* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Some Evidence of Evolution
Sexual selection wikipedia , lookup
Natural selection wikipedia , lookup
Organisms at high altitude wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Evolutionary landscape wikipedia , lookup
Population genetics wikipedia , lookup
Sociobiology wikipedia , lookup
Evolving digital ecological networks wikipedia , lookup
Catholic Church and evolution wikipedia , lookup
Dawkins vs. Gould wikipedia , lookup
Evolutionary developmental biology wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Evolutionary mismatch wikipedia , lookup
Theistic evolution wikipedia , lookup
Evidence of common descent wikipedia , lookup
Punctuated equilibrium wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Evolutionary Trees in the Ecological Garden Chapter 2 How did we get so may different organisms? Non Evolutionary systems • • Biblical, creationist system Lyle view on change (pre Darwin) Evolutionary systems 3. Lamarckian system 4. Evolution by natural selection (Darwin) Biblical, creationist view • Life arose by special creation • Species do not change Organisms formed as we find them today Lamarckian system No extinctions, many origins •Change is linier from simple to complex •Very much a creationist view Lye View • Extinctions take place • Creations take place • Organisms do not change Darwin’s Evolution • Life on earth is ancient • Species change over long periods of time time a descent with modification by means of natural selection • Species are related to each other as ancestordescendant Link to virtual tour Darwin's house and writings Darwin Vs Lamarck Theories of Change Over Time 1. 2. An evolutionary relationship exists among groups of organisms Reflects single unique history of life 3. Change over time from many, non related starting points Speciation • Speciation: when new species evolve from existing species • Speciation is represented as a “fork in a branch • Extinction “prunes” branches from the evolutionary tree Evolutionary Anastomosis: Branch Evolution of longlasting species fusion: Rare and IMPORTANT Phylogeny & Parsimony • Many patterns are possible for each evolutionary tree • Less complicated explanations more likely to be correct – In evolutionary biology, phylogenies that require fewer evolutionary transitions more likely to be correct Four transition states or one? Parsimony: Let’s make a tree Who is the close relation? Less complicated explanations more likely to be correct • Identify traits shared by some, but not all of the organisms – – – – Fur Live offspring Teeth Flight Which would you pick? Us the tree with the fewest transition events, It may not be correct, but it is more probable that a more complicated proposal. Characteristic transitions Selection for flight – Twice !! Selection for fur Selection for teeth •Selection for live births rather than eggs Make a Tree, make it simple Homology and Analogy • Homology (modern sense): similar by descent or ancestry • Analogy: similar not by descent – In conversation: ‘let me compare thee to a summers day’ – In biology: similar selection pressures produce similar adaptations • E.g. desert plants in N. America share many water saving features with other desert plants Important Trees 1. Three Domains of life: Above kingdoms!! 2. Each domain has been separated into seven kingdoms Bacteria Archaea Universal ancestor Eukarya Kingdoms - now there are Eight? Looking for LUCA (the Last Universal Common Ancestor How many kingdsoms? Six kingdom taxonomists Seven kingdom taxonomists More that seven kingdom taxonomists Three domains rule! link Origin of Eukaryotes: Endosymbiosis Theory Anastomosis link Eukaryotic nuclei do not share recent ancestors with the genes of their organelles, but rather that of bacterial genomes Vertebrate forelimbs Trees and evolution • When we cluster organisms based on similarities, we find other similarities: There are no insects with calcified bones, or bats with feathers Biological classification is a reflection of evolutionary history Fossil evidence & patterns of change Fossils provide information that makes it possible to reconstruct evolutionary sequences over time What about fossils? Fossils provide three types of evidence for evolution • Evidence of extinction • Evidence of change of species through time • Evidence of age of life Change through time: Transitional fossils • Fossils species intermediate between modern living forms • Fossil species intermediate between older and younger fossils, or older fossils and modern forms Biogeographic patterns • Evolution is local, and species migrate from their point of origin • There are “hotspots” for change in the warm tropical regions • link Human embryo with tail Developmental patterns & evolution Comparative model • If you built a flying limb from scratch, you would design it differently than you would design a swimming or grasping or running limb • The similarity of structure despite very different function suggests similarity of origin • Adaptations are the response to natural selection Homology • A similarity between species that is not functionally necessary. – Structural homology – Developmental homology – Genetic homology Genetic Homology • Structural homologies are similar because they share developmental homology • Developmental homology is the result of genetic homology ‘Universal’ genetic codeOther homology examples Genetic homology in homeodomain eye genes Thought question • Biomedical researchers often seek treatments for human disease by doing experiment in other species (e.g. mice) • How successful would they be if mice and humans did not share numerous homologies? Examples of vestigial traits Also: Your appendix Wisdom teeth Goose bumps Vestigial traits can be: • Structural – Tail bone in adult humans • Developmental – Embryonic tail Vestigial Genes • Genetic – Pseudogenes: nearly normal genes that are not transcribed to protein – E.g., psi-alpha locus of hemoglobin – Resembles that alpha locus but has a mutation that stops transcription Homoplasy: convergent evolution • Shared characteristi cs of non related lines