History of Life on Earth

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History of Life on Earth

• Chapter 25

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Macroevolution

• Evolutionary change above a species
• Evolution on a grand scale
• Species in a new habitat
• Mass extinctions

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Early Earth

• 4.6 billion years ago (bya)
• 3.5 bya microorganism (prokaryote)
• 1. Abiotic formation of small organic molecules
  (aa)
• 2. Macromolecules
• 3. Packaging into membranes
• 4. Replication

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Early Earth

• Protobionts
• Collections of abiotic materials
• Surrounded by membrane-like structures
• Ribozymes
• RNA catalysts

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Fossils
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Fossils
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Fig. 25-4
Rhomaleosaurus victor, a plesiosaur
Present
Dimetrodon
100 million years ago
Casts of ammonites
175
200
270
300
Hallucigenia
4.5 cm
375
Coccosteus cuspidatus
400
1 cm
Dickinsonia costata
500
525
2.5 cm
565
Stromatolites
Tappania, a unicellular eukaryote
600
3,500 1,500
Fossilized stromatolite
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Geologic record

• Fossils outline earths history

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Fossils

• Mammals
• Jaw bone
• Ear bones
• Teeth

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Fig. 25-6
Synapsid (300 mya)
Temporal fenestra
Key
Articular
Dentary
Quadrate
Squamosal
Therapsid (280 mya)
Reptiles (including dinosaurs and birds)
Temporal fenestra
EARLY TETRAPODS
Dimetrodon
Early cynodont (260 mya)
Synapsids
Very late cynodonts
Temporal fenestra
Earlier cynodonts
Therapsids
Later cynodont (220 mya)
Mammals
Very late cynodont (195 mya)
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Fig. 25-7
Ceno- zoic
Meso- zoic
Humans
Paleozoic
Colonization of land
Animals
Origin of solar system and Earth
1
4
Proterozoic
Archaean
Prokaryotes
years ago
Billions of
3
2
Multicellular eukaryotes
Single-celled eukaryotes
Atmospheric oxygen
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Fig 25-UN2
1
4
Billions of
years ago
3
2
Prokaryotes
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Prokaryotes

• Stromatolites
• Layers of rock
• Form when prokaryotes bind thin layers of
  sediment together
• 3.5 billion years ago
• Present day
• Warm environments

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Fig 25-UN3
1
4
Billions of
years ago
2
3
Atmospheric oxygen
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Oxygen

• Photosynthetic bacteria
• Cynobacteria
• Iron oxide formed in sediments
• 2.5 billion years ago

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Fig. 25-8
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Fig 25-UN4
1
4
Billions of
years ago
3
2
Single- celled eukaryotes
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Eukaryotes

• 2.1 billion years ago
• Endosymbiosis
• Mitochondria plastids (chloroplasts)

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Fig. 25-9-4
Cytoplasm
Plasma membrane
DNA
Ancestral prokaryote
Endoplasmic reticulum
Nucleus
Nuclear envelope
Aerobic heterotrophic prokaryote
Photosynthetic prokaryote
Mitochondrion
Mitochondrion
Ancestral heterotrophic eukaryote
Plastid
Ancestral photosynthetic eukaryote
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Fig 25-UN5
1
4
Billions of
years ago
2
3
Multicellular eukaryotes
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Multicellular eukaryotes

• 1.5 billion years ago
• snowball earth
• Limited diversity

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Fig 25-UN6
Animals
1
4
Billions of
years ago
3
2
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Cambrian explosion

• 535-525 mya
• Increase in diversity of animals
• Phyla

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Fig. 25-10
500
Sponges
Cnidarians
Annelids
Molluscs
Chordates
Arthropods
Brachiopods
Echinoderms
Early Paleozoic era (Cambrian period)
Millions of years ago
542
Late Proterozoic eon
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Fig 25-UN7
Colonization of land
1
4
Billions of
years ago
3
2
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Colonization to land

• 500 mya
• Plants, fungi
• Tetrapods 365 mya
• Hominoids (apes) 6-7 mya
• Humans 195,000 years ago

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Fig 25-UN8
1.2 bya First multicellular eukaryotes
535525 mya Cambrian explosion (great
increase in diversity of animal forms)
500 mya Colonization of land by fungi,
plants and animals
2.1 bya First eukaryotes (single-celled)
3.5 billion years ago (bya) First prokaryotes
(single-celled)
500
1,000
1,500
2,000
3,000
2,500
3,500
4,000
Present
Millions of years ago (mya)
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Change in dominant groups

• 1. land movement
• 2. mass extinctions
• 3. adaptive radiation

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Land movement

• Continental drift
• Movement of earths continental plates
• 3 times all landmasses came together
• (1.1 bya, 600 mya and 250 mya)
• Pangaea
• all land
• All masses together

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Fig. 25-13b
Laurasia
135
Gondwana
Mesozoic
Millions of years ago
Pangaea
251
Paleozoic
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Fig. 25-13a
Present
Cenozoic
North America
Eurasia
Millions of years ago
Africa
65.5
India
South America
Madagascar
Australia
Antarctica
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Fig. 25-13
Present
Cenozoic
Eurasia
North America
Africa
65.5
India
South America
Australia
Madagascar
Antarctica
Laurasia
135
Mesozoic
Gondwana
Millions of years ago
Pangaea
251
Paleozoic
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Land movement

• Climate changes
• Physical changes (mountains vs oceans)
• Allopatric speciation

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Mass extinctions

• 5 over past 500 mya
• Permian (251 mya)
• Eliminated 75 marine life
• Massive volcano eruptions
• Cretaceous (65.5 mya)
• Dinosaurs
• ?? asteroid

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Fig. 25-14
800
20
700
600
15
500
Number of families
400
Total extinction rate (families per million
years)
10
300
200
5
100
0
0
Mesozoic
Cenozoic
Paleozoic
Era Period
E
C
Tr
C
O
S
D
P
J
P
N
200
145
542
488
444
416
359
299
251
65.5
0
Time (millions of years ago)
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Fig. 25-15
NORTH AMERICA
Chicxulub crater
Yucatán Peninsula
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Mass extinction

• Decrease diversity
• Change ecological communities
• Allows some species to thrive
• Humans evolved

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Adaptive radiation

• Organisms form new species
• Evolve to fill new communities
• Occurred after extinctions
• Now vacant niches
• Mammals
• Hawaii

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Fig. 25-17
Ancestral mammal
Monotremes (5 species)
ANCESTRAL CYNODONT
Marsupials (324 species)
Eutherians (placental mammals 5,010 species)
200
50
250
150
100
0
Millions of years ago
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Fig. 25-18a
1.3 million years
KAUAI 5.1 million years
MOLOKAI
MAUI
OAHU 3.7 million years
LANAI
HAWAII 0.4 million years
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Genes influence evolution

• Heterochrony
• different time
• Change in the rate of development
• Paedomorphosis
• Adult retains juvenile features

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Fig. 25-19
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Newborn
Adult
5
2
Age (years)
(a) Differential growth rates in a human
Chimpanzee fetus
Chimpanzee adult
Human adult
Human fetus
(b) Comparison of chimpanzee and human skull
growth
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Genes influence evolution

• Homeotic genes
• Master genes
• Spatial orientation
• Wing placement
• Leg placement
• Hox gene

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Evolution is not goal driven

• Results from interactions between organism its
  environment
• Human eye
• Complex
• Squid/octopuses