2 PhylogenyThe history of the evolution of a group of organisms
3 Adaptation – 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
4 Theories of Evolution Lamarck Law of Use and Disuse: organisms can change their body features during their lifetimes to satisfy their needs.
5 Theories of Evolution Lamarck 2. Acquired characteristics are inherited:Those characteristics changed during the lifetime of an individual can be passed on to offspring
6 Ex) Giraffes are able stretch their necks to reach leaves and this trait is passed on to their offspring.
7 Darwin Job was a ‘naturalist’ – recorded and sampled new species Voyaged on the Beagle to the Galapagos Islands
8 Darwin observed many species Ex) Finches had adapted to eat blood, use sticks in holes, drill holes
9 Darwin He also noticed curious species: Iguanas that ate algae from oceanFlightless cormorants
10 DarwinAssumed that all species evolved from a common ancestor, probably from the mainlandEx) armadillo evolved from glyptodont
11 Darwinproposed that evolution occurred by natural selection and published his theory in 1859
12 Another scientist Alfred Wallace had similar ideas
13 Theory of Natural Selection Overproduction – more offspring produced than surviveStruggle for existence – organisms compete within and between species
14 Theory of Natural Selection 3) Variation – exists in any population and the variations are passed on to the next generation (genetic differences)
15 Theory 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)
16 Theory 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.
17 Key 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
18 Giraffes 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!
19 How do new traits appear? MutationSexual reproduction produces new combinations
32 ConvergenceVery different species may also develop similar adaptations due to similar needs in their environmentEg. Squid and human eye
33 Adaptive Radiation Or divergence Similar species become quite different due to differing environmental needs
34 Two 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
47 Evidence for Evolution Comparative BiochemistryRecent advances in DNA profiling and protein sequencing has allowed us to study the similarities in common molecules
48 PrimateNo. Of Amino Acids Different From HumansChimpanzeeIdenticalGorilla1Gibbon3Rhesus Monkey8Squirrel Monkey9
49 Evidence 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
51 Theories 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
52 Origin 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