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Unformatted text preview: Genetics and Evolution 14/02/2008 12:37:00 ← 3 types of diversity • cultural • biological • environmental ← genes, genetics, genotypes • gene: a unit of inheritance • genetics: the science of heredity and variation • genotype: an organism’s hereditary makeup ← alleles • an allele is a particular biochemical form of a gene. Genes have multiple alleles. • Alleles can be dominant or recessive ← Phenotype is what we see, genotype is what we are ← Gregor Mendel • Alive in the early 19 th century • Lived in an abby • Worked with breeding peas • Law of Segregation – alternative versions of genes (alleles) account for variations in inherited characteristics; for each characteristic, an organism inherits two alleles, one from each parent. One of the two alleles may be dominant over the other, with it alone being expressed. The two alleles for each characteristic segregate during gamete production. • Law of Independent Assortment – the inheritance pattern of one trait will not affect the inheritance pattern of another. • Phenotype – the observed characteristics of an organism • Phenotypic plasticity and adaptive capacity Theory of evolution • Separate than the FACT of evolution • Not a force unto itself, just a statistical reality • Origins of the theory o Creationism – all biological diversity and variation originated during a single creation event James Usher – Archbishop of Ireland Usher chronology – used the Bible to create a chronology of creation events. o Catastrophism – sudden and short violent events throughout the earth’s history caused mass extinctions and changes to the earth’s ecosystems. William Buckland – first person to ever scientifically describe a dinosaur. Uniformitarianism/gradualism – process that happen now, happened in the past. o Transformationism – also known as gradualism and transmutation, posits that species change over time, and that the processes we observe now are the same that occurred in the past (uniformatarianism) Lamarck (Lamarckian evolution) – species change, but they change to become more complex Chambers – first to come up with an evolutionary tree Charles Darwin – 1809-1882 Naturalist On the Origin of Species… “Darwinism” • artificial selection • what about in nature?...
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- Spring '08
- Evolution, Homo Sapiens, homo sapiens sapiens, Homo erectus HOMO, Homo Erectus Africa