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EK 1A4

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EK 1A4

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  1. EK 1A4 Biological evolution is supported by scientific evidence from many disciplines, including mathematics

  2. Scientific evidence of biological evolution uses information from: geographicalgeologicalphysicalchemicaland mathematical applications

  3. geography and the continental drift can support evolution • Island species usually are closely related to species on nearby continents even if the environments are different. • Early island colonizers often evolve into diverse species because other, competing species are rare. • Geographic proximity is not always a good predictor of evolutionary relationships, however. • Continents are constantly moving because of continental shift – although the movement is slow (several centimeters per year), the configuration can and has changed considerably over geologic time. Ex; southern beech tree which is found in Chile, Australia and New Zealand.

  4. Molecular, morphological and genetic information of existing and extinct organisms add to our understanding of evolution

  5. The fossil record indicates that horses have evolved from small, forest-dwelling animals to the large and fast plains-dwelling species we see today. • For many years, horse evolution was given as an example of constant evolution through time, now fossils show rates of evolution have varied widely with long periods of little observable change and some periods of great change. • Characteristics that have changed are: size, reduction in the number of toes(four in front, 3 in back, to one toe today), tooth size and shape(simple to large and complex)

  6. Morphological homologies vsvestigial structures

  7. Homologous vs analogous • Homology • Traits inherited by two different organisms from a common ancestor • Analogy • similarity due to convergent evolution, not common ancestry

  8. What do we call structures like this? (Different organisms with similar structures) homologous structures • What does this mean from an evolutionary perspective? All structures derived from the same body part of a common ancestor • What is a vestigial structure? Describe 3 types of vestigial structures. Structures that have no apparent function, but resemble structures their ancestors possessed – muscles in humans to wiggle ears, boa constrictors have pelvic and rudimentary leg bones, baleen whales have pelvic bones

  9. Fig 21.12

  10. Critique of National Geographic article • Graph one of Hardy Weinberg problems •