Evidence Of Evolution 2016 PDF

Evidence of Evolution - The process where changes in the inheritable traits (genes) of a species occur over time There are two types of evolution ◦ Microevolution: changes in gene frequency in a population from one generation to the next ◦ Macroevolution: the descent of different species...

Evidence of Evolution - The process where changes in the inheritable traits (genes) of a species occur over time There are two types of evolution ◦ Microevolution: changes in gene frequency in a population from one generation to the next ◦ Macroevolution: the descent of different species from a common ancestor over many generations Evolution helps us to understand the history of life. Evidence for Evolution 1) Fossil Evidence Fossils are the remains of animals or plants Layered chronologically in rock layers so deeper layers contain older fossils The fossil record shows how species have changed over time. Older fossils tend to be simpler, and more recent fossils may be more complex.  You don’t have to be a paleontologist to find fossils! Carina Helm discovered marine reptile called an ichthyosaur in B.C 2006 A giant trilobite discovered by teenagers near Toronto creek New ancient reptile found by 9 year old boy in P.E.I Michael Arsenault found the fossil older than the earliest dinosaurs at the beach in front of his family’s cottage. The fossil has been named Erpetonyx arsenaultorun Tyrannosaur tracks discovered by UBC student Darwin was puzzled... “What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern, and should include the same bones, in the same relative positions?” Bones are even similar in their number and not just arrangement. - E.g. Almost all mammals have precisely 28 skull bones & 7 neck bones, regardless of the size of their skull or length of their necks. Compare! Bat Human 2) Anatomical & Embryological Evidence Homologous structures – Structures that have similar structural elements (shape,size, number), but may have different functions. This shows that they share a common ancestor.  2) Anatomical & Embryological Evidence Analogous structures – Structures that performs the same function but do not have a common evolutionary origin WHY? - Insects & birds are only distantly related & have evolved these features independently of each other. 2) Anatomical & Embryological Evidence Vestigial structures –structures that have no apparent function and appear to be residual parts from a past ancestor  Vestigial structures in Humans Appendix Tonsils, Wisdom teeth Tailbone (Coccyx) Palmar Grasp Reflex Embryological Evidence Embryos of all vertebrates (i.e. Humans, chickens, fish) possess a short bony tail. Human embryos also have gill slits even though by Which one of these early embryos is human?? the time we are born, we do not have gills. WHY? These species shared a common ancestor & over time, the original structures were modified as each species evolved. 3) Biogeography study of how and why plants and animals live where they do Geographic distribution of organisms based on living species and fossils Similar habitats select for similar traits Ex: Beaver (North America) and capybara (South America) are distantly related rodents but they share similar body types Biogeography of camels All of today’s camels descended from the same camel ancestors. Now they live in different parts of the world, but they share similarities. Island Biogeography Darwin’s finches on Galapagos Islands all probably descended from one bird that arrived from S.A. Evolved into many types of finch species, each adapted for a different food type Adaptive radiation: a single species evolves into many new species Examples Geographically close Cacti are native only to environments more likely to be deserts in N.A., S.A., and populated by related species Central America. They are NOT found in other deserts in the world Animals found on islands often Lizards on Canary Islands closely resemble animals found on similar to lizards found in west closest continent Africa Fossils of same species found on Fossils of reptile Cynognathus coastline of neighbouring found in Africa and S.A. How? continents Continental drift! 4) DNA Evidence The more closely two species are related, the more DNA sequences they have in common Cytochrome C (oxygen-carrying protein) is found in almost every animal, suggesting that this protein was inherited from a common ancestor Evidence from DNA…Facts Humans share the following % DNA similarities: Human & Chimpanzee = 98.8% similar Human & Gorilla = 98% similar Human & Yeast = 26% similar Human & Fruit Fly = 44% similar Human & Banana = 50% similar…Lol