Evolution Evidence of change The fossil record Similarities in body structure Similarities in early development Similarities in chemical composition Distribution of species

Paleontology Study of prehistoric life Fossils preserved remains or traces of organisms; evidence of past life

The Fossil Record Fossils and their placement in rock formations and sedimentary strata Paleontology

How fossils are formed Paleontology

Geology Estimate of fossil’s age in comparison with other fossils Layers may not have been deposited horizontally or may have been overturned Radiochemistry Age of the sample is calculated based on the amount of radioactive elements contained C14  N14 upon an animal’s death C14>C12 = older organisms K40 for older samples nes/IIIAchronology.shtml Paleontology

Fossils link the present with the past Baleonoptera musculus (blue whale) Modern marine mammal Basilosaurus “king lizard” w/ 0.5m hind legs, w/ some bones similar to those of land mammals Ambulocetus natans “walking whale that swims” Skeletons found in Pakistan Has a long, low body w/ short, powerful limbs Descended from land-living carnivorous hoofed animals Paleontology

Problems with the fossil record 1. Fossils form by chance 2. Quality of fossils varies 3. Fossil reconstruction requires thorough knowledge of anatomy 4. Dating of fossils is achieved through various methods Paleontology

Comparative Embryology Similarities in early development Closely-related organisms have similar stages in embryonic development 1. Tail 2. Pharyngeal slits/pouches /arches 2.html Similar genes at work Similarities in early development Shared heritage from a common ancestor!

Comparative Anatomy Similarities in body structures Similar structures Homologous Similar structure, different function Due to common ancestry Analogous Similar appearance and function Different origins

Similarities in body structures and evolution Divergent evolution or adaptive radiation Common origin Descendants appear different externally but are similar internally Convergent evolution Different origins Descendants independently evolve similarities when adapting to similar environments Comparative Anatomy

Comparative Anatomy

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Vestigial structures structures that are of marginal or little use to an organism e.g. coccyx and wisdom teeth in humans, hipbones and pelvis in whales, anal spurs in pythons and boas evolution is a remodelling process: ancestral structures may be modified as they take on new roles KqBdscqI/AAAAAAAAABQ/KWFe8Ks8Oic/s1600/whale- vestigial-structure.jpghttp://3.bp.blogspot.com/-KAdBIaT796A/Ta- KqBdscqI/AAAAAAAAABQ/KWFe8Ks8Oic/s1600/whale- vestigial-structure.jpg, Comparative Anatomy

Biochemistry and Molecular Biology Similarities in chemical compounds Species pairs% difference in nucleotide sequences & chimpanzee A 2.5 & gibbon B 5.1 & old world monkey C 9.0 & new world monkey D 15.8 & lemur E 42.0 ABC DE Similarity of DNA b/w individuals of a species: related individuals > unrelated individuals Two spp. judged to be closely related by other criteria have a  proportion of their DNA in common than more distantly related spp

***Hemoglobin: protein that transports O 2 in blood Central dogma of mol bio: DNA  RNA  proteins  Structure of proteins dictated by DNA sequence  Similar proteins ~ similar DNA sequence *** Biochemistry and Molecular Biology

Similarity of chemical compounds sequences copied from a common ancestor common genetic code passed on along all the branches of evolution Degree of relatedness Biochemistry and Molecular Biology

Biogeography Distribution of species in space and through time Gondwana broke up around 160 MYA eventually forming modern Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent

Modern species present on a land mass evolved from ancestors that inhabited those regions. species are not distributed only according to where they can survive

Islands have many endemic species that are closely related to species of the nearest mainland or neighboring island.

Islands have many endemic species that are closely related to species of the nearest mainland or neighboring island.

Islands have many endemic species that are closely related to species of the nearest mainland or neighboring island.

Wallace Line - imaginary line separating ecozones of Asia and Wallacea. West of the line are found organisms related to Asiatic species; to the east, a mixture of species of Asian and Australian origin is present.