BIOL 1200 2025 8 Evol History, EvidenceStdnts

Page 1: Introduction to Evolution

• Title: EVOLUTION

• Subtitle: Only here, it seems.

• Theme: The puzzle of biodiversity

Page 2: Public Perception of Evolution

• Evolution tends to face skepticism, with some views considered outrageous.

• Emphasis on evidence in science rather than belief.

• Importance of evolution in understanding life.

Page 3: The Significance of Evolution

• Quote from Theodosius Dobzansky: "Nothing makes sense in biology except in the light of evolution."

Page 4: Definitions of Evolution

• Evolution defined as:

  • Descent with modification

  • Changes in allele frequencies across generations.

• Fundamental property of populations and species.

Page 5: Historical Context

• Charles Darwin:

  • Born in 1809 to a wealthy British family.

  • Briefly studied medicine at Edinburgh.

  • Attended Cambridge for ministry studies.

  • Developed an interest in beetle collection.

  • Served as the ship's naturalist on HMS Beagle starting in 1831, which established his scientific reputation.

Page 6: Darwin in 1840

• Reference to Darwin's status in 1840 as depicted in Price 1996's publication.

Page 7: Darwin's Observations and Insights

• After returning from the voyage, Darwin was unwell but wealthy.

• Noticed geographic variations and organism similarities within regions.

• Struggled to comprehend adaptation until reading Malthus in 1838, which inspired the natural selection concept.

• Wrote a secret essay in 1844 detailing his thoughts.

Page 8: Alfred Russel Wallace

• Recognized as a prominent figure parallel to Darwin in discussing natural selection.

• Wallace worked in regions such as Indonesia and Malaysia.

Page 9: The Presentation of Natural Selection

• In June 1858, Wallace shared his manuscript outlining natural selection with Darwin.

• Both presented their findings to a major scientific society in London.

• In 1859, Darwin published "Origin of Species":

  1. Documented evidence for evolution.

  2. Explained natural selection as the primary mechanism for adaptation.

Page 10: Acceptance of Evolution

• Evolution quickly gained acceptance among scientists.

• Natural selection faced skepticism until Mendel's genetics were integrated into evolutionary theory.

Page 11: Evidence of Evolution vs. Special Creation

• Evidence for evolution in contrast to the belief of "special creation" (supernatural origins).

  1. Homologous similarities:

     • Traits shared among organisms due to common ancestry, inherited through descent.

     • Different from convergent functional similarities.

Page 12: Examples of Homologous Structures

• Similar limb structures in tetrapod vertebrates (e.g., humerus, radius, ulna) exist despite different functions.

• Molecular characteristics also show sets of homologies.

Page 13: Vestigial Organs

• Vestigial organs are features that have reduced function but are shared with ancestors.

  • Examples include the pelvic girdles in snakes and whales.

  • Also noted are molecular vestiges.

Page 14: Fossil Evidence of Evolution

• Transitional fossils demonstrate the hind limb loss in ancient marine mammals:

  • Indohyus, Pakicetus, Ambulocetus, Basilosaurus, Bowhead whale.

  • Key structures include tibia, femur, pelvis.

Page 15: Biogeographic Patterns

• Importance emphasized by Darwin and Wallace:

  • Related species often found in close geographical proximity, such as Galapagos birds.

  • Strata fossils show progression and similarity with adjacent layers, supporting descent with modification.

Page 16: Niche Adaptations

• Observance of niche similarities in placental mammals versus Australian marsupials (e.g., different burrowers and climbers).

• Highlight of convergent evolution reflected in ecosystem adaptations.

Page 17: Direct Observations of Evolution

• Real-time observations of evolution:

  • Examples include Peppered moths, Darwin’s finches, and sticklebacks.

  • Phenotype variations observed in Gasterosteus aculeatus, changes correlating with environmental factors noted.

Page 18: Evolution in Action

• Rapid evolution of armor in specific populations of sticklebacks observed over time.

• Frequency data showing the shift in morph types during the observation period.

Page 19: Resistance Develops in Nature

• Increases in antibiotic resistance correlated with the frequency of antibiotic use in Finland.

  • Highlighted by the rise in infections among middle ear bacteria with increased beta-lactam usage.

Page 20: Experimental Evolution

• Artificial selection examples presented by Darwin:

  • Breeders influencing traits in dogs, cabbages, and pigeons.

  • Insights into speciation observed experimentally in controlled conditions.