EVIDENCE THAT CHALLENGED THE ASSUMPTION THAT LIFE IS STATIC AND UNCHANGING Evidence for Change in the Patterns of Life’s Biodiversity Over Time and the Relatedness of Species

BIOGEOGRAPHY – The study of the distribution of organisms that live on the earth Biodiversity is High! –At least 1.75 million species on earth have been described and given names. –Approx. 1,000,000 animals, ¾ of which are insects –Approx. 250,000 plants –Approx. 69,000 to 100,000 fungi About 10,000 new species are reported each year –On internet visit: references/factsheets/factshee t1.PDF references/factsheets/factshee t1.PDF

Marsupials and Placental Mammals and their Ecological Counterparts

African Euphorbs and the American Cactus: Ecological Counterparts

Comparative Anatomy: Embryology Human embryos have pharyngeal arches, a two- chambered heart, and a tail which disappears before birth! –Pharyngeal arches in fish develop into the gills and the jaw. –In humans, pharyngeal arches do not develop into gills, but into the lower jaw, hyoid bone, and larynx

Comparative Anatomy: Embryology Cat and human embryos in the tail bud stage. A cat embryo is shown on top, a human embryo below. Note the post- anal tail in both, positioned at the lower left below the head of each. The human embryo is about 32 days old.

Comparative Anatomy: Vestigial Structures

Comparative Anatomy: Homologous Structures

Fossil Record Nicolaus Steno - published a work in 1669 dealing with the question of "Why is a solid in a solid?" He was puzzled by the existence of 'tongue stones' which were found embedded in rock, but which bore a strong resemblance to sharks teeth. He proposed that some forms of rock (sedimentary rock) were not always hard but were formed by from a slurry of mud, rock, sand, and other materials which had encased teeth from sharks before some geological process had transformed the entire lot into stone. He was one of the first people to recognized that fossils were the castings and/or physical remains of life forms that had existed in the past. For more information see Gould, S. J., The titular bishop of Titiopolis. Chapter 5 in Hen's Teeth and Horse's Toes,

Fossil Record: Extant and Extinct

Artificial Selection: Breeds of Dogs

Artificial Selection: Varieties of Plants

Major Paradigm Shift in Life Science By the beginning of the 19th century, it was becoming apparent that species represented potentially changeable or malleable entities. Under the proper conditions, pre-existing species might give rise to a new species! If so, change in the pattern of biodiversity of life could occur (A.K.A. evolution). If evolution (at the time called transmutation) did occur then by what mechanism? Entering the fray during the 18 th and 19 th centuries: Georges Buffon, Erasmus Darwin, Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck, Charles Lyell, Charles Darwin, and Alfred Wallace.