Key to the diversity and history of Life

114 Pages·2014·5.025 MB·English

by  Shipunov, Alexey.

Key to the
Diversity
and History
of Life
Alexey Shipunov
December24,2019
Shipunov,Alexey.KeytothediversityandhistoryofLife
December24,2019version.114pp.
URL:http://ashipunov.info/shipunov/school/biol_111/ph_key/ph_key.pdf
Thisbookisforanybiologystudentwhowantstoknowthesubjectbetter.Iconcen-
trateonthehistoryoflife,diversityofplants,protistsandanimals,andsomeother
generalaspectsincludingelementsofbiogeography.
Onthecover: NikolajZinovjev,“DevonianPeriod”(1968)
Thisbookisdedicatedtothepublicdomain
Contents
1 TheReallyShortHistoryofLife 5
1.1 OriginofLife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 ProkaryoticWorld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3 TheRiseofNonskeletalFauna . . . . . . . . . . . . . . . . . . . . . . . 9
1.4 FillingMarineEcosystems . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.5 FirstLifeonLand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.6 CoalandMudForests . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7 PangeaandGreatExtinction . . . . . . . . . . . . . . . . . . . . . . . . 16
1.8 RenovationoftheTerrestrialLife . . . . . . . . . . . . . . . . . . . . . 17
1.9 JurassicPark: WorldofReptiles. . . . . . . . . . . . . . . . . . . . . . . 18
1.10 TheRiseofContemporaryEcosystems . . . . . . . . . . . . . . . . . . 20
1.11 LastGreatGlaciation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2 DiversityofLife 26
2.1 Diversitymaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.2 Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3 LifeStories 64
3.1 FoundationsofScience . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.2 FewDropsofGeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.3 ChemistryofLife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.4 VeryBasicFeaturesofLife . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.5 HowtoBetheCell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.6 OverviewoftheCell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
3.7 EcologicalInteractions: Two-SpeciesModel . . . . . . . . . . . . . . . 75
3.8 Howtobecomeananimal . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3.9 Howtobeananimal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
3.10 Animalia: bodyplans,phylaandclasses. . . . . . . . . . . . . . . . . . 80
3.11 Peasandflies: basicsofinheritance . . . . . . . . . . . . . . . . . . . . 84
3.11.1 Syngamyandmeiosis . . . . . . . . . . . . . . . . . . . . . . . . 84
3
3.11.2 Maleandfemale . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.11.3 Mendel’stheory,explanationsandcorrections . . . . . . . . . 84
3.11.4 AnaphaseIandrecombinants . . . . . . . . . . . . . . . . . . . 85
3.12 Plantstories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.12.1 Plantsandplants . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.12.2 Lifecycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.12.3 Threephylaofplants . . . . . . . . . . . . . . . . . . . . . . . . 90
4 GeographyofLife 93
4.1 Idealcontinentandrealcontinents . . . . . . . . . . . . . . . . . . . . 93
4.2 ArchitecturalModelsofTropicalTrees: IllustratedKey . . . . . . . . . 98
4
Chapter 1
The Really Short History of Life
History of Earth is split in multiple intervals, and some of them are listed in the
clockandchartbelow. Theseclassifications,however,donotreflectwellthestages
of evolution. This is why in this chapter, the history of life is described from the
palaeoecological point of view which reflects milestones of organic world develop-
ment.
66 Ma 4.6 Ga
252 Ma
C
M e
541 Ma Paleoz esozoic nozoic Hadean 4 Ga4.0 Ga
oic
1 Ga
n
Protero Archea 3 Ga
zoic
2 Ga
2.5 Ga
Geologicclock.
5
numerical numerical numerical Eonothem numerical
Series / Epoch Stage / Age age (Mya) Series / Epoch age (Mya) Series / Epoch age (Mya) / Eon Erathem / Era System / Period age (Mya)
ary Holocene 0p.r0es1e1n7t ~ 145.0 358.9 ± 0.4 Ediacaran 5~41 6.03 ±51.0
ern Upper Upper proNteerooz-oic Cryogenian ~ 720
atPleistocene Tonian
Qu c n 1000
Pliocene 2.58 assi Middle onia Middle Meso-
nozoic Neogene Miocene MesozoicJur Lower 201.3 ±0.2 Dev Lower 419.2 ±3.2 mbrian Proterozoic pprrooPttaeelrreooozz-ooiicc 1600
Ce 23.03 ca
e Oligocene assic Upper Silurian Pre arNcheeoa-n 2500
oic ogen Eocene oic Tri Middle oicc 443.8 ±1.5 hean aMrcehseoa-n
Phaneroz Pale Paleocene MaDasatnriicahntian 7266.116 ..±600.2 Phaneroz mian Lower 251.902 ±0.024 PhanerozPaleozoiOrdovician MUpidpdeler Arc aaPrrccEahhloeeeH-oaa-anndean ~ 44060000
Campanian er Lower
83.6 ±0.2 P
Upper Santonian 86.3 ±0.5 485.4 ±1.9
Coniacian
s Turonian 89.8 ±0.3 zoic
c u 93.9 o 298.9 ±0.15
Mesozoi Cretaceo Lower CVHBeaaanlAAuaroprltnbmeetgiimraaaiinvnnniaiiaaiannnn ~~~~1 11110122303592.5....0049 PaleCarboniferoussissippianPennsylvanian Cambrian
Berriasian ~ 139.8 Mis
~ 145.0 358.9 ±0.4 541.0 ±1.0
Chronostratigraphicchart.Simplifiedfromhttp://www.stratigraphy.org/index.php/ics-chart-timescale.
1.1 Origin of Life
NikolajZinovjev,“ArcheozoicEra”(1968)
In the strict sense,origin of life does not belong to biology. In addition,biologists
werelongfoughtfortheimpossibilityofaspontaneousgenerationoflife(whichwas
acommonbelieffromMedievaltimestotheendof19century).Oneofthefounders
of genetics,Timofeev-Resovsky,when he was asked about his point of view on the
originoflife,oftenjokedthat“hewastoosmallthesetimes,anddonotremember
anything”.
However,contemporarybiologycanguesssomethingaboutthesetimes. Ofcourse,
suchguessesarenomorethantheoriesbasedoncommonscientificprinciples,ac-
tualityandparsimony.
First,Earthwasverydifferent. Forexample,theatmospherehadnooxygen; itwas
much closer to the atmosphere of Venus than to the atmosphere of contemporary
Earthandcontainednumerouschemicalswhicharenowpoisonousformostlife(like
CS orHCN).However,bytheendofArcheanfirstoxygenappearsintheatmosphere,
2
and in early Proterozoic,it started to accumulate rapidly. The process is called the
“oxygen revolution,” and it had many consequences. But what the reason for oxy-
7
genation was nothing else than the appearance of first photosynthetic organisms,
mostlikelycyanobacteria.
Second, the first traces of life on Earth are suspiciously close to the time of Earth
origin (4,540 mya)— molecular clock place LUCA about 4,000 mya, and recently
foundfirsttracesofcyanobacteriaare3,700mya.Altogether,lifeonEarthwasmost
ofthetimeofitsexistence!
Third, first living things were most likely prokaryotes (Monera, bacteria). These
could be both photosynthetic (cyanobacteria) and chemotrophic bacteria, as evi-
dencedfromisotopeanalysisofIsuasedimentaryrocksinGreenland,andnowalso
fromthepresenceof stromatolites,thetracesofcyanobacteriainthesameplace.
What was the first living thing? It has a name LUCA,Last Universal Common An-
cestor,butonlyalittlecouldbeestimatedaboutitsotherfeatures. Itwasprobably
a cellwith DNA/RNA/proteinsstream,likeall currentliving things. Unclearis how
thisstreamappearedandhowithappenedthatitwasembeddedintothecell. One
ofthehelpfulideasis“RNAworld”,speculationabouttimeswhennoDNAyetexist,
andevenproteinsdidnotfunctionproperly,butRNAsalreadyworkedasaninfor-
mationsourceaswellasbiologicalmachines.Anotherpossibilityisthatlipidglob-
ules, some other organic molecular and water formed coacervates, small droplets
inwhichtheseRNAscoulddwell.Ifthishappened,thenresultedstructurecouldbe
called“proto-cell”.
1.2 Prokaryotic World
Most of the Proterozoic prokaryotes (Monera) dominated the living world. Typi-
callandscapethesetimeswashigh,almostverticalrocksandshallowplains,which
shouldbecoveredwiththetidefordozensofkilometers.Thisisbecausetherewere
noterrestrialorganismsdecreasingerosion.Oceanwaslowoxygenated;onlywater
surfacecontainedoxygen.
In those conditions,ancestor of eukaryotes appeared. First eukaryotes could prob-
ably remain contemporary heterotrophic Excavata (Fig. 2.3) like Jacoba, but there
are no fossils of this kind. However, there is a number of fossils which could be
treated as algae, photosynthetic protists. These fossils remind contemporary red
andgreenalgae(Fig2.9,thebottomrow).ItispossiblethatsomeotherProterozoic
fossils(acritarchs)belongtootherprotistgroups,forexample,unicellularDinozoa
(Fig.2.8).
Ecosystems of these times were similar to Archean and mostly consisted of cyano-
andotherbacteria,andrepresentednowbystromatolites.Noonecansayanything
8
aboutterrestriallifeinProterozoic,butitpossiblethatMoneradominatedthereas
well.
AttheendofmiddleNeoproproterozoic,continentsofEarthjoinedinonebigcon-
tinent Rodinia; this triggered the most powerful glaciation in history, “snowball
Earth”,Cryogenianglaciation.
1.3 The Rise of Nonskeletal Fauna
Thismentionedaboveglaciationpossibly,inturn,triggeredtheevolutionofEarth,
because,intheEdiacaranperiod(thelastperiodofProterozoic),animalsandother
multi-cellularorganismappear.TherearethreemostunusualthingsaboutEdiacar-
ianecosystems.First,theywerefilledwithcreaturesassimilartocontemporarylife
aswould(notyetdiscovered)extra-terrestriallifebe.Inotherwords,they(likePteri-
dinium,see Fig.2.30) had no similarity with the recent fauna and flora. Second,all
these Ediacaran creatures were soft, nonskeletal. This last fact is even more strik-
ing because,in the next period (Cambrian),almost all animals and even algae had
skeletalparts.
There were different types of ecosystems in Neoproterozoic. However, in essence,
they all consisted of these soft creatures (it is not easy to say what they were,ani-
mals,plants of colonial protists). They thrived for about 90 million years and then
suddenlydeclined(someleft-oversexistedinCambrian,though).Thisdeclineisthe
thirdbizarrething.Weirdbecauselaterecosystemsalmostalwaysleftdescendants,
even famous dinosaurs went extinct but left the great group of birds, their direct
“offspring”.
Whytheywentextinct,itisnotclear.Severalfactorscouldbeblamed:oxidizationof
ocean,the appearance of macroscopic carnivores,increased transparency of water.
Thelastcouldrelatewithtwofirstbymeansofpelletproduction.Manyrecentsmall
plankton invertebrates pack their feces in granules (pellets),which speedily fall to
theoceanbottom.InEdiacaran,therewasprobablynopelletproduction,andthere-
foreoceanwaterwasmostlymuddy.Whenfirstpelletproducersappear,waterstart
to be increasingly more transparent,which raised oxygen production by algae and,
asthenextstep,allowedmoreandbiggeranimalstoexist.Biggerplanktonanimals
mean that it starts to be rewarding to hunt them (remember ecological pyramid).
Thesehunterswereprobablyfirstmacroscopiccarnivores,whichcausedtheendof
Ediacaran’s“softlife”.
AfterEdiacarangreatextinction(thisisthefirstdocumentedgreatextinction),one
canobservetheriseofverydifferentcreatures,small,skeletalCambrianorganisms.
9
They appear insignificant diversity and represent many current phyla of animals.
Thisiscalled“Cambrianrevolution”,or“Cambrianexplosion”(seebelow).
1.4 Filling Marine Ecosystems
NikolajZinovjev,“SilurianPeriod”(1968)
This happened during the Cambrian and Ordovician periods,which jointly contin-
uedforalmost100millionyears. MostofthistimetheEarthclimatewasrelatively
warm,butcontinentswereconcentratedintheSouthernhemisphere.Attheendof
Ordovician,AfricahittheSouthPole,andthisresultedinaseriousglaciation.
The sea,in large degree,prevailed over the land and thus created exceptionally fa-
vorableconditionsforthedevelopmentofmarinecommunities,whichinthisepoch
became finally similar to what we see around now. For some groups,there was not
“enoughspace”inthesea,and,asaconsequence,thecolonizationoflandfromhigher
organismsstarted.
At this time, all main types and even classes of invertebrates and vertebrates and
terrestrialplantsalreadyexisted.Stromatoliteswenttothe“background”ofecosys-
temsandwerereplacedwithotherbuildersofbioherms(reef-likeorganicstructures)
10