Presentation on theme: "AP Biology 2006-2007 Chapter 15.3 Evidence of Evolution Dodo bird."— Presentation transcript:
AP Biology 2006-2007 Chapter 15.3 Evidence of Evolution Dodo bird
AP Biology Fossil Record The fossil record is incomplete but provides some evidence about the history of the earth. Fossils can show the progression of ancient, primitive organisms to modern day forms. TrilobiteLeaf
AP Biology Fossil Record: The history of life on Earth can be partially constructed by dating (age) and comparing fossils - Relative Dating: approximate age based on position on the rock layers - Absolute Dating: Exact age determined by radioactive dating
AP Biology Extinct: Trilobite (crustacean) Ammonite (mollusc) Similar to present-day species: still around FishScallop (mollusc)
AP Biology Comparative Anatomy A. Homologous structures: Homologous structures develop from the same tissues, but have different forms with different functions. Same origin -- different form/function The similarity is due to having derived from the same common ancestor. Example: Bone structure of arms and legs in all vertebrates.
AP Biology B. Analogous Structures: Different origin but have similar function
AP Biology Vestigial structures Modern animals may have structures that serve little or no function remnants of structures that were functional in ancestral species evidence of change over time some snakes & whales show remains of the pelvis & leg bones of walking ancestors eyes on blind cave fish human tail bone
AP Biology Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures?
AP Biology Comparative embryology Similar embryological development in closely related species all vertebrate embryos have a gill pouch at one stage of development fish, frog, snake, birds, human, etc.
AP Biology Molecular record Comparing DNA & protein structure universal genetic code! DNA & RNA cytochrome C (respiration) protein structure hemoglobin (gas exchange) protein structure Evolutionary relationships among species are documented in their DNA & proteins. Closely related species have sequences that are more similar than distantly related species.
AP Biology Comparative hemoglobin structure Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans 1002030405060708090100110120 LampreyFrogBird Dog MacaqueHuman 32845 67 125
AP Biology Building “family” trees Closely related species (twigs of tree) share same line of descent until their recent divergence from a common ancestor
AP Biology VIEW: http://www.pbs.org/wgbh/evolution/libr ary/07/3/real/l_073_47.html http://www.pbs.org/wgbh/evolution/libr ary/07/3/real/l_073_47.html
What data from whole genome sequencing can tell us about evolution of humans
Macroevolution – evolution on a large scale (above population level)
How fast is evolution? How fast do organisms change? Gradualism Punctuated Equilibrium
Gradualism Organisms go through gradual and continuous change
Punctuated Equilibrium Organisms go through fast periods of change, followed by long periods of no change (according to fossil record)
Patterns of Evolution: 1. Convergent Evolution Convergent Evolution: When 2 or more unrelated species become more similar due to similar adaptations to their environment.
Convergent evolution Flight evolved 3 separate times –evolving similar solutions to similar “problems”
Divergent Evolution: when related species become more different as they adapt to different environments Divergent evolution leads to Adaptive Radiation Patterns of Evolution: 2. Divergent Evolution-Adaptive Radiation
Adaptive Radiation Process by which a single species or small group of species evolved into several different forms that live in different ways
Coevolution Predator-prey relationships Parasite-host relationships Flowers & pollinators Process by which two species evolve in response to each other over time