Biological Diversity BSCI 10110 1 MWRF 1 10 2 00 Dr Mark Kershner Week 2 9 9 Hypothesis of Natural Selection populations of organisms tend to look like individuals that breed the most all organisms have the potential to produce more offspring than could ever survive some individuals will survive better and produce more offspring than others because of their traits traits that are advantageous will become more common over time heritable traits are plastic can change be selected for as environmental conditions change populations change over time microevolution can result in speciation macroevolution Evolution Ch 20 22 Evidence for evolution Ch 21 as FACT observations Changes over time directly observed inferred from indirect evidence Direct observation bacterial viral resistance to drugs MRSA Methicillin resistant Staphylococcus aureus Multi drug resistance H1N1 starting to see resistance to anti virals Black vs white peppered moths Fig 21 3 21 4 industrial melanism artificial selection Fig 21 6 21 7 ancestral species of Brussels sprouts cauliflower and cabbage dog breeds Evolution inferred from observations oysters increase in size flatter shell equine horse evolution Fig 21 13 size molars toe reduction fossils of intermediate forms missing links Fig 21 12 whale evolution vestigial structures Fig 21 17 whale and boa constrictor pelvic bones bird evolution dinosaur bird Archaeopteryx 9 10 Exam a week from 9 11 Next Thursday s lecture not included on exam Confuciusornis sancti Fig 21 4 development embryological development track certain muscle masses gene groups Fig 21 15 homology homologous structures with different appearance function derived from same structure in a common ancestor Fig 21 4 analogous structures share common function but are a separate origin DNA sequencing genetic code is same for all organisms closely related organisms have a lot more similarity in gene sequences Fig 1 10 Biogeography and Convergent Parallel Evolution Biogeography species resemble nearby relatives Convergent Evolution similar environments contain similar but unrelated species local adaptation Fig 21 18 Ch 20 Microevolution requirements for evolution to occur particularly relative to natural selection causes of evolutionary change importance of fitness Variation in genes within a population without this there is nothing to be selected for without genes there is nothing to be passed on to offspring selection occurs among individuals individuals are being selected NOT the population Populations evolve mutation of genetic code is ultimate source adaptive variation is NOT acquired by individuals during their lifetime genetic traits that are not heritable likely disappear if they are not heritable 9 11 Requirements for Natural Selection variation exists variation results in differences in reproduction output survival variation must be heritable lupines shells Fig 20 7 Fig 21 2 Natural Selection is NOT the same thing as evolution it is a mechanism by which evolution can occur Natural Selection is NOT random Natural Selection acts on individual NOT species Natural Selection has NO purpose goal DNA deoxyribonucleic acid Nucleotides sugar phosphate group Bases cytosine guanine adenine thymine Base pairs AT GC specific genetic make up for a given trait genetic make up different forms of the same gene alleles outward expression of the underlying genotype trait value genotype phenotype Lamarck Fig 20 1
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