Macro evolution

Question 1

Change in perspective

Answer 1

Move to How does evolution pay out on grand time scales
- Not within popultion
- How do evolutionary porcesses scale up to long term change we see in fossil records

***Taking our understanding of mechansims of evolution to see if they explain patterns of larger change through time

Question 2

Evolution as an on-going process

Answer 2

Evolution is an ongoing process –> see change in allele frequencey from one generation to next BUT now what happens when scale up 3 billion years

We are going to turn to how the mechansims of evolution have played out in the long run
- Is there meaningful distiction between micro and macro evolution

Question 3

Micro vs. macro evolution

Answer 3

Micro –> evolution process within popultion

Macro –> patterns of change above species level

Micro –> macro – is this just allele frequencey change – can we look based on popultion genetics or do other factors come into play

Question 4

Speciation + micro/macro evolution

Answer 4

Interface between micro and macro evolution (during speciation within species variation is converted to variation between species by our basic microevolutionary forces) – in this sense macroevolutionary change is just scaled up microevolutionary change BUT the vast time scale may add some important factors that are worth considering
- If Micro evolution is population genetic changes within populations and macroevolution involves patterns of change above the species level then speciation is the link between the two

Link = derived from mechanisms of evolution point of view – maybe can just extend mechanisms trhough time

Question 5

Macroevolution

Answer 5

Large evolutionary change, usually in morphology, typically refers to the evolution of differences among populations that would warrant their placement in different higher-level taxa (beyond species)

Question 6

Questions in unit

Answer 6

1. Do we see trends NS favoring phenotypic change through time? Are certain directions of phenotypic change favored in the long run?
   
   • Some level of predictability in process
   • How might researchers see if reason is because SN is favoring rather than passive?
2. What are the patterns of biological diversity through time? Consider both that diversity as a whole and the composition of that diversity by different major clades and their change through time.
   
   • Increase or decrease diversity
   • Process to drive turnover in biodiveristy

Question 7

Determine trends of evolutionary change

Answer 7

Can extend gould’s wall of complexity –> complexity increases even if NS does not tend to favor complexity
- Just need limit on one end –> since have limit = distribution only goes one way –> means the average only goes one way because have limit

Before = discussed with complexity BUT we can apply to many phenotypes

Example - can apply to morphology or chemical reactions that are passive or NS favoring outcomes

Question 8

Application of Goulds left wall

Answer 8

Example – body size

Apparent direction bias through time = Cope’s Rule –> body size increases through evolutionary time (larger organisms derived from smaller) = increase body size favored by NS

2 Hypothesis for increase in body size through time:
1. Conform to cope –> was small and have consistent favor in increase in body size

2, Gould –> have minimum threshold to how small –> pasisve chnage but in end increas ein trait value

Charts:
Left = NS favored
Right = Passive –> mimimum thrshold for how small can be that set wall to allow passove provess to increase trait value through time

Question 9

Directions vs. Biased changes

Answer 9

Whether apparent directional patterns in evolution are the result of biases in directional selection or passive processes with constraint can be difficult to parse apart
- Try to parse out if apparent trend is driven by NS or passive process

Question 10

Cope’s rule

Answer 10

Observation that body size appears to increase in lineages through time

Question 11

2 hypothesis for change in body size predictions

Answer 11

These two hypotheses make specific predictions for how phenotypic change plays out:

1. In driven trends both ends of the distribution change in the same direction through time (in passive trends the minimum remain unaltered) vs. passive where only one end of the distubution changes through time

Question 12

First prediction about body size

Answer 12

In driven trends both ends of the distribution change in the same direction through time (in passive trends the minimum remain unaltered) vs. passive where only one end of the distribution changes through time

Left image = passive – can’t be smaller = through time trait value increases – Does so in passive manner
- Increase maximum
- Mean Trait value increase through time because max changes but the minimum stays the same

Right = Increase maximum and minimum through time –> shift on both sides = NS favoring dorection of change
- Entire distribution moves –> not only stretch ax – change both ends

Question 13

Scaling Mechanisms of evolution

Answer 13

Some mechanisms (selection + migration) are deterministic –> can we predict across time y scaling up mechanisms or do other factors that some into play that make it more difficult

Are the dP equations enough to explain macroevolution

Question 14

Body size example

Answer 14

Do we see NS favoring outcomes that let us infer inevitability about patterns of change
- Active vs. Increase in trait value based on passive trend

Cope = observed that large body organisms evoloved from smaller ancestors –> see tendency towards large body size

Cope could be true or could just be passive process

Question 15

Inevitability of large from small

Answer 15

Larger organisms evolve form smaller because the largest organisms are necessarily larger than ancestors smaller than them

This observation is not sufficient to know this is a driven trend where NS favors large

Question 16

Evidence for NS favoring Trait value

Answer 16

Change in bounds of distrubution = evidence NS favors Trait value

Question 17

2nd hypothesis about passive vs. active

Answer 17

In Passive trends apparent driven pattern on the whole clade is built from even distributions of change within clades
- Entire phylogeny looks like decedents have larger trait value BUT how is it in the different components of the phylogeny

Question 18

Looking at second hypothesis of Passive vs. Active

Answer 18

Image – Across phylogeny not one phylogeny does it match or is it equally likley to go both ways

Through time look at size of circle –> see large at end compared to when starts –> seems to confrom to Cope = favored by NS

BUT lookiing at subclaves across phylogeny = see increase TV BUT the increase is because of ONE change in one branch = only happened once
- Just had change once in phylogeny = Trait value chnage in the end BUT it is not favored in across lineage – just happend once

Question 19

Curve showing second prediction of favored vs. passive

Answer 19

A and C = not chnaging and B changes –> change in one in common ancestor and then body size chnage in random way

A driven trend would have to be across subclaves
- B – larger in that subclave and A and C would also have to get larger in subclaves rather than just a chnage in one branch from smaller to larger

Question 20

3rd prediction in Passive vs. Active

Answer 20

In driven trends individual ancestor descendents changes are biased in one directions

***Not the case in passive

Example – Diansours –> look at invidious change in body size across phylogeny and see if there is pattern change in particular direction
- Examine direction of trait evolution along indiviual lineages

See green is harger and red is snaller – see if randomly distrubuted in either driection

For driven – 8/12 lareger – trend to increase = biased in direction of evolution

For passive – trait change can be even number of increase of decrease but might have one big shift that chnages the mean across phylogeny

Question 21

Null model

Answer 21

Passive trends are essentially the null model

Paleontologists are generally reluctant to assign patterns to driven trends without substantial corroborating evidence from multiple lines
- Are this way becasue know that paaasice can occur = high threshold to sat trait is due to favore by NS
- One prediction might not be enough = look for more lines of evidence to back hypothesis

Question 22

Driven trends in fossil record

Answer 22

There are some definte driven trends observed in the fossil record

Example:
1. Body size being favored in horses (body size increases) – in horses have a trend in body size but other aspects of horse evolution that is driven such as specialization of digits (run on middle finger – 5 –> 3 –> 1)
- Seems to be across lineages –> driven NS favoring outcome in lineages

2. Simplification of skulls in mammals
   
   • Most mammalian reptiles Jaw joining is complex
   • Through time complex reduces and some bones evolved in flexible jaw to become inner ear bones
   • Process of simplification = driven change –> have many lineages favored by NS
   • Solid Jaw + auditory bone for hearing = favored acriss ancestors

Question 23

Seeing interactions in fossil record

Answer 23

Co-evolution – can’t see in fossil record to see specialized interactions (hard to see interactions)

BUT can see interactions we know today and can assume they went on in the pat

Question 24

Example - long term co-evolutionary trend

Answer 24

Running mammals vs. Ungulates

Can understand how they interact today –> assume past interaction

Look at interactions – what dictates outciome of hunts = median term speed of predator and prey –> who wins in rates dictates outcome of interactoon

Can look at anatomy that correlates with speed and apply undersatdning to morohs in fossil and see how fast running speed over time

They went through fossils – looking at features coreelating to running speed

Reults: 3 clades of predator mammal that exists through time period
- #1 trait that correlatd with speed = metatarsal femur index
- Can see driven trend for speed in ungelates= ungelates min and max change through time – mives together –> ungelates = faster not just few are faster ALL are –> many are faster now
- Predators –> don’t show driven trend – speed is passiove - some are fatser but the minimum is not changing

Question 25

Explaining co-evolutinoary. change

Answer 25

Overall: Outcome of capture deopends on footseed --> NS is string in prey but not in predator 3 options for why this might be the case: 1. Trophic structure and demographics 2. Stronger tradeoffs for predators 3. Selection on predators maybe weaker

Question 26

Option #1 for co-evolutionary change

Answer 26

Overall: Trophic structure and demographics Trophic structure -- always have smaller amount of predator than prey Looked at effective popultion size -- predator smaller popultion size = weaker selection AND higher drift + get lower number of new mutations - Prey = more indiviuals getting mutations = more mutations for faster in prey + NS is stringer in prey than the smaller predator (predator also has more dirft)

Question 27

Option 2 for co-evolution outcome

Answer 27

Overall: Stronger tradeoffs for predators Tradeoff is compenent of speed or can be limited on degree of how speciated fir speed - Traits conbtrollubg limb developemnt Tradeoff - example of Antagonistic pleitropy -- gene for limb might increase soeed but might decrease other asoect of fitness

Question 28

Option #3 for co-evolution

Answer 28

Overall: Selection on predators may be weaker Prey killed --> predator can take advatantge of weaker in prey = this might be less consequence Can look At functional repsinse curve - If mean popultion fitness of prey increases = popultion density increase 00 as prey density invcreases = capture rate increases because more individuals to capture = predator might not need to adapt because more prey to begin with

Question 29

Fuynctional response curve

Answer 29

Density of prey vs. Number of prey consumed

Question 30

All explination for change in co-evolution

Answer 30

Pattern of evolution changes over time BUT all are explained by rooting in mechanisms of evolution in ecological context - Same mechanisms occuring today Constraint of NS or ecological interaction that shape strength of NS Million years that change but by our mechanism of evolution --> Analyze large patterns and see from lense of mechanisms of evolution

Question 31

Questions on Patterns of diversity through time

Answer 31

How has biodiversity changed over the history if life? Are there patterns of diversity that indicative of macroevolutionary phenomama?

Question 32

Potential trends of diverity

Answer 32

Has diversity been increasing OR -- did it saturate early (low then increase then plataue -- stable through time)

Question 33

Second question about diversity

Answer 33

Has taxonomic composition of diversity changed or did diversity stay constant? Does the diversity stay constant or does change in composition if diversity come from moving alteration to diversity as a whole OR were taxonomic changes associated with major changes in diversity?

Question 34

What drives patterns of diversification

Answer 34

Patterns of diversification are driven by the balance between speciation rate (alpha) and the extiction rate of lineages Pattern of diversification = result of two parameters acting against each other: 1. Speciation rate --> create new lineages 2. Extiction rate Net result that drives pattern of biodiverity

Question 35

Looking at patterns of biodiverity

Answer 35

People look at pattern of diveristy through time but looking fossilo reocord -- specifcially lookung at marine organisms (mollusks) with hard shells because they fossilize a lot (good record) Sedimentary rock form marine envirnment -- have record of organisms that live there -- see fossil record to see how diverity changes through time

Question 36

Patterns of diversity over time

Answer 36

Family level diversity in marinbe invertabrete fauna through the phanerozoic era Results: Doveristy has clearly chnaged through time + the diverity of that diverity has changed (rare groups become more abdundant and visa versa) PLOT -- shows diverity change through time - Increase in diverity thorugh time then short decrease then increase through Parts of fossil - Types of diverity change over time --> repaltive abundence shifts over time - Have turnover in composition of diverity through time

Question 37

Exitiction

Answer 37

We think about exitiction as this unnaturak thing that humans on biodiverity Example -- humans drive species to extivction through hunting - We think about it from negeitive way that hurts the natural order BUT doesn't mean that how exoection operates in every case Exiction = natural part of evolutionary processes --> understanding varaution in rate of extiction through time assumes that there is varaition in rate - Use fossil record data to undersatnd varaition in backgroun exitction rates in ecosystems

Question 38

Diverity is net result of

Answer 38

Diversity is net result of speciation and extinction ***Patterns of extinction are crucial to understanding macroevolutionary patterns

Question 39

Background extiction

Answer 39

Normal rates of extinction are referred to as "Background extiction"

Question 40

Species have

Answer 40

Geologic life spans

Question 41

Calculating extiction rates

Answer 41

Extiction rates are calculated as the proportion of geologic lifespans that end over a given time interval - For how long do we see a group of organisms before we don't see them again PLOT -- Frequency plot of marine genus level excitations over 1 million year internals (look in given million years how many lineages go extict) - Distribution that sounds high BUT doesn't show distribution fully because has statistical anomalies on scale that have rates that are higher than expected of base background Result: Mean genus lifespan = 4 million years - Most of the time Shows extcition is high (a lot of lineages go extict)--> 25% of genera in fossil record go extict per million years - AT the tail end = backgroun extiction is low -- shows that there has been a lot of variation in exitction rates through time with some periods of higher rates

Question 42

Exiction rate through time

Answer 42

Plot shows that there has been a lot of variation in exitction rates through time with some periods of higher rates

Question 43

Plot of extcition rates through time

Answer 43

Shows spikes that appear at the junctions of many geologoc periods - Plot = looks at genera --> very dramatic - Shows 5 major mass exictions events that are statsitical anomlies - Spikes = associated with shifts in composition of biodiverity --> see change in levels of diveristy and in what makes up the diversity 5 spikes were associated (not just identifiable shifts in fauana but ALSO have major restructuring of the biosphere) ***Have profound changes at the genus level - 85% of gernera lost in one and 96% of genera lost in other -- profound change in biodiveristy

Question 44

What defines geologic periods

Answer 44

Defined by the different kinds of fossils

Question 45

KPG exiction

Answer 45

Most famous -- brought the cretaceous period (age of dinasours) to a close - Brought in age of mammals Ended 160 million years of dinasours being terestrial vertaberete dominance - Profound change -- all dinasours died --> makes room for mammals ***Was actually the smallest of the big 5 mass exitctions

Question 46

What caused dinasour exitction (KPG)

Answer 46

Overall: Due to extraterestial impact -- astroid put into motion quickly Mechansism seen in the 1980s -- Have Iridium deetcted in the rcok (thin black line) --> black iranium is abundent elswhere in solar system --> influx of iradium = result of extraterrestrial impact - can see the depression crater of event - Rock hit + fires + fell into ocean that causes Tsunamis + ash and dust + debris all over atmsophere that blocked the radiation = put nial in coffin for organisms living

Question 47

Envirnmental change in KPG

Answer 47

Debate is if the astroid was smoking gun or other things ==> diversity decreased in some amount but now know impact set the stage for extiction - Likely major envirnmental changes going on at the time BUT the effect on diverity was minor in comparasion

Question 48

Size of rock in KPG

Answer 48

Big but not size of earth -- size of binghamtont Throws off ecosystems to through off biodiverity of the planet

Question 49

Largest mass extiction

Answer 49

End of the permian - 252 Million YO 30 Million years before diansours existed Earth had dramatic animal biodiverity --> dominant terrestrial = reptiles that are more closley related to us (our side - mammal like reptiles)

Question 50

Permo-triassic

Answer 50

Wiped out 96% of the animal species on the planet - Close to experiment of life ending Eveolutionary recoveroty in the Triassic was very slow The extiction appeared to happen relativley rapidly -- in 200,000 years have creash

Question 51

What caused permo-triassic

Answer 51

No evidence of an extraterestial impact -- BUT in 200,000 years have evidence of envirnment changes building - Atmosphere change + climate change + ecosystem change Overall: Due to change in earyj --> change in volcanic activity - Evidence --> siberian traps -- have piles of ogneous rock - came from magma coooling on earth (huge amount of rock) - Had massive volcanisms (like gaping wound on earth where rock bubbled for years) --> gasses change atmopshere = goty ocean anoxia + massive warming

Question 52

Earth in Triassic

Answer 52

Earth was an ecological wasteland in the begiinning of the trassic (desolute) - >90% of terestial vertabretes (biomass) 5-10 million years after exitction belongs to a single burrowing genus -- underground = got through -- all the diversity we had for a while - 3 million years after mass exotction continue warming psuhed almost all animals out of the tropics

Question 53

Atmospheric event in Permo-trisassic

Answer 53

Atmopsheric event continued through for 3 million years --> ocean temperatyres Averaged 40 celius (104 F) Average across globe = life was pushed out of the tropics Took long time to retrun to normal and stabilized to have diveristy

Question 54

What changed the course of life in Mass exitctions

Answer 54

In all the ME historical events outside of the mechansims of evolution had a profound effect on the course of life (major change to bio diveristy) Major shifts in taxonomic composition are usually assocated with extrinsic exitction evnets

Question 55

Mechanisms of evolution + History

Answer 55

Mechanisms + history = can go hand in hand --> osoelation of warm to cold -- can see changes due to mechanisms BUT large remodeling events we see are unable to explain just in our deltaP equations Exception to being able to explain things in predictable ways - Outside factors = important in picture of life on earth - Need to think about macroevolution provess neeed to deal with external factors as well

Question 56

Were people destined to take over

Answer 56

People think that mammals were detsined to take over the world BUT this is not the case that we would just outcompete over time Image -- Ecological competition of mamals vs. dinasours -- can see what it would look like if outcompete iver time - Can see that as mammals expand the diansours are driven to extiction Reality = this is not what we see

Question 57

Reality of mammals + dinasours

Answer 57

Diveristy to thin then get extiction before can take up space and take area External event that allows other organisms to flourisg Dinsours + mammals have been on earth for the same amount of time -- nothing about mammals that would take over in world without astrpid --> wouldn't outcomepete before astroid

Question 58

Why did linease flurish after astroid

Answer 58

Astroid = major change in oceans Before KPG = major plantin = radiolarians After KPG = Dioatons took over as the main atotrophs Radiolarian varaition decreased and Diatom increased over time WHY -- Diatoms in Crotesiuc = were in the poles AND diatoms odat and dormencey --> month have 6 months of light and then they go formnet until get more light --> good trait that is useful to get through the world wide darkness = have leg up to recievry - Dormencey likley allowed them to better survive the climatic upheaval

Question 59

Diatom evolution

Answer 59

Diatoms evoloved to do better in Mass extiction just happened ot have it happen to help Act on traition varaition that exists (had it to begin with) -- did not evolove it before to help for the ME

Question 60

Patterns of new lineages outcompeting old in the absence of ME?

Answer 60

Have example where ecology cause one to beat another when came into contact Look at indepentdent evolution and then what happens when converge with each other Example - Great American Biotic intertage

Question 61

Great American biotic intertage

Answer 61

For alsmost all Cenozoic SA animals had been evoloving in complete isolation --> Popultions by its own unique marsupials and placental lineages - Before NA and SA were seoperated (SA was own weird species evoloving since dinasours) THEN the Isthmus of panama formed and NA and SA animals came into contact - As sea levels decreased = cause NA and SA to be connected = free to move back and forth (first things that can swim

Question 62

Did one win in Great American biotic intertage

Answer 62

In one way = no win or lose vecayse diverity inreased in both continenets and are moving to habiatsts - No win or loss as long as diverity increases in both places BUT some win/lose Example -- NA things from SA orgin --> Few things are in NA and organisms that are the result of lineages of SA origin VS soun american mammasl of NA origin Result: See Asymetry in which ecosoystem won -- SA ecosystem = out competed by the NA lineasges that they were in cotact with (Have more SA mammals of NSA origin than NA mammals of SA origin)

Question 63

Reason NA won

Answer 63

Face NS average not as isolated = mamamls in NA had been tested by competition with other organsims but SA organsims didn't Cause of becoming dominant through time due to NA + Asia diverging and coming back --> evolve --> then spill --> then outcompete See competative exclusion --> Have evoloving ecological processes driving diverity

Question 64

Two last Macroeveolutionary concepts

Answer 64

1. Apparent evolutionary stasis -- lack of change in some lineages in fossil record 2. Uncanny similarities across lineages (between unrealted organisms)

Question 65

Norm during earth's history

Answer 65

Change has been the norm during earth's history - Earth is changing + organisms change

Question 66

Change in the fossil record

Answer 66

We don't often observe as much change as we expect in the fossil record + not as linear - If morphospecies are lucky enough to survive for a long time in the fossil record they often show few signs of steady directional change - If persists for a long time --> sometimes fossils don't show patterns of driectional change -- fossils seem to stay similar --> no directional to suggest drive by NS

Question 67

Patterns for things not changing

Answer 67

Patterns for things not changing = seen in marine organisms --> would think they would adapt through time BUT this is not what we see often

Question 68

Expected pattern of change

Answer 68

If evolution is a gradual process = we might expect to see pattern of change through time like image IMAGE X - Axis -= change in trait Y - Axis = time/diverisfication Have slanted lines --> gradual shift as linage diverge - See Morphology changing gradually as lineages diverse BUT this is not what we see

Question 69

What do we see in the fossil record

Answer 69

IMAGE 1. Lineages stay the same through time and have no trends in one directions 2. Change in fossils is accompanied by speciation events - Morphological change associated with new lineages occur very abruptly in geologic time and then remian constant within lineages for long stretches of time

Question 70

Puntuated Equillibrium Proposal

Answer 70

In the 1970s Goulds and Elderge proposed a model that explains the pattern of morphological stasis followed by leaps of divergence -- proposed Punctuated equilibrium

Question 71

Puntuation Equillibium

Answer 71

Morphological stasis occurs because popultions are at an equilibrium where NS isn't pushing them in a particular direction - Model explains stasis in the fossil record - Equilibrium driving lack of change and then being punctured by something that allows change - Some equilibrium acts on lineage then that prevents them from evolving in either direction

Question 72

Is punctuated equilibrium just envirnmental equilibrium

Answer 72

Envirnmental equilibrium = NOT actually puntuated equilibrium -- just how it was interpreted - People think that it is indicative of envirnmental Equilibrium -- that the envirnment is not pushing one way or the other for a long time = Not pushed by NS --> and then have rapid envirnmental change

Question 73

Equilibrium in Puntuated Equilibrium

Answer 73

Genomic Equilibrium based on mechanisms of evolution Equilibrium = prevents NS allowed them to adapt

Question 74

What is Genomic Equilibrium driven by

Answer 74

Driven by widespread epistasis -- change in body requires complex epistasis = evolution is difficult Epistasis = constraint on NS ability.to drive change

Question 75

Why does morphological stasis occur?

Answer 75

Morphological stasis occurs because populations ate stuck on adaptive peaks surrounded by deep fitness valleys - Lineage stays the same through time because stuck on peak of AT --> change requires pass valley

Question 76

Stuck peaks in morphological stasis NOT like

Answer 76

It is not like you need to have a slight shift in fitness -- more like population is on a peak and can't shift in either direction because have massive fitness decrease due to polygenic constraint on traits

Question 77

Book explination for process in PE

Answer 77

Just saying that the morphological change occurs during speciation events -- oversimplifications

Question 78

Type of speciation in PE

Answer 78

Peripatric speciation -- have a satilote popultion elswhere = huge amount of drift Have the kind of massive drift needed to knock off of peak

Question 79

Process of Morphologocal change in PE

Answer 79

Peripatric speciation -- from founding new popultion from 2 indiviuals = allows NS to get off peak to new one ***Hard to do without strng dirft

Question 80

Example of PE

Answer 80

A large population of mice across a continent exists in evolutionary Equilibrium + there is some barrier that mice can't cross Mice = on an apdative peak --> not pushing off even if conditions change bevause of epistatic constraints THEN some event and one mice gets across the barreier to new habitat = have a founder event NOW have big change in alllele frequnecey + have drift --> leads to NS to change allele frequencey in way it couldn't before - Not just NS -- first drift then NS acting on varaition NOW say mice have bigger bodies --> eventually mice go back to habiatat and eventually only have big body left

Question 81

What would PE look like in Fossil record

Answer 81

See something like image --> miss the change because it happens rapidly in a small popultion far away (in popultion that split) Seems like population pop out of nowhere because its from peripatric speciation

Question 82

PE vs. Wright

Answer 82

PE is like wrights theory --> NS can't cause change in body structure on own = need to invoke other evolutionary forces Shows how can happen in absence of environmental change

Question 83

Why look at convergent evolution

Answer 83

See role of deterministic process -- how predictable is evolution

Question 84

What does Convergent evolution show

Answer 84

Evidence in favor of determinism -- comes from striking examples of convergent evolution - Striking similarity from unrelated individuals - See the same solution to same problem in different lineages

Question 85

NS as determinatistic

Answer 85

NS is determinanistic by itself --> can we scale that up to what happens to evolution

Question 86

Example Convergent evolution

Answer 86

Placental vs. Marsupial predators Similar in overall shape and body composition BUT they are of unrelated origin - Get the same solution to be apex predators in 2 different envirnments in unmrelated lineages

Question 87

Example convergent evolution on the broad scale

Answer 87

Flight -- Asking would we get flight again? Look at how many times flight has happened -- Answer is 4 times - Have 3 groups of organisms today and 1 extict - Get very unrelated organisms find ways to fly BUT there are limits in the organisms that can fly Result: Only 4 groups can fly -- all others can't fly Would we get flight again? -- Maybe because we got it 4 times BUT all the times are limited - Possible it could occur independtely but many not inevitable if only happened 4 times

Question 88

Question in looking at CE

Answer 88

Looking to see if certain traits are lilkley to evolove if start over again -- are there certain traits that evolved multiple times

Question 89

Evolution of marine predators

Answer 89

Solution to hydrodynamics -=-> get organisms with similar body designs from unrelated

Question 90

Convergence over a range of timesclaes

Answer 90

Can occur over multiple timescales -- show up across broad phylogeny across long periods of time

Question 91

Looking at phylogeny across mamals

Answer 91

Across phylogeny of mammals = more convergene First -- 2 groups in mammals that evolove similarly independently --> then have marsupials limited range of patterns to being predators THEN -- Even further back to mamaml like reptiles = see similar patterns there --> have same body shape Overall: Something about design to be predator showed up across 100s Million Years in many lineages

Question 92

Marsupial Placental

Answer 92

Example of High CE in predators -- have similarities between groups of organisms --> Arive at similar solutions Ex. Skulls of Thyalcine + Gray wolf = very similar even though unrelated

Question 93

Example of CE in mammals #2

Answer 93

Moles --> Same solution to be underground animals that leads to similar body pattern --> high convergent between groups of unrelated indiviuaks

Question 94

CE in plants

Answer 94

Seen in plants --> thinks with suculent plants (have spikes + not regular leaves) BUT they are not cacti They are an old world group of plants in Africa that are hard to tell from cacti - Similar envirnment --> leads unrealted groups of plants that end woth the same design and development outcome to deal with harsh conditions

Question 95

Convergent Evolution on Smaller Timescales

Answer 95

Convergence also occurs on smaller timescales Example -- Antillees islands --> All have the same ecological niche being filed with convergence in ecological niche - Whole community convergent across groups - Evoloved and radiated to fill same niche = get niche with parallele convergence

Question 96

What does convergence tell us?

Answer 96

Does it tell us that NS is deterministic or is it determined due to constraints??? Is it a matter of repeated optimization or common constraints

Question 97

Idea for same form appearing

Answer 97

Perhaps the same form appears over and over because of limits on the process generating variation - Maybe have to do with the power of NS or limitation of NS (Common solution that is possible given constraints of living systems) Don't know which it is

Question 98

Example Constaint

Answer 98

Centapeads -- Very diverse BUT they inly ever have an odd Number of body segments even though they are very diverse - Have the same construction (can't have even number of body segments)

Question 99

Final Answer to What does CE tell us

Answer 99

No final answer to what CE tells --> When we see it -- how to reconcile with historical happenstance where see the same patterns -- does it tell us anything about what biodiversity we expect if restarted earth