles in DNA analysis:
- Assessing matches between crime scene samples and population profiles.

Application of evolutionary concepts to enhance crop yields and livestock.
- Practices involve selective breeding known as "applied evolution."

Evolutionary heritage reflected in human behavior:
- Emotional responses, familial relationships, parental care, mate selection, and long-term partnerships.

Core components of evolution include:
- Reproductive systems, inherited variations, changing environments, selective pressures, and varying reproductive successes (fitness).

"Nothing in biology makes sense except in the light of evolution" - Theodore Dobzhansky.