1. Evolution and the Origin of Life

2. Origin of Life Need to make the monomers of the macromolecules Need to make the monomers of the macromolecules Need to make polymers of the monomers Need to make polymers of the monomers Need to form cells Need to form cells Need to be able to pass information from cell to cell Need to be able to pass information from cell to cell

3. 1. Making the first organic molecules Oparin and Haldane – believed organic molecules could be synthesized from inorganic molecules in the early atmosphere Oparin and Haldane – believed organic molecules could be synthesized from inorganic molecules in the early atmosphere Early atmosphere had no oxygen which usually scavenges electrons so different reactions can happen Early atmosphere had no oxygen which usually scavenges electrons so different reactions can happen Also need a lot of energy to form bonds like lightening and radiation from the sun with no ozone Also need a lot of energy to form bonds like lightening and radiation from the sun with no ozone Miller and Urey – took H2O, H2, CH4, NH3 although the atmosphere was probably more like CO, CO2, N2 (due to volcanic action) and hit it with electricity and were able to make some a.a., sugars, lipids, and nitrogen bases Miller and Urey – took H2O, H2, CH4, NH3 although the atmosphere was probably more like CO, CO2, N2 (due to volcanic action) and hit it with electricity and were able to make some a.a., sugars, lipids, and nitrogen bases Some believe that all organic cmpds were originally formed from inorganic molecules emitted from hyrdothermal vents in the ocean floor Some believe that all organic cmpds were originally formed from inorganic molecules emitted from hyrdothermal vents in the ocean floor Some believe they came from space Some believe they came from space

4. 2. Must form polymers In living things today, need enzymes to form polymers In living things today, need enzymes to form polymers If dilute monomers in water – no reactions If dilute monomers in water – no reactions If drop onto hot sand or rocks – can make proteins If drop onto hot sand or rocks – can make proteins Inorganic catalysts like Zn++ may have helped combine polymers Inorganic catalysts like Zn++ may have helped combine polymers May have stuck to clay which is charged and brought monomers close together May have stuck to clay which is charged and brought monomers close together

5. 3. Must form cells Formation of Protobionts – molecules aggregating forming a separate internal environment - Chemical reactions can take place within it and communicate with outside Formation of Protobionts – molecules aggregating forming a separate internal environment - Chemical reactions can take place within it and communicate with outside Proteinoids – throw some proteins together and form microspheres that are selectively permeable, can discharge voltage by ion flow like nerves,and can divide as add extra protein Proteinoids – throw some proteins together and form microspheres that are selectively permeable, can discharge voltage by ion flow like nerves,and can divide as add extra protein Liposomes – mix lipids together to form a lipid bilayer, able to engulf smaller liposomes and split Liposomes – mix lipids together to form a lipid bilayer, able to engulf smaller liposomes and split Coacervates – mix proteins, nucleic acids, sugars and cell assemble – if add enzymes – get taken into coacervate – they can then take in molecules and chemical react using the enzymes and put products out Coacervates – mix proteins, nucleic acids, sugars and cell assemble – if add enzymes – get taken into coacervate – they can then take in molecules and chemical react using the enzymes and put products out

6. 4. Must be able to pass instructions to make molecules or can never improve If want to pass info. on must be able to copy it If want to pass info. on must be able to copy it Can get RNA to copy itself in a tt/ can act as enyzmes Can get RNA to copy itself in a tt/ can act as enyzmes RNA can fold into many shapes thru b.p. RNA can fold into many shapes thru b.p. Some RNA may become more stable, copy faster – may be acted on by natural selection Some RNA may become more stable, copy faster – may be acted on by natural selection

7. Evolution – Chapter 22 Taxonomy – grouped things to better understand them and saw a pattern of relatedness Taxonomy – grouped things to better understand them and saw a pattern of relatedness Kingdom – Phylum – Class – Order – Family – Genus - Species Kingdom – Phylum – Class – Order – Family – Genus - Species Darwin saw descent with modification – all living things are descendents of a common ancestor and acquired modifications or adaptations that allowed them to survive in their environment Darwin saw descent with modification – all living things are descendents of a common ancestor and acquired modifications or adaptations that allowed them to survive in their environment

8. Darwin’s Finches

9. Darwin – Evolution – Explanation for Unity and Diversity Observation: Organisms have more babies than survive and resources can only support so much Observation: Organisms have more babies than survive and resources can only support so much Conclusion – strongest survive – only those that can get resources Conclusion – strongest survive – only those that can get resources Observation: There are variations in populations (due to mutation and genetic recombination) Observation: There are variations in populations (due to mutation and genetic recombination) Observation: Characteristics best suited to survive reproduce more and pass on those char. Observation: Characteristics best suited to survive reproduce more and pass on those char. Conclusion: Get a gradual change in population over time to those best suited Conclusion: Get a gradual change in population over time to those best suited

10. Darwin’s Evolution 1. Organisms are modified over time (Descent with modification) 2. Mechanism – Natural Selection Variation must already be present Variation must already be present Must be able to survive to reproduce to pass on traits to offspring Must be able to survive to reproduce to pass on traits to offspring Environment acts on inherited variations – Populations evolve not individuals Environment acts on inherited variations – Populations evolve not individuals

11. Evidence of Evolution Artificial Selection – by selecting certain natural variations – we’ve created whole new organisms Artificial Selection – by selecting certain natural variations – we’ve created whole new organisms Ex. Pigeons http://home.iprimus.com.au/spud1/pigeon_pictures.htm Ex. Pigeons http://home.iprimus.com.au/spud1/pigeon_pictures.htm Ex. Mustard Plant – forms kale, broccoli, cauliflower, cabbage, & brussel sprouts Ex. Mustard Plant – forms kale, broccoli, cauliflower, cabbage, & brussel sprouts Insecticide treatment of bugs Insecticide treatment of bugs Anti-biotic resistant bacteria Anti-biotic resistant bacteria Finches – beak size goes up and down due to wet vs. dry years Finches – beak size goes up and down due to wet vs. dry years Peppered Moths Peppered Moths Peppered Moth VideoDarwin's finches

14. Examples of Natural Selection insect mimicry

15. Evidence of Evolution Taxonomy – shows living things are all related – more similar in structure probably the more related Taxonomy – shows living things are all related – more similar in structure probably the more related Biogeography (where species are distributed) – Organisms living near one another are more like each other than organisms living in similar environments so came from a common ancestor and then adapted to the environment Biogeography (where species are distributed) – Organisms living near one another are more like each other than organisms living in similar environments so came from a common ancestor and then adapted to the environment Fossil Record – fossils show descendancy – relatedness matches age of fossils Fossil Record – fossils show descendancy – relatedness matches age of fossils Don’t find different vertebrate classes in the same age rock – appears to happen chronologically Don’t find different vertebrate classes in the same age rock – appears to happen chronologically Can find transitional fossils linking ancient and modern species Can find transitional fossils linking ancient and modern species

16. Evidence of Evolution Cont. Comparative Anatomy Comparative Anatomy Homologous Structures – shows relatedness vs. individual engineering Homologous Structures – shows relatedness vs. individual engineering Vestigial Organs – “left-overs” – no funtion in current times Vestigial Organs – “left-overs” – no funtion in current times Comparative Embryology – all vertebrates go through the same stages early on Comparative Embryology – all vertebrates go through the same stages early on Biochemistry/Molecular Biology – same DNA in all organisms – looks like modified copies of each other (mutations to make different proteins) Biochemistry/Molecular Biology – same DNA in all organisms – looks like modified copies of each other (mutations to make different proteins)

17. Homologous Structures

18. Homologous Structures show evolutionary relationships and should be used for classification Analogous structures do not show evolutionary relationship and are not used for classification

19. Comparative Embryology

20. Molecular Biology Comparisons

21. Hierarchy of Living Things

22. Evolution of Populations Chapter 23 Population – groups of same species all living together – may be geographically isolated but may mix some for reproduction but not as often as with own Population – groups of same species all living together – may be geographically isolated but may mix some for reproduction but not as often as with own Gene Pool – all the genes available in a population Gene Pool – all the genes available in a population Genetic Structure – frequencies of alleles and genotypes Genetic Structure – frequencies of alleles and genotypes Hardy-Weinberg – the genetic structure of a population will stay the same unless acted upon by outside factors (normal genetic recombination won’t change the overall frequencies of alleles or genotypes) Hardy-Weinberg – the genetic structure of a population will stay the same unless acted upon by outside factors (normal genetic recombination won’t change the overall frequencies of alleles or genotypes) This describes a population that is in equilibrium – non-evolving and stable This describes a population that is in equilibrium – non-evolving and stable

23. Hardy-Weinberg Equations If there are 2 alleles at a locus: p+q=1 If there are 2 alleles at a locus: p+q=1 p=frequency of 1 allele (usu. dominant) p=frequency of 1 allele (usu. dominant) q=frequency of other allele (recessive) q=frequency of other allele (recessive) Example with genes A and a: A+a=1 Example with genes A and a: A+a=1 Chance of getting the AA genotype = chance of getting A x chance of getting a 2 nd A or p 2 Chance of getting the AA genotype = chance of getting A x chance of getting a 2 nd A or p 2 Chance of getting the genotype aa = chance of getting a x chance of getting an a or q 2 Chance of getting the genotype aa = chance of getting a x chance of getting an a or q 2 Chance of getting Aa (2 ways) (Chance of getting A x chance of getting a) x 2 or 2pq Chance of getting Aa (2 ways) (Chance of getting A x chance of getting a) x 2 or 2pq

24. Hardy Weinberg All genotypes must = 100% All genotypes must = 100% Therefore: Therefore: P 2 + 2pq + q 2 = 1 P 2 + 2pq + q 2 = 1 P 2 = homozygous dominant P 2 = homozygous dominant q 2 = homozygous recessive 2pq = heterozygous

25. Hardy-Weinberg = A = a Allelic frequencies: A = 19/30 = 0.63 (63%) a = 11/30 =.37 (37%) p + q = 1.63 +.37 = 1 AA (.63) (.63) =.40 (40%) aa (.37) (.37) =.14 (14%) Aa (.37) (.63) 2 =.47 (47%) aA.40 +.47 +.14 = 1 P2 + 2pq + q2 = 1

26. Uses of Hardy-Weinberg Calculate the genotypic frequencies if know alleles or calculate allelic freq. if know genotypes Calculate the genotypic frequencies if know alleles or calculate allelic freq. if know genotypes Example #1: Example #1: 20/500 plants are white (aa) 320/500 are red (AA) 160/500 are pink (Aa) a: 40 alleles + 160 = 200/1000 = 20% or.2 A: 640 alleles + 160 = 800/1000 = 80% or.8 A + a = 1 Example # 2:  Example # 2: 13% of population is homozygous recessive q2 =.13 q =.36 p + q = 1 P =.64 2pq = Aa Or p2 + 2pq + q2 = 1.41 + x +.13 = 1 X =.46 (46% of population is carries the gene

27. Uses of Hardy-Weinberg Use equation to calculate what frequencies expected in next generation to see if population is changing Use equation to calculate what frequencies expected in next generation to see if population is changing If genetic structure is changing then the population is evolving If genetic structure is changing then the population is evolving Microevolution – change in genetic structure from one generation to the next. Microevolution – change in genetic structure from one generation to the next. May have microevolution of some loci and not others May have microevolution of some loci and not others

28. Hardy/Weinberg Practice Testing for H/W Equilibrium If a population is in H/W equilibrium, the genotypes will match H/W predictions given the allelic frequencies If a population is in H/W equilibrium, the genotypes will match H/W predictions given the allelic frequencies 4% of a population has sickle cell anemia (recessive trait) 4% of a population has sickle cell anemia (recessive trait) Calculate the frequencies for all 3 genotypes Calculate the frequencies for all 3 genotypes In this particular process 60% of the people are heterozygous and 36% do not have an allele for sickle cell. In this particular process 60% of the people are heterozygous and 36% do not have an allele for sickle cell. Draw a conclusion based on the expected and actual data – make a hypothesis why they are different. Draw a conclusion based on the expected and actual data – make a hypothesis why they are different.

29. The interlocking finger conundrum In a small isolated village of 2000 people, 1400 people’s left thumb ends up on top when they interlock their fingers. In a small isolated village of 2000 people, 1400 people’s left thumb ends up on top when they interlock their fingers. Calculate p and q for this population. Calculate p and q for this population. A few centuries later, this population has grown to 5000 people, and there are now 2000 left thumb on top people. Calculate p and q. A few centuries later, this population has grown to 5000 people, and there are now 2000 left thumb on top people. Calculate p and q. It is doubtful that there is any selection going on here. Propose other mechanisms for the allelic change. It is doubtful that there is any selection going on here. Propose other mechanisms for the allelic change.

30. Microevolution Deviation in the Hardy-Weinberg Equation (i.e. changes in an allelic frequency over generations) There are 4 things that can change the genetic structure of a population over time beside mutation There are 4 things that can change the genetic structure of a population over time beside mutation What are these mechanisms? Read about each one on pages 475-479. Each group member will read about one (non-random mating, genetic drift (founder and bottleneck), gene flow. You can also read about natural selection if you think it is necessary. Take turns explaining each one. What are these mechanisms? Read about each one on pages 475-479. Each group member will read about one (non-random mating, genetic drift (founder and bottleneck), gene flow. You can also read about natural selection if you think it is necessary. Take turns explaining each one.

31. Microevolution Continued You will illustrate each of these mechanisms of allelic change based on a story about a community of angry birds. You will illustrate each of these mechanisms of allelic change based on a story about a community of angry birds. Mutations are the underlying factor of the other 4 mechanisms of allelic change so we won’t illustrate mutation by itself. Mutations are the underlying factor of the other 4 mechanisms of allelic change so we won’t illustrate mutation by itself. Now lets go to our story Now lets go to our story Now lets go to our story Now lets go to our story

32. It’s Now 2075 Pick one gene: Eyebrow geneallele 1: V-shaped allele 2: sunglass like Head Featherallele 1: rounded gene allele 2: pointed gene allele 2: pointed Eye geneallele 1: regular allele 2: glowing What is the Red Angry Bird Population Like Now? For the gene you chose and the mechanism you are assigned, make up a plausible and creative story to explain the mechanism incorporating environmental factors and correct terminology

34. What Causes Deviation From Hardy –Weinberg? Genetic drift – changes due to chance – only improvement would be luck Genetic drift – changes due to chance – only improvement would be luck Larger populations more closely reflects frequency of past generations – smaller populations will tend to change by chance Larger populations more closely reflects frequency of past generations – smaller populations will tend to change by chance Factors that increase genetic drift: Factors that increase genetic drift: Bottleneck – disasters kill off a bunch – remaining small population isn’t representative of original population – drift more Bottleneck – disasters kill off a bunch – remaining small population isn’t representative of original population – drift more Founder – a small group colonizes an island – small group will tend to not be representative of whole group Founder – a small group colonizes an island – small group will tend to not be representative of whole group

35. Deviations from Hardy-Weinberg Gene Flow – genetic exchange – interaction of one pop. with another Gene Flow – genetic exchange – interaction of one pop. with another May be due to migration, wind, etc. May be due to migration, wind, etc. Ex. Other pop. has more aa due to local environment so increases freq. in other population Ex. Other pop. has more aa due to local environment so increases freq. in other population Mutations– change in one allele to another – must be in gamete Mutations– change in one allele to another – must be in gamete Infrequent and usually causes small variation so by itself – doesn’t change pop. much Infrequent and usually causes small variation so by itself – doesn’t change pop. much Provides variation for selection Provides variation for selection (Don’t forget genetic recombination) (Don’t forget genetic recombination)

36. Deviations from Hardy-Weinberg Non-random Mating – in-breeding, self- fertilization, only mating in close proximity, mating based on selective characteristics Non-random Mating – in-breeding, self- fertilization, only mating in close proximity, mating based on selective characteristics All usually increase homozygosity All usually increase homozygosity ***Natural Selection – Hardy-Weinberg assumes that all genotypes have the same ability to survive and reproduce which isn’t true – this is probably the major factor controlling evolution ***Natural Selection – Hardy-Weinberg assumes that all genotypes have the same ability to survive and reproduce which isn’t true – this is probably the major factor controlling evolution

37. Evolution – Deviation from Hardy- Weinberg Anyone of the previous things can cause evolution but natural selection acts on all changes to determine what allele has the highest concentration over time so with natural selection a disproportionate # of alleles are passed to the next generation Anyone of the previous things can cause evolution but natural selection acts on all changes to determine what allele has the highest concentration over time so with natural selection a disproportionate # of alleles are passed to the next generation Natural Selection is the only adaptive mechanism Natural Selection is the only adaptive mechanism

38. Evolution: Needs variation Variation must be present though for anything to change therefore mutation and recombination must be at the root Variation must be present though for anything to change therefore mutation and recombination must be at the root Variations must be heritable or can’t effect evolution Variations must be heritable or can’t effect evolution However, many mutations wont’ make a difference due to: However, many mutations wont’ make a difference due to: Reduncancy of the genetic code Reduncancy of the genetic code Mutation in non-coding regions Mutation in non-coding regions Mutations in genes not expressed Mutations in genes not expressed Mutations not in germ cells Mutations not in germ cells Changes that aren’t adaptive Changes that aren’t adaptive

39. Measuring Genetic Variation Polymorphisms How many loci aren’t fixed How many loci aren’t fixed Average # of loci that are heterozygous Average # of loci that are heterozygous Nucleotide diversity - # of nucleotides different – compare DNA between 2 individuals and pool data from many comparisions Nucleotide diversity - # of nucleotides different – compare DNA between 2 individuals and pool data from many comparisions Our genetic diversity among humans is 14% by gene or loci, but our nucleotide diversity is 0.1% so with 6 x 10 9 b.p – about 6 x 10 6 are different or out of every 1000 b.p. – 999 are the same

40. Once have variation – Evolution need selective pressure Selective Pressure between populations is due to geographic variation (different local conditions) – acts upon previous mutations to change genetic structure and may create subpopulations or clines Selective Pressure between populations is due to geographic variation (different local conditions) – acts upon previous mutations to change genetic structure and may create subpopulations or clines Selective Pressure within populations is due to competition for food, homes, & mates, environmental conditions (weather), Selective Pressure within populations is due to competition for food, homes, & mates, environmental conditions (weather),

41. Types of Natural Selection Stabilizing – select against the extremes (human birth weight) Stabilizing – select against the extremes (human birth weight) Directional – during environmental changes or migration, shifts to a new phenotype (bird beaks, scale sucking fish) Directional – during environmental changes or migration, shifts to a new phenotype (bird beaks, scale sucking fish) Diversifying – selects for both extremes (finches in Africa – selects against medium beak that isn’t good at cracking either food sourced) Diversifying – selects for both extremes (finches in Africa – selects against medium beak that isn’t good at cracking either food sourced) Separate Selection based on sex – leads to sexual dimorphism (selected by Separate Selection based on sex – leads to sexual dimorphism (selected by pressure to mate) pressure to mate)

42. Natural Selection Should Lead Away from Diversity so… Why do populations remain diverse? Diploidy – hides variation from selection – heterozygous conditions keeps alleles in population since recessive alleles can’t be acted on by selection when coupled with a dominant one (protects alleles not suited to environment) Diploidy – hides variation from selection – heterozygous conditions keeps alleles in population since recessive alleles can’t be acted on by selection when coupled with a dominant one (protects alleles not suited to environment) Balanced Polymorphisms Balanced Polymorphisms 2 variations may work the best 2 variations may work the best Heterozygous advantage – Aa works best Heterozygous advantage – Aa works best Alternating selective pressure, diversitying selective pressures Alternating selective pressure, diversitying selective pressures Neutral Effects – variations make no difference (not adaptive) but may become adaptive later Neutral Effects – variations make no difference (not adaptive) but may become adaptive later Not alter reproductive fitness (Huntingdon’s) Not alter reproductive fitness (Huntingdon’s)

43. Why Populations Remain Diverse Continued Mutation – the same mutation may keep arising like in neurofibromatosis Continued Mutation – the same mutation may keep arising like in neurofibromatosis 1/4000 spontaneous gamete mutations 1/4000 spontaneous gamete mutations Gene Flow – gene may not be deleterious in a nearby population (ex. Sickle cell allele) Gene Flow – gene may not be deleterious in a nearby population (ex. Sickle cell allele) Natural Selection may not have had time to remove the allele yet – may have not been deleterious previously and is now being selected against but not yet gone (ex. Cystic fibrosis in Caucasians – allele gives resistance to cholera) Natural Selection may not have had time to remove the allele yet – may have not been deleterious previously and is now being selected against but not yet gone (ex. Cystic fibrosis in Caucasians – allele gives resistance to cholera)

44. Speciation New species appear in rock – where did they come from? How did new species form? New species appear in rock – where did they come from? How did new species form? Species – can interbreed and produce fertile offspring under natural conditions – physically and biochemically distinct – not just mixtures Species – can interbreed and produce fertile offspring under natural conditions – physically and biochemically distinct – not just mixtures Anagenesis – one species transforms into another Anagenesis – one species transforms into another Cladogenesis – an ancestor produces one or more different variations and all exist simaltaneously (increases the # of species) Cladogenesis – an ancestor produces one or more different variations and all exist simaltaneously (increases the # of species)

45. Why species remain distinct Pre-zygotic Barriers Habitat Isolation – live in different areas Habitat Isolation – live in different areas Behavioral Isolation – mating rituals, firefly lighting patterns Behavioral Isolation – mating rituals, firefly lighting patterns Temporal Isolation – different mating times (seasonal), different times of flowering, nocturnal vs. day Temporal Isolation – different mating times (seasonal), different times of flowering, nocturnal vs. day Mechanical Isolation – physically impossible to mate Mechanical Isolation – physically impossible to mate Gametic Isolation – gametes can’t match up Gametic Isolation – gametes can’t match up

46. Why Species remain distinct Post-zygotic Barriers Poor Hybrid viability – embryos die Poor Hybrid viability – embryos die Poor Hybrid fertility – offspring can’t reproduce Poor Hybrid fertility – offspring can’t reproduce Hybrid Breakdown – make a weak or sterile second generation Hybrid Breakdown – make a weak or sterile second generation

47. Origin of New Species – members must become separated so acted on differently by natural selection Allopatric Speciation – a population becomes separated by a physical barrier – have different selective pressures after separation Allopatric Speciation – a population becomes separated by a physical barrier – have different selective pressures after separation Examples Examples migration to different islands migration to different islands New mountain separates them New mountain separates them Lake dries up to multiple little ponds Lake dries up to multiple little ponds

48. Origin of New Species Cont. Sympatric Speciation – a population becomes reproductively isolated but still lives with the parent population Sympatric Speciation – a population becomes reproductively isolated but still lives with the parent population Examples Examples Plant that becomes polyploid can only reproduce with other polyploid plants and not others of its kind (25- 50% of plants – oats, cotton, potatoes, tobacco) Plant that becomes polyploid can only reproduce with other polyploid plants and not others of its kind (25- 50% of plants – oats, cotton, potatoes, tobacco) Animals – genetic change causes a difference that keeps them from mating – may eat a different food source and don’t mate with others eating a different food source. May become adapted to live on a certain plant and never meet the group living on a different plant Animals – genetic change causes a difference that keeps them from mating – may eat a different food source and don’t mate with others eating a different food source. May become adapted to live on a certain plant and never meet the group living on a different plant Sex Selection may play a role (females only mate with males with a certain trait) Sex Selection may play a role (females only mate with males with a certain trait)

49. Why evolution takes places once a population becomes separated Organisms on the edge are usually different anyway Organisms on the edge are usually different anyway Founder effect (small group leaving may not be representative of whole) Founder effect (small group leaving may not be representative of whole) Genetic Drift Genetic Drift Neutral mutations may become fixed without selective pressures due to small population size Neutral mutations may become fixed without selective pressures due to small population size Different selective pressures Different selective pressures Therefore: Microevolution over time slowly changes each population

50. This is called adaptive divergence – adapt to environment which causes a 2ndary reproductive isolation This is called adaptive divergence – adapt to environment which causes a 2ndary reproductive isolation Sometimes there are adaptive “peaks” – may have several forms that are optimized for success (more than 1 selective pressure) and chance may cause to a change in form or environment may slowly change causing a shift from 1 peak to another Sometimes there are adaptive “peaks” – may have several forms that are optimized for success (more than 1 selective pressure) and chance may cause to a change in form or environment may slowly change causing a shift from 1 peak to another

51. What happens if separated species come back together? May interbreed and become a mix May interbreed and become a mix May stay separate due to reproductive barriers May stay separate due to reproductive barriers Hybrid Zone – only interbreed where overlap and other parts of population remain separate Hybrid Zone – only interbreed where overlap and other parts of population remain separate If there aren’t true reproductive barriers – still a separate species? If there aren’t true reproductive barriers – still a separate species?

52. Macroevolution substantial change in organisms substantial change in organisms Origin of taxonmic groups higher than species Origin of taxonmic groups higher than species Origin of new phyla, classes, orders, families Origin of new phyla, classes, orders, families Is it due to the cumulative product of microevolution or some big event or…???? Is it due to the cumulative product of microevolution or some big event or…???? The appearance of flowering plants seems to be all at once????? The appearance of flowering plants seems to be all at once????? The appearance of mammals seems to be all at once????? The appearance of mammals seems to be all at once?????

53. Punctuated Equilibrium Big changes (episodes of speciation) followed by slow gradual change (if optimized for environment – shouldn’t be a lot of change due to selection unless large change in selection pressures) Big changes (episodes of speciation) followed by slow gradual change (if optimized for environment – shouldn’t be a lot of change due to selection unless large change in selection pressures) Due to quick geographic separation and genetic drift Due to quick geographic separation and genetic drift Due to sudden genome changes Due to sudden genome changes Changes may not be shown in fossils Changes may not be shown in fossils

54. Fossils Organic parts of dead organisms decay – rest of inorganic material like shells etc. remain in sedimentary rock Organic parts of dead organisms decay – rest of inorganic material like shells etc. remain in sedimentary rock Minerals may replace organic part of dead organisms and harden it which preserves it (petrification) Minerals may replace organic part of dead organisms and harden it which preserves it (petrification) May leave a mold (imprint) in rock that is later hardened by minerals (makes a cast) May be footprints, burrows, things that leave hints of behavior May leave a mold (imprint) in rock that is later hardened by minerals (makes a cast) May be footprints, burrows, things that leave hints of behavior Whole organism may be preserved in the absence of decomposers like in amber, ice, acid bogs, dry areas Whole organism may be preserved in the absence of decomposers like in amber, ice, acid bogs, dry areas Dead organism pressed between rocks – may preserve even organic parts like cells – sometimes pollen is preserved because it is in a hard case Dead organism pressed between rocks – may preserve even organic parts like cells – sometimes pollen is preserved because it is in a hard case

55. Fossils continued Most fossils would be organisms that lasted a long time, were abundant, had shells or hard skeletons Most fossils would be organisms that lasted a long time, were abundant, had shells or hard skeletons Any fossils found are by luck Any fossils found are by luck Had to wash with sediments Had to wash with sediments Rock had to last untouched Rock had to last untouched Had to be exposed Had to be exposed Had to be found Had to be found

56. Dating Fossils Sedimentation isn’t uniform – rocks are found in layers or strata – the further down “the stack”, the older it is (only relative age) Sedimentation isn’t uniform – rocks are found in layers or strata – the further down “the stack”, the older it is (only relative age) Correlate age of strata from 1 place to another by similar strata with same fossils Correlate age of strata from 1 place to another by similar strata with same fossils Based on times of great change between strata, mass extinction followed by an explosion in adaptive radiation divides Earth’s history into 4 eras: Precambrian, Paleozoic, Mesozoic, Cenozoic Based on times of great change between strata, mass extinction followed by an explosion in adaptive radiation divides Earth’s history into 4 eras: Precambrian, Paleozoic, Mesozoic, Cenozoic

57. Radiometric Dating Use ½ life of radioactive elements Use ½ life of radioactive elements Time it takes for 50% to decay Time it takes for 50% to decay Know ratio of C-14/C-12 in living things Know ratio of C-14/C-12 in living things Measure how much relative C-14/C12 now and can tell how many ½ lives Measure how much relative C-14/C12 now and can tell how many ½ lives Example: Fossil has ¼ C-14/C-12 as living organism = 2 ½ lives – to get age – take ½ life of C-14 x 2. Example: Fossil has ¼ C-14/C-12 as living organism = 2 ½ lives – to get age – take ½ life of C-14 x 2.

58. Dating Questions How do we know that ½ life is a steady decay How do we know that ½ life is a steady decay How do we know it isn’t altered by climate How do we know it isn’t altered by climate How do we know fossil had same ratio as living organisms today How do we know fossil had same ratio as living organisms today How accurate is the measure of C-14/C-12 How accurate is the measure of C-14/C-12 Error is 10% - how do you measure error? Error is 10% - how do you measure error?

59. Mechanisms of Macroevolution Pre-adaptation – structure is adapted for 1 thing and later used for another function (gradual change in existing structure leads to a new function) Pre-adaptation – structure is adapted for 1 thing and later used for another function (gradual change in existing structure leads to a new function) Example – lattice-like bones of birds – some dinosaurs had it but must have had another function Example – lattice-like bones of birds – some dinosaurs had it but must have had another function Changes in developmental genes Changes in developmental genes Heterchrony – changes in developmental timing or rate Heterchrony – changes in developmental timing or rate Homeosis – alteration in placement of body parts Homeosis – alteration in placement of body parts

60. Developmental Gene Changes Examples: Examples: Allometric growth – differences in relative rate of growth of a certain part during development like skull bones and brains Allometric growth – differences in relative rate of growth of a certain part during development like skull bones and brains Padeomorphosis – change in developmental timing – adult keeps characteristics of juvenile form of ancestor Padeomorphosis – change in developmental timing – adult keeps characteristics of juvenile form of ancestor

61. Changes in genes that control rate of growth or developmental timing can make big changes

62. Mechanisms of Macroevol. Cont. Species Selection – things evolve into other species or may branch into other species and only strongest species survives Species Selection – things evolve into other species or may branch into other species and only strongest species survives Mass Extinction – due to huge geographical changes (climate, destruction of habitats) – leaves it open for species to fill new places “adaptive radiation” Mass Extinction – due to huge geographical changes (climate, destruction of habitats) – leaves it open for species to fill new places “adaptive radiation”

63. Examples: Continental Drift End of Paleozoic – Pangaea formed End of Paleozoic – Pangaea formed Permian extinction – species now in competition with things never saw before Permian extinction – species now in competition with things never saw before Less shore-line, extreme volcanism with great temperature effects Less shore-line, extreme volcanism with great temperature effects Mass extinction (90% species gone) – chance for new species Mass extinction (90% species gone) – chance for new species Early Mesozoic – Pangaea breaks up – geographical isolation Early Mesozoic – Pangaea breaks up – geographical isolation Formation of mountains, new islands, earthquakes Formation of mountains, new islands, earthquakes

64. Mass Extinction causing Macroevolution Cont. Cretaceous Extinction – possible asteroid hit – large layer of rock made of sediments found in asteroids but not on earth (large craters present) Cretaceous Extinction – possible asteroid hit – large layer of rock made of sediments found in asteroids but not on earth (large craters present) loss of more than 50% of marine species loss of more than 50% of marine species Cooler tempatures, shallow seas receded Cooler tempatures, shallow seas receded With any of these times of mass extinction – surviving species are a stock for new radiations, fossils do show periods of mass extinction and adaptive radiations, organisms filling the void left by others

65. Mechanisms of Macroevolution Cont. Accumulation of Microevolution not preserved in fossil record or intermediates not found due to small numbers Accumulation of Microevolution not preserved in fossil record or intermediates not found due to small numbers

66. Cladograms Diagrams that show probable relationships between the taxa, sequence of origin, common ancestors, shared characteristics

67. Systematics – study of biodiversity in an evolutionary context Want to decide an organisms taxa based on evolutionary relationships Want to decide an organisms taxa based on evolutionary relationships How do scientists decide? Comparative Anatomy Comparative Anatomy Analogous structures – similar due to like environments, built from different structures (ex. Wings or birds and insects) Analogous structures – similar due to like environments, built from different structures (ex. Wings or birds and insects) Homologous structures – similar due to common structure and therefore common ancestry (ex. Wing of bat, whale fin, arm of human, paw of dog) Homologous structures – similar due to common structure and therefore common ancestry (ex. Wing of bat, whale fin, arm of human, paw of dog) Should only use homologous structures for classificaiton Should only use homologous structures for classificaiton Problem with comparative anatomy – like structures not necessarily from common ancestor – may be due to convergent evolution – shaped by same environmental factors Problem with comparative anatomy – like structures not necessarily from common ancestor – may be due to convergent evolution – shaped by same environmental factors

68. Systematics – classifying cont. Proteins – closer the aa sequence – probably from a closer common ancestor Proteins – closer the aa sequence – probably from a closer common ancestor DNA – closer nucleotides sequences – more related (dolphins are closer to bats than sharks) DNA – closer nucleotides sequences – more related (dolphins are closer to bats than sharks) Can extract DNA from fossils Can extract DNA from fossils DNA-DNA Hybridization – see overall similarity of genomes by checking amountof H-bonding between 2 ss DNA’s from 2 different organisms DNA-DNA Hybridization – see overall similarity of genomes by checking amountof H-bonding between 2 ss DNA’s from 2 different organisms Restriction Mapping Restriction Mapping DNA sequencing – compare rRNA’s to look for branching since seems to have changed the slowest DNA sequencing – compare rRNA’s to look for branching since seems to have changed the slowest Molecular clocks – if rate of DNA change is constant and can calculate when diverged using fossils dating – can calculate the rate of DNA change/time Molecular clocks – if rate of DNA change is constant and can calculate when diverged using fossils dating – can calculate the rate of DNA change/time

69. Summary of Macroevolution May be due to rapid changes: May be due to rapid changes: Mass separations Mass separations Rapidly changing environments Rapidly changing environments Chromosomal or developing genes mutating Chromosomal or developing genes mutating Mutations acted upon by huge genetic drift and selection Mutations acted upon by huge genetic drift and selection Mass extinctions causing adaptive radiations Mass extinctions causing adaptive radiations

70. Remaining Questions about Macroevolution Could it really be compounded microevolution? What is gradual vs. quick? Is the fossil record complete? Do different mechanisms work at different levels?