1 The origin of birds has long been
1
The origin of birds has long been debated. 2
• The fossil of the earliest known bird, Archeaopteryx, was discovered in 1861 3
Fossils of feathered dinosaurs have been discovered. fossil of Caudipteryx (尾羽龍) 4
They provide evidence to support that birds evolved from reconstructed dinosaurs. Caudipteryx 5
1 How did life originate on earth 6
2 Why are there so many different kinds of organisms on earth today 7
3 What are fossils What is their importance in the study of evolution 8
30. 1 The origins of life How did life originate? 9
Theories on the origin of life on Earth 1. Special creation 10
Theories on the origin of life on Earth 2. Spontaneous generation Maggots from meat 11
Experiments that disapprove spontaneous generation of life Francesco Redi (1626 -1697) • One of the men to dispute "Spontaneous Generation" Did experiment with meat and flies, if flies were prevented from landing on meat, it did not 12 produce maggots
Theories on the origin of life on Earth 4. Cosmic theory 13
Theories on the origin of life on Earth 3. Primodial soup – chemical evolution 14
30. 1 The origins of life Maybe simple organic molecules were formed from inorganic substances present in early earth’s atmosphere by the action of UV radiation and lightning. 15
30. 1 The origins of life The organic molecules then joined to form the first organism. Chemical evolution!! 16
30. 1 The origins of life Let me do an experiment to test this hypothesis. Stanley Miller 17
30. 1 The origins of life electric spark gas mixture of H 2, H 2 O, NH 3, CH 4 boiling water heat 18
30. 1 The origins of life simulated lightning condenser boiling water heat gas mixture of H 2, H 2 O, NH 3, CH 4 water out water in liquid containing organic molecules 19
30. 1 The origins of life This supports the idea that organic molecules can be made from inorganic substances under the conditions of early earth. Stanley Miller 20
30. 1 The origins of life No one knows the exact origins of life. Scientists believe that the first organisms are formed by joining organic molecules together. The organic molecules are produced from simple inorganic substances present in early earth’s atmosphere. 21
30. 2 Biological Evolution What is the origin of the diversified life forms on earth today? 22
Life evolves and our Earth has been changing 23
30. 2 Evolution is defined as the development of complex • organisms from pre-existing simple organisms over the course of time. 24
30. 2 Evolution • scientists generally accept theory of evolution (進化論) - life on earth started from a common ancestor (共同祖先) - this ancestor developed into all the different species today over a long period of time 25
Biological evolution focuses mainly on the relationship between species and major phyla rather than the origin of life 26
Common ancestor of all living things 27
30. 2 Evolution Evidence for evolution: fossils • preserved remains or traces of organisms 28
30. 2 Evolution Evidence for evolution: fossils • most are formed from the hard parts of organisms bones 29
30. 2 Evolution Evidence for evolution: fossils • most are formed from the hard parts of organisms bones shells 30
30. 2 Evolution Evidence for evolution: fossils • most are formed from the hard parts of organisms bones shells teeth wood of trees 31
30. 2 Evolution Evidence for evolution: fossils • eggs, footprints, dung and pollen can also become fossils dinosaur egg fossil 32
30 Million-Year. Old Praying Mantis Is Preserved in Pristine Piece of Amber 33
30. 2 Evolution Evidence for evolution: fossils • eggs, footprints, dung and pollen can also become fossils dinosaur footprint found in Bolivia 34
30. 2 Evolution Evidence for evolution: fossils • eggs, footprints, dung and pollen can also become fossils dung fossil 35
Formation of fossils 36
30. 2 Evolution Formation of fossils mud and sand fish skeleton bottom of a lake 37
30. 2 Evolution Formation of fossils upper layer mud and sand of sediment great pressure fish skeleton bottom of a lake mud and sand become rock 38
30. 2 Evolution Formation of fossils deposition of mineral salts mud and sand become rock 39
30. 2 Evolution Formation of fossils skeleton becomes fossil mud and sand become rock 40
30. 2 Evolution Formation of fossils skeleton becomes fossil mud and sand become rock 41
30. 2 Evolution Formation of fossils rocks rise above water younger rock layer older rock layer earth movement 42
30. 2 Evolution Formation of fossils younger rock layer older rock layer further earth movement or weathering 43
30. 2 Evolution Formation of fossils Video fossil exposed further earth movement or weathering 44
30. 2 Evolution Fossil record • fossils are usually preserved in sedimentary rocks (沉積 岩) 45
30. 2 Evolution Fossil record • fossils are usually preserved in sedimentary rocks (沉積岩) uppermost layer lowest layer 46
30. 2 Evolution Fossil record • fossils are usually preserved in sedimentary rocks (沉積岩) youngest rock most recent fossil oldest rock earliest fossil 47
The grand Canyon shows sections of sediment that have been laid down millions of years ago 48
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30. 2 Evolution Fossil record • a sequence of fossils • from it, the evolutionary history can be traced • shows a developmental change from simple prokaryotic organisms to complex eukaryotic organisms agree with modern classification system 50
30. 2 Evolution Fungi Animalia Plantae eukaryotes Protista prokaryotes Archaebacteria Eubacteria common ancestor 51
30. 2 Evolution Fossil record • estimate age of fossils by radioisotope dating (放射性同位素定年法) time of existence of organisms 52
30. 2 Evolution Fossil record • first appearance of different groups of organisms: land plants 490 humans reptiles mammals birds 420 440 350 200 2 time (million fish amphibians of years dinosaurs ago) 53
30. 2 Evolution of horse 60 million years ago today forelimb 0. 4 m 1 m 1. 6 m body size 54
30. 2 Evolution of horse • from the comparison of their structures: horses became larger in size forelimb 0. 4 m 1 m 1. 6 m body size 55
30. 2 Evolution of horse • from the comparison of their structures: legs became longer forelimb 0. 4 m 1 m 1. 6 m body size 56
30. 2 Evolution of horse • from the comparison of their structures: number of toes reduced forelimb 0. 4 m 1 m 1. 6 m body size 57
Reconstruction of the evolution of horse from fossil record horses became larger legs became longer number of toes reduced 58
30. 2 Evolution Limitations of fossil record • a continuous fossil record is seldom found gaps or missing links (缺少的環節) 59
30. 2 Evolution Limitations of fossil record i) Unable to form fossils • dead bodies may be eaten by other organisms or may decay before fossilization occurs • conditions may not be suitable for fossilization 60
30. 2 Evolution Limitations of fossil record i) Unable to form fossils • some organisms may not be fossilized e. g. soft-bodied organisms 61
30. 2 Evolution Limitations of fossil record ii) Unable to find a complete set of fossils • some fossils are located in inaccessible areas • most fossils are incomplete and may be damaged • chance of discovery is low 62
Evidence for evolution: comparative anatomy 63
Evidence for evolution: comparative anatomy – vestigial structure 64
Pelvis and hind limb bones in whale cormorant Erector muscle in human skin Flightless cormorant 65
Evidence for evolution: artificial selection 66
• Artificial selection has produced dramatic change in domesticated species 67
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Wild relatives of domesticated plants 69
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Wild relatives of domesticated plants 71
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Evidence for evolution: comparing key proteins 73
30. 2 Evolution Evidence for evolution: genetic similarities • body characteristics are determined by the base sequence of DNA G A C G T A A G C G 74
30. 2 Evolution Evidence for evolution: genetic similarities • organisms with closer evolutionary relationship would have accumulated less genetic differences 75
https: //www. youtube. com/watch ? v=l. QHo 7 nlqjsg 76
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30. 2 Evolution Evidence for evolution: genetic similarities • the more similar the base sequence, the closer the evolutionary relationship 98% 85% similarity in base sequence 78
Homology of molecules 79
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30. 2 Evolution Evidence for evolution: genetic similarities • the more similar the base sequence, the closer the evolutionary relationship more closely related 81
https: //www. youtube. com/watch ? v=P 3 Gagfb. A 2 vo 82
1 How did life originate on earth? The origins of life is still unknown today. It is generally believed that organic molecules were first formed from simple inorganic substances present in early earth’s atmosphere. 83
1 How did life originate on earth? The organic molecules then joined to form the first organisms. 84
2 Why are there so many different kinds of organisms on earth today? Most biologists believe that the different kinds of organisms on earth today evolved from a common ancestor over a long period of time. 85
3 What are fossils? What is their importance in the study of evolution? Fossils are the preserved remains or traces of organisms. They provide evidence for evolution. 86
Evolution can explain diversified life forms come from a common ancestor 87
Evolution supported by evidence like genetic similarities fossil record 88
fossil record found in sedimentary rock lower layers contain simpler life forms upper layers contain more complex life forms 89
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