Human Biology Exam 4: Evolutionary Pressures

Human Biology in the Modern World: Are We Still Evolving?

• Human biology is still evolving, influenced by modern pressures such as environment, diet, lifestyle, and disease.
• Exam 4: December 14, 1-3 PM, Campus Center Auditorium, same format and length as Exam 3, material covered since Exam 3, not cumulative, includes videos.

Evolutionary Pressures

• Evolutionary pressures are changing
• Factors include: environment, diet, lifestyle, and disease.

Reduced Selection Pressures

• Technology and medicine have eased some selection pressures.
• Humans create comfortable microenvironments, allowing alleles that previously would have been detrimental to be passed down.

Myopia

• Myopia is reduced ability to see distant objects clearly.
• Nearsightedness is associated with decreased visual acuity important in the evolutionary past.
• Myopia can be easily corrected by glasses or contacts.
• Is myopia a selective pressure today?

Dental Caries

• Environmental and genetic factors impact dental cavities (cavities)
• Untreated cavities increase mortality risk in the past.
• Untreated cavities are linked to poor health outcomes.

Phenylketonuria (PKU)

• PKU is a metabolic disorder. PKU causes decreased ability to break down phenylalanine.
• PKU patients need a special diet to prevent dangerous phenylalanine builds up.
• PKU has been addressed with widespread newborn testing and diet interventions since the 1960s.

Type 1 Diabetes

• "Juvenile" diabetes has seen increased incidence in recent years.
• Relaxed selective pressure from modern medical care has contributed to this.
• Type 1 diabetes in the past had lower survival rates
• Type 1 diabetes is a result of an autoimmune response targeting and destroying insulin-producing cells in the pancreas.
• Patients require insulin for survival.

Climate and Evolution

• Are humans evolved to be adaptable to environmental changes such as climate?

Stress

• Elevated, chronic stress is associated with poor cardiovascular and health outcomes.
• Stress impacts aging.
• Stress is linked to health disparities.

Obesity

• Obesity is a form of malnutrition
• Thrifty phenotype and genotype play a role in obesity
• Food insecurity and metabolic diseases are linked to obesity

Culture and Evolution

• Culture has impacted selective pressures on humans.
• Examples include: food production, clothing, housing, technology, education, and medicine.
• How will cultural factors continue to impact future generations?

Understanding Human Variation

• Genetic variability in humans is low compared to other species.
• Evolutionary forces in human history can lead to adaptations to local conditions.
• Race is an incomplete descriptor of biological variation.
• Complex interactions exist among biological, cultural factors, and the environment.

This quiz focuses on the current state of human evolution influenced by modern environmental and lifestyle factors. It covers key concepts related to evolutionary pressures, myopia, dental health, and the impact of technology on selection pressures. Prepare to explore how these factors shape our biology today.