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03 Az evolúció és a bioszféra

2014.09.19

Evolution

The Evidence for Evolution

Direct evidences:

  • Fossils: they are quite rare
  • Relative chronology : strata (layers) represent different periods: older stratum is located in a deeper position
  • Absolute chronology: can be measured by radioactive isotopes (14C t1/2=5700 years, 40K t1/2=1,28 billion years)

Indirect evidences

  • Cell: organelles, chromosomes
  • Morphology
  • Homologous organs: common origin but different function (pentadactyl limb)(process: divergency)
  • Analogous organs: different origin and the same function (Wing of a bird and of an insect) (process: convergency)
  • Molecular evidences: DNA, genetic code (protein synthesis), proteins
  • Geographical distribution: Darwin-finches, animals of South America and Australia)

 

Events of Evolution

 

Big Bang (15 billion years)

Birth of the Solar System and Earth (4.6 billion years)

Solid surface, water (ancient ocean)

Ancient atmosphere: NH3, H2, CH4, H2O

UV-ray, lightning: simple organic molecules (amino-acids, aldehides, acids)

Ocean: macromolecules (water protects from UV, minerals as catalysts)

Birth of the cell: coacervate, chemoton

  • Lipid border
  • Metabolism
  • Genetic material

Early history:

  • Heterotroph, anaerob cells (enough organic material in oceans)
  • Autotroph anaerob cells: O2 level increases (poisonous for anaerob organisms!), ozone layer protects from cosmic rays
  • Autotroph and heterotroph aerob organisms

Multicellular organisms

  • 1-1.5 billion years ago

 

Paleozoic (óidő): 570-230 million years ago

Cambrian (kambrium): in oceans: molluscs, echinoderms, trilobites

Ordovician (ordovicium): algae try to conquest the continents

Silurian (szilur): the first land plants and first fish

Devonian (devon): armored fish, first insects, amphibians (first land animals), ferns (land plants), lobe-finned fish, first sharks

Mississippian, Pennsylvanian (karbon): giant marshlands, coal formation, first reptiles, first gymnosperms

Permian (perm): evolution of reptiles, dry and hot climate. At the end of permian 95% of livings die out

Mesozoic (középidő) (230-65 million years ago)

Triassic (triász): gymnosperms rule. Dinosaurs, ammonites, first mammals and first turtles

Jurassic: pines (Sequoia), dinosaurs, first bird (Archaeopteryx)

Cretaceous (kréta): giant dinosaurs, Triceratops, Tyrannosaurus rex. First angiosperms. Marsupial and placental mammals

End of Mesozoic: comet impact (?) Extinction!

Cenozoic (Újidő) 65-0 million years ago

Tertiary (harmadidőszak): Continents move to the present-day position. Adaptive radiation of mammals (Marsupials survive only in Australia). First hominids

Quaternary (negyedidőszak): human evolution. Ice ages: mammoth, mastodon

 

Human Evolution

Ancient mammals: insectivorous teeth

Primates:

  • Number of teeth is reduced: incisors, canines, molars
  • Pentadactile limb: five fingers (adapted to catching), thumb is opposable
  • Eyes look forward

Ancient apes:

Dryopithecus 15 million years ago), Rudapithecus hungaricus (Rudabánya, 10 million years)

Early hominids:

Australopithecus species („déli majom”):

  • East-Africa (Olduvai, Omo)
  • 5 million years ago
  • Brain volume: 500 cm3
  • Mainly walked on 2 feet, 110-140 cm tall
  • Used tools but could not make tools
  • Extinction: 1 million years ago

Homo habilis („ügyes ember”)

  • 2-3 million years ago
  • Walked on 2 feet only
  • Brain volume: 7-800 cm3
  • Self-made stone tools
  • Working in groups

Homo erectus („felegyenesedett ember”)

  • 1-1.2 million years ago
  • Brain: 1000-1300 cm3
  • Erected body
  • Fine tools
  • Could use fire

Homo neanderthalensis („Neander-völgyi ember”)

  • Brain: 1400-1450 cm3
  • Strong bones and muscles
  • Were well adapted to the cold glacial climate
  • Lived in caves, fire, tools
  • Primitive speech
  • Hunting, developed social behavior
  • Extinction: 30 000 years ago

Homo sapiens („Bölcs ember”, Cro-magnoni ember)

  • 200 000 years ago
  • Brain: 1350 cm3
  • Spreading out: Africa – Europe – Asia – Australia – North-America – South-America
  • 4 main race: europid, mongoloid, negroid, aboriginal (?)- veddo-australid