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.

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