Darwin and Wallace's Theory of Evolution

Darwin and Wallace's Theory of Evolution

• Humans share a common ancestor with a simple organism.
• Natural selection: Organisms with favorable traits survive and reproduce, passing on those beneficial genes.
• Genetic information is inherited from ancestors.
• Two key evolutionary principles: inheritance and variation.
• Physical and behavioral traits (e.g., personality) are inherited.
• Variation comes from genetic differences, enabling adaptation to environments.
• Inherited traits include hair/eye color, personality, memory capacity, and sleep patterns.
• Genes, like the C-O-M-T gene, influence working memory and learning.
• The C-O-M-T gene impacts dopamine levels in the prefrontal cortex.
• Observable traits are called phenotypes.
• The principle of adaptation suggests advantageous genes are passed on for survival.
• Evolution takes decades to thousands of years.
• Types of Natural Selection:
  • Directional: Traits shift from one extreme to another (e.g., a longer lizard tail).
  • Stabilizing: Favors moderate traits (e.g., medium-length cat tail).
  • Diversifying: Favors two or more extremes (e.g., small and large beaks).
• Natural selection aims for maximum offspring production, not just survival.
• Natural Selection Strategies:
  • Kin selection: Helping relatives to propagate shared genes.
  • Reciprocal altruism: Helping others to receive future help.
• Supporting evidence includes biogeography, fossils, divergent/convergent evolution, comparative embryology, and molecular biology.

Human Evolution

• Human evolution started 7 million years ago, diverging from chimpanzees.
• About 20 early human species existed, but most went extinct.
• Homo sapiens (modern humans) are the only surviving species.
• Shared traits include large brain capacity, tool use, smaller teeth than apes, and bipedalism (walking upright).
• Humans have the highest brain-to-body mass ratio.

Genes and Genetics

• DNA exists in chromosomes.
• Genes are specific locations on chromosomes.
• DNA is composed of proteins (adenine, thymine, cytosine, guanine).
• A genotype is an organism's complete set of genetic material.
• A phenotype is an organism's observable characteristics.
• DNA, a double helix, was discovered in 1953.
• DNA's four pairs (A-T; C-G) carry genetic information.
• There are 23 chromosome pairs in a human genome.
• DNA replication is nearly error-free during reproduction.
• Telomeres are chromosome ends associated with cell aging.
• Humans have 22 pairs of non-sex chromosomes and one pair determining sex.
• XY chromosomes indicate male, XX chromosomes indicate female.

Explore the foundational concepts of evolution as presented by Darwin and Wallace, including natural selection, inheritance, and variation. Understand how traits are passed down through generations and the impact of specific genes on behavior and adaptation. This quiz encapsulates key principles that define evolutionary theory.