BIOL-112 September 2, 2021CHAPTER 18Homologous: same anatomical structure (internal anatomy) evolving into different lineages- ex: humerus, ulna, radius, metacarpal, phalangesAnalogous: same trait that is inherited but different structure- ex: wings - - - convergent evolution and analogous traits go hand in hand- same trait different functions ex: not all birds can flyVestigial: if you look at the evolution of the structure it is diminishing in the functionality- ex: pelvic bones in whales - - they lose functionality but it has not lost functionNature tends to evolve towards an increase in surface level- ex: camouflage We live on an unstable rock with a lot of unstable geneticsIf the environment changes, selection pressures are going to change in order to adaptPrior to industrial revolution, plants had a certain trait and after the industrial revolution they’ve been lost Evolution: differences in genetics, changes in environment, and dominoes start to fallIf the trait is selected, the certain species stays in the populationFossils are a big deal - western Africa has the same fossils in south America - they originated in the same placePlates moving leads to changes in weather patterns changes to changes in the natural world- plates shift = more warm shallow seas- oxygen levels go upWhen elements of science gets mixed with popular culture, things get mixed up** Molecular BiologyThomas KuhnParadigm shifting: in science, we are not afraid to change our mind but the paradigm does shiftTaxonomy and Cladistics: they are constantly changing- women and men are constantly surveying genomes**Misconceptions of Evolution- evolution is just theory- individuals evolve- teleological- evolutions explains the origin of life- organisms evolved on purpose- nature is NOT teleological - tele = last- teleological means “to NOT operate with a plan”**Speciation – Formation of New Species- Ernst Mayr- biological species: a group that can interbreed and do interbreed; they have viable offspring and choose NOT to interbreed with other groups - hybrid: a cross between two species- gene pool: a collection of all variants of genes in a species**Speciation- allo = “other”- sym = “together”- patric = “area or space”* how species come to be*- long distances are geographical divides- “how do these species come to be?”Allopatric speciation – involves geographic isolationSympatric speciation – occurs in the same geographical area- same area but we start to see isolation from each other despite the fact that they are still technically there together - chromosomal errors in cell division – MUTATION- different starting genetics different environmental pressures- different genetics that come to be over timeBacteria mutate antibiotic resistance all the time**Reproductive Isolation - - EXAM 1 INFORMATION AND FINAL EXAMReproductive IsolationHybrids – TWO TYPES1. Certain hybrids that do well2. Certain hybrids that don’t exist for maybe a couple generations- hybrids are either sterile or through later generation fail to exist* how species are maintained* Prezygotic Barriers: they have the same traits but want nothing to do with them- impeding different species from attempting to mateHabitat isolation: live in different placesTemporal isolation: temporal = time- they are reproductively viable at different times of the year Behavioral isolation: courtship rituals ** Anthropocentric **Mechanical isolation: morph = form- anatomically they are unable to perform well in order to mateGametic isolation: species-specific bindin protein has to fit specifically to fit the receptor like a “key in a lock” in order to mate - the protein has to fit the receptor on the egg (zona-pellusta) ** Postzygotic Barriers: maintain species- hybrids do not do well when these 3 are in playReduced hybrids viabilityExtinction: 99% of all living things in this world have become extinct ** Concept 24.2Speciation can occur in basically 2 ways:- allopatric speciation- sympatric speciation**VARK learning styles survey**** Allopatric SpeciationAllopatric speciation: gene flow is interrupted or reduced when a population is divided in geographically isolated subpopulations- Long distances- the greater the divide = the greater the degree that speciation will take place over the years** Mosquito Fish Slide- under high predation vs under low predationFundamental Element of Evolution: just because a trait is there doesn’t mean that it has this “fabulous” function**Sympatric Speciation- polyploidy- poly = many- ploidy = chromosome #- autopolyploid- made my humans- ex: bananas auto = “self”replicates its own DNA- allopolyploid- allo = “other”- simpolyploid** Allopatric Speciation- dispersal = when a few members of a species move to a new geographical area - aka “founder effect”- vicariance = when a natural situation (barrier) arises to physically divide organisms- not seen as much with great geographical distances ** Adaptive Radiation: when a founder species in a short period of time becomes a new species that can be tracked back to one ancestral species **Sympatric Speciation- when you count chromosomes count centromeres - nondisjunction: an unequal division of the DNA during miotic goings on - monosomies will be at the 23rd spot in humans but you’ll see that an nothing else - autopolyploidy** Reproductive Isolation- Presygotic- PostzygoticAllo and sym = forming speciesPre and post = maintains species Gametic barrier - - “species specific bindin proteins” - coevolution**Reconnection - - these are the hybrids that do well- hybrid fusion: when the hybrid out competes both parent A and B - reinforcement: parental species just kind of move away- stability: both the parents and hybrids does well - - started out with two and ended up with 3Postzygotic example = sterile mule ** Rates of Speciation- gradual speciation: species forming over time - punctuated equilibrium: where there is all of a sudden a radical departure based on a rapid change in environment- steven j goule - - the individual from Harvard- he did his research on islands -> islands are good biological laboratories ** Rates of Speciation- speciation happens more often on islandsCHAPTER 10 September 7, 2021What is Genetic Drift?- In a population can lead to the elimination of an allele from a population by chance- The smaller the population the greater effects of genetic drift (randomness)Anthropocentric: seeing the entire natural as being
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