History of Life Part 3

Proterozoic Eon 2.5 bya – 543 mya stable continents first appear Most life are Bacteria and Archaeans first evidence of oxygen build-up in the atmosphere This global catastrophe spelled doom for many bacterial groups & made possible the explosion of eukaryotic forms.

Endosymbiosis The rise of Eukarya 1.8 bya What does it mean? Endo = within sym = together biosis = life Endosymbiosis = organisms of a different species living together, with one of the organisms living within the other Symbiosis between different species of eubacteria & between archeabacteria and eubacteria The rise of Eukarya 1.8 bya 4 4

Prokaryotes lead to Eukaryotes 5 5

Endosymbiosis Increases Organism Complexity

Croanoflagelado: -last unicellular ancestor of all eukaryotes -Characteristics similar to modern protista 8

800 mya: 1st-multicellular organism Sphaeroeca, a colony of choanoflagellates ~230 individuals cooperatively linked protists 10

850 MYA First Fungi Amber fossils the fossil on right are fungal filaments resemble living filaments of common Candida species. the fossil at right has preserved the perithecium with spores used for reproduction.

760 MYA-First Animal Otavia antiqua -a sea spongue

14 14

Typical day in a late PreCambrian sea… 15 15

Trilobites: the 1st exoskeletons. 16

Cambrian Explosion: ~570mya- 500mya Finally the ocean is full of animals with hard parts… by the early Paleozoic there are lots of animals that can form fossils. Cambrian Explosion: ~570mya- 500mya 17 17

Cambrian Explosion: A sudden explosion of complex, multicellular life at the beginning of the Paleozoic Many of these early animals looked very strange, unlike any animals we find on Earth today. 18

Opibinia… 1st macroscopic predator 19 19

Most of the major phyla originated over several million years during the early Paleozoic… 20 20

520 mya Pikaia: 1st Chordate 21

22 22

Typical day in late PreCambrian sea… 23 23

Jawless Fish Earliest Fish 500 mya 24

Armored Fish 25

Lobed Finned Fish 26

27

Plants Move Onto Land 28

480 MYA- First Land Plant The cryptospores are the oldest land plant fossils found. Petrified fossils

Animals Move Onto Land 30 30

31

32 32

Fish to Amphibian

370 mya: Amphibians Tiktaalik: fish-amphibian transition fossil 34

35 35

~310 mya 1st REPTILES first animals with backbones able to live on dry land Ex Thecodont

Earliest Dinosaur Eoraptor 230 mya Argentina 3 ft long 10 lbs Carnivor “dawn theif” 230 mya Argentina 3 ft long 10 lbs Carnivor Bipedial 37

How is a dinosaur different from a reptile? 38

Flying Reptiles Appeared ~ 230mya, around the same time as dinosaurs. They were the first vertebrates to fly. 39

40

41

Georgia Eoraptor site 42

Reptiles to Mammals

Earliest Mammal Megazostrodon found in Africa ~ 220 mya mega-large, zostros-girdle odon-tooth found in Africa ~ 220 mya 4-5 inches long Carnivore Laid eggs 44

Reptiles to Birds 45

most small theropod dinosaurs were covered in feathers. 46

47

48

Earliest Bird Archaeopteryx “Ancient wing” ~150 mya 49

50

The late Cretaceous was a time of intense volcanic activity. For many millions of years the atmosphere was modified by the release of volcanic gases and ash. 51

Major Extinction Event 65 mya 65% all species become extinct, including all non-avian dinosaurs Worse for large animals Marked the end of the Mesozoic 52

53

Impact at Chixulub in Yuccatan Peninsula 54

Post Ice Age: Large Mammals Ground Sloth: 20 mya

first to travel long distances & use fire 2.5 MYA- Homo habilis 175,000 yr ago- Homo sapiens 1.8 MYA- Home erectus first to travel long distances & use fire 2.5 MYA- Homo habilis First tool user 3.9 MYA- Australopithecus afarensis First bipedalism