Lecture Notes: Evolutionary Biology and Genetics

General Concepts

• Biological Evolution: Defined as changes in properties of groups of organisms over generations.
  • Populations change over time.
  • Individuals experience natural selection.

Principles of Evolution

• Genes:
  • Discrete units that are real and inherent.
  • Mendelian genetics integrates into population genetics.
• Uniformitarianism:
  • Concept from Lyell's work.
  • Processes observed now occurred in the past, allowing extrapolation of data.

Evolutionary Processes

• Evolution as a Population Process:
  • Emphasizes changes in populations rather than individuals.
• Monophyletic Group:
  • Defined as a set of taxa deriving from one common ancestor.
  • All descendants share a common ancestor.

Historical Theories

• Acquired Traits:
  • Lamarck's idea that traits acquired in a lifetime can be passed to offspring.
• Tree of Life:
  • Eukaryotes share a more recent common ancestor with Archaea.

Phylogenetics

• Synapomorphies:
  • Shared derived characteristics crucial for understanding phylogenetic relationships.
• Parsimony in Phylogenetic Trees:
  • Trees with the fewest evolutionary changes are most parsimonious.

Genetic Drift and Speciation

• Molecular Clock:
  • Tends to overestimate divergence times unless calibrated by fossils.
• Phylogenetics and Taxonomy:
  • Ancestral relationships determined by evolutionary changes.
  • Genesis refers to evolutionary changes within a lineage.

Comparative Anatomy

• Homologous Structures:
  • E.g., human and bird forearm bones share common ancestry.
• Convergent Evolution:
  • Similar traits in distantly related organisms, e.g., eyes of vertebrates and cephalopods.

Evolutionary Synthesis

• Modern Synthesis:
  • Combines genetics with evolutionary theory.
  • Accounts for genetic drift and synthesizes principles of population biology.

Miscellaneous

• Special Creation:
  • Early belief in species created independently, e.g., Aristotle's views.
• Genetic Drift:
  • Random changes in gene frequencies, not inherently adaptive.

Questions & Concepts

• Populations with common ancestors form the basis of taxonomic groups.
• Speciation often involves a combination of genetic factors and evolutionary pressures.