Evolution and Natural Selection

Adaptive Radiation

• Evolution of multiple species from a common ancestral species, resulting in ecological diversity
• Example: Darwin's finches on the Galapagos Islands, adapting to their environment through changes in beak shape and size, leading to diverse species
• Evidence for convergent evolution, where unrelated species develop similar traits in response to similar environmental pressures

Artificial Selection

• Selection process where species with favorable traits are chosen, resulting in rapid change within one generation
• Illustrates the principles of natural selection and descent with modification
• Example: Production of numerous breeds of dogs through artificial selection
• Provides evidence supporting natural selection as the mechanism for evolution

Evolutionary Forces

• Four main forces driving evolution:
  • Natural selection
  • Mutation
  • Gene flow (migration and reproduction)
  • Random genetic drift

Natural Selection in Human Populations

• Human populations adapt to environmental pressures, such as climate
• Examples: Larger body weight and shorter limbs in colder environments, and smaller body weight and longer limbs in warmer environments
• Human modification of environments has relaxed selection on many traits, such as access to clean water, medicine, and a reliable food supply

Medicine and Evolution

• Evolutionary medicine: uses evolutionary theory to understand health, disease, and anatomy
• Examples: Emerging diseases, origins of disease, treatment of disease, and antibiotic resistance
• Evolutionary trade-offs, such as skin pigmentation (UV protection vs vitamin D synthesis), female pelvis (bipedal locomotion vs birthing), and descended larynx (speech vs choking)

Conservation Biology

• Low population numbers result in low genetic variation, making populations vulnerable to extinction
• Endangered populations are vulnerable to high death rates due to selective pressures, such as disease

Agriculture and Horticulture

• Applied evolution: humans use evolutionary principles to improve crops and animal stocks
• Examples: Development of new crop varieties and animal breeds

Weeds and Feral Animals

• Dispersal of invasive species, leading to crop mimicry and competition

Forensics

• Interpreting and analyzing DNA evidence to understand population profiles and solve crimes

Human Behaviour

• Human behavior shares similarities with that of other animals, including emotions, relationships, and parental care
• Examples: Mate choice and long-term pair bonds, similar to those seen in other animals

Evolution Essentials

• Key components of evolution:
  • System of reproduction
  • Inherited variation
  • Changing environment
  • Selective pressures
  • Differential reproductive success (fitness)