2PhylogenyThe history of the evolution of a group of organisms
3Adaptation – an inherited trait or set of traits that improve the chances of survival and reproduction of an organismEvolution – the cumulative changes in characteristics of a population in successive generations
4Theories of Evolution Lamarck Law of Use and Disuse: organisms can change their body features during their lifetimes to satisfy their needs.
5Theories of Evolution Lamarck 2. Acquired characteristics are inherited:Those characteristics changed during the lifetime of an individual can be passed on to offspring
6Ex) Giraffes are able stretch their necks to reach leaves and this trait is passed on to their offspring.
7Darwin Job was a ‘naturalist’ – recorded and sampled new species Voyaged on the Beagle to the Galapagos Islands
8Darwin observed many species Ex) Finches had adapted to eat blood, use sticks in holes, drill holes
9Darwin He also noticed curious species: Iguanas that ate algae from oceanFlightless cormorants
10DarwinAssumed that all species evolved from a common ancestor, probably from the mainlandEx) armadillo evolved from glyptodont
11Darwinproposed that evolution occurred by natural selection and published his theory in 1859
12Another scientist Alfred Wallace had similar ideas
13Theory of Natural Selection Overproduction – more offspring produced than surviveStruggle for existence – organisms compete within and between species
14Theory of Natural Selection 3) Variation – exists in any population and the variations are passed on to the next generation (genetic differences)
15Theory of Natural Selection 4) Survival of the Fittest – surviving organisms are ones better able to compete, survive and reproduce. The others die without leaving offspring (natural selection)
16Theory of Natural Selection 5) Speciation – over numerous generations, new species arise by accumulation of inherited variations of traits; considered new species when members cannot interbreed with original species.
17Key ConceptThose organisms that live long enough to REPRODUCE will pass their DNA for the ‘desirable’ traits onto their offspring.Those organisms less suited will die before reproducing.The population becomes more fit
18Giraffes Began with short necks Those that were BORN with slightly longer necks got more foodCould grow stronger to outrun predators, and survived to have babies!
19How do new traits appear? MutationSexual reproduction produces new combinations
32ConvergenceVery different species may also develop similar adaptations due to similar needs in their environmentEg. Squid and human eye
33Adaptive Radiation Or divergence Similar species become quite different due to differing environmental needs
34Two Versions of Evolution Gradualism: species gain small changes with timePunctuated Equilibrium: new species born suddenly with better adaptation- This adaptation rapidly becomes the only one in the population
47Evidence for Evolution Comparative BiochemistryRecent advances in DNA profiling and protein sequencing has allowed us to study the similarities in common molecules
48PrimateNo. Of Amino Acids Different From HumansChimpanzeeIdenticalGorilla1Gibbon3Rhesus Monkey8Squirrel Monkey9
49Evidence for Evolution Biogeography – study of geographical distribution of plants and animalsTheory of Continental Drift – all continents were once joined into one supercontinent called “Pangaea”, then broke apart and continue to move apart today
51Theories on Origin of Life ‘scientific’ theories based on the “Big Bang”Explosive, outward movement of mass, continuing todayNuclear fusion causes elements to form in stars
52Origin of Life On earth, a ‘primordial soup’ was formed Methane, ammonia, waterUrey and Miller – famous experiment – caused organic compounds to form when electricity (lightning) introduced to these compounds