EVOLUTION Change in a species through time

How Do Living Things Change  Variation ______________________  During DNA replication  During transcription/ translation _______________________  Getting different traits from 2 parents versus 1. CAN YOU CHANGE YOUR DNA (like right now, with no super secret laser)?

How did life START on Earth?  Evolution does not explain creation of life just that life changes…so how did life start?  Several hypothesis’ Creationism Extra-terrestrialism Heterotroph hypothesis

 Life began about 3.5 million years ago  At that time there was no oxygen, just a mixture of hydrogen, water, ammonia, and methane…with a flash of lightning, the first living organism was formed. It was an _______________________.  Still no oxygen, a __________ formed _________________ AUTOTROPH –

 Since we know that autotrophs make Oxygen, a mutation that would allow an organism to utilize that oxygen would be beneficial  Along came ____________ organisms

Evidence for Evolution  How do we know organisms lived long ago (like millions of years ago) and how do we know what they looked like?  Inorganic Evidence ______________  Sedimentary rock  Carbon Dating _______________

More evidence for evolution  Organic evidence _______________– same structure different function _______________ = different structures same function _______________– organs that no longer have a function (like an appendix) Pelvis of a whale

Organic Evidence  Comparative _______________ – comparing the developing fetus’ of several species  Comparative _______________ – comparing the tissues of several species  Comparative _______________ – comparing DNA, proteins, etc, of several species

Theories of Evolution  Lamark – First to try to account for making sense of why things look similar… Theory of need Theory of use and disuse Inheritance of Acquired Characteristics  Weismann – “The mice man” Disproved Lamark

Darwin  Father of evolution – went to school to be a doctor. Hated it! Went to school to become a priest. Went on the ship the HMS Beagle in 1831 to the Galapagos Islands. Collected data from around the Islands and wanted to make sense of how they looked so similar to the main land animals but yet so different.  In 1859 published his theory of Natural Selection

Natural Selection  The finches were one of the main species that he looked at and noticed these differences.  There are 5 parts to his theory of evolution: 1. _______________ – (like seen here) – differences within a population

Parts to evolution 2. _______________ – making more babies then can survive. 3. _______________ – Because there are too many offspring, they must fight for survival. 4. _______________– With the competition and variation within the species, those with favorable adaptations will survive! 5. _______________ - Those that best survive will pass on those traits to their offspring

Types of natural selection  _______________– eliminates extreme individuals (rather then tall or short plants you get medium plants)  _______________– selection against one extreme – widow bird selecting for long tails  _______________– eliminates intermediate individuals - tall and short dandelions

 PLEASE NOTE – THE ENVIRONMENT IS THE SELECTING AGENT!!!!!!  If the organisms/ species has the GENE then it will survive.  If the environment CHANGES – the traits favored also CHANGES

Genetic Basis for Evolution  Darwin didn’t know about DNA – first came Mendel to explain genetics (genotype and phenotype) then Watson and Crick in the 1950’s with DNA…  With Mendel we could explain why the frequency of the alleles for certain traits increase within a gene pool while others decreased.

Hardy Weinberg Equilibrium  A large sexually reproducing population will have a stable allelic frequency given the following five conditions Large population No immigration or emigration Random mating Random reproductive success No mutation

Hardy Weinberg equation  Please see your notes from Genetics – (population genetics) for equation  Remember we used a punnett square to determine frequencies.  WHY would this equation help in evolution?

Evolution by chance  Genetic Drift – evolution in the absence of natural selection ______________ population size is drastically reduced by some event. For example, you have 50 pennies and 50 nickels in your pocket, you lose ALL BUT 4, you could have any combination of pennies and nickels… ______________ – a small number of individuals populate a new area _______________ – must occur in a gamete to be passed on – to dramatically effect a gene pool must be combined with one of the above

Isolation  A physical separation of one population from another so that interbreeding can not occur Geographic Isolation – physical barriers like mountains/ oceans Physiological barriers –  Premating – differences in species recognition/ mating calls etc  Post mating – differences in genetalia, sperm can’t fuse with ovum, young may survive but are sterile (mule)

Pace of evolution  ___________ – over time, accumulations of small differences makes two population into two different species  _________ __________ – long period of no change followed by a quick dramatic change

Evolutionary/ phylogenetic trees  These allow us to see common ancestors and evolutionary relationships **Based on DNA