Evolution: a journey into where we're from and where we're going.
Doctrine of the Creation of the Animals (1550).
The fossil record shows life’s natural history with successions and extinctions through different geological eras such as Quaternary, Tertiary, Cretaceous, etc.
Key species transitions include arthropods, chordates, and mammals.
Organisms adapt to their environments by acquiring traits during their lifetime.
Disuse leads to loss of parts (e.g., tapeworms).
Constant use of an organ increases its size.
Charles Darwin (1809-1882): Proposed evolution by natural selection.
Collected evidence on the HMS Beagle (1831-1836), observing biodiversity in the Galapagos Islands.
Notable species include native armadillos and Glyptodont fossils.
Darwin collected 14 species of finches which he later realized were variations of the same species.
Finches adapted to different food sources, leading to varied beak sizes and shapes:
Large Ground Finch, Small Ground Finch, Warbler Finch, etc.
Evidence of differential survival: finches with beneficial beak traits survived better.
Variation in traits; overproduction of offspring; competition; differential survival and reproduction.
Traits that improve survival accumulate.
Changes in trait frequencies due to chance, such as founder effects and bottleneck effects.
Movement of alleles due to migration; mutations introduce new genetic variations.
Illustrates changes from ancestral species to modern organisms.
Similar structures in different species indicate common ancestry (e.g., limbs of humans, cats, whales, and bats).
Structures that serve little to no function in modern species reflect evolutionary changes (e.g., human tailbone, pelvis in whales).
Molecular records through DNA comparisons show evolutionary relationships.
New species arise through isolation:
Allopatric: geographic isolation.
Sympatric: reproductive isolation despite shared habitats.
Mechanisms include behavioral, temporal, and mechanical isolation, and gametic isolation.
Agents of evolutionary change include natural selection, genetic drift, mutations, gene flow, and non-random mating.
Evolution is a continuous process, shaping life on Earth and influencing the characteristics of species.